Java Edition protocol

This article presents a dissection of the current Java Edition protocol for 1.21.4, protocol 769.

The changes between versions may be viewed at Protocol History.

Definitions

The Minecraft server accepts connections from TCP clients and communicates with them using packets. A packet is a sequence of bytes sent over the TCP connection. The meaning of a packet depends both on its packet ID and the current state of the connection. The initial state of each connection is Handshaking, and state is switched using the packets Handshake and Login Success.

Data types

All data sent over the network (except for VarInt and VarLong) is big-endian, that is the bytes are sent from most significant byte to least significant byte. The majority of everyday computers are little-endian, therefore it may be necessary to change the endianness before sending data over the network.

Name	Size (bytes)	Encodes	Notes
Boolean	1	Either false or true	True is encoded as 0x01, false as 0x00.
Byte	1	An integer between -128 and 127	Signed 8-bit integer, two's complement
Unsigned Byte	1	An integer between 0 and 255	Unsigned 8-bit integer
Short	2	An integer between -32768 and 32767	Signed 16-bit integer, two's complement
Unsigned Short	2	An integer between 0 and 65535	Unsigned 16-bit integer
Int	4	An integer between -2147483648 and 2147483647	Signed 32-bit integer, two's complement
Long	8	An integer between -9223372036854775808 and 9223372036854775807	Signed 64-bit integer, two's complement
Float	4	A single-precision 32-bit IEEE 754 floating point number
Double	8	A double-precision 64-bit IEEE 754 floating point number
String (n)	≥ 1 ≤ (n×3) + 3	A sequence of Unicode scalar values	UTF-8 string prefixed with its size in bytes as a VarInt. Maximum length of n characters, which varies by context. The encoding used on the wire is regular UTF-8, not Java's "slight modification". However, the length of the string for purposes of the length limit is its number of UTF-16 code units, that is, scalar values > U+FFFF are counted as two. Up to n × 3 bytes can be used to encode a UTF-8 string comprising n code units when converted to UTF-16, and both of those limits are checked. Maximum n value is 32767. The + 3 is due to the max size of a valid length VarInt.
Text Component	Varies	See Text formatting#Text components	Encoded as a NBT Tag, with the type of tag used depending on the case: As a String Tag: For components only containing text (no styling, no events etc.). As a Compound Tag: Every other case.
JSON Text Component	≥ 1 ≤ (262144×3) + 3	See Text formatting#Text components	The maximum permitted length when decoding is 262144, but the vanilla server since 1.20.3 refuses to encode longer than 32767. This may be a bug.
Identifier	≥ 1 ≤ (32767×3) + 3	See Identifier below	Encoded as a String with max length of 32767.
VarInt	≥ 1 ≤ 5	An integer between -2147483648 and 2147483647	Variable-length data encoding a two's complement signed 32-bit integer; more info in their section
VarLong	≥ 1 ≤ 10	An integer between -9223372036854775808 and 9223372036854775807	Variable-length data encoding a two's complement signed 64-bit integer; more info in their section
Entity Metadata	Varies	Miscellaneous information about an entity	See Minecraft Wiki:Projects/wiki.vg merge/Entity metadata#Entity Metadata Format
Slot	Varies	An item stack in an inventory or container	See Slot Data
NBT	Varies	Depends on context	See NBT
Position	8	An integer/block position: x (-33554432 to 33554431), z (-33554432 to 33554431), y (-2048 to 2047)	x as a 26-bit integer, followed by z as a 26-bit integer, followed by y as a 12-bit integer (all signed, two's complement). See also the section below.
Angle	1	A rotation angle in steps of 1/256 of a full turn	Whether or not this is signed does not matter, since the resulting angles are the same.
UUID	16	A UUID	Encoded as an unsigned 128-bit integer (or two unsigned 64-bit integers: the most significant 64 bits and then the least significant 64 bits)
BitSet	Varies	See #BitSet below	A length-prefixed bit set.
Fixed BitSet (n)	ceil(n / 8)	See #Fixed BitSet below	A bit set with a fixed length of n bits.
Optional X	0 or size of X	A field of type X, or nothing	Whether or not the field is present must be known from the context.
Prefixed Optional X	size of Boolean + (is present ? Size of X : 0)	A boolean and if present, a field of type X	The boolean is true if the field is present.
Array of X	length times size of X	Zero or more fields of type X	The length must be known from the context.
Prefixed Array of X	size of VarInt + size of X * length	See #Prefixed Array below	A length-prefixed array.
X Enum	size of X	A specific value from a given list	The list of possible values and how each is encoded as an X must be known from the context. An invalid value sent by either side will usually result in the client being disconnected with an error or even crashing.
Byte Array	Varies	Depends on context	This is just a sequence of zero or more bytes, its meaning should be explained somewhere else, e.g. in the packet description. The length must also be known from the context.
ID or X	size of VarInt + (size of X or 0)	See #ID or X below	Either a registry ID or an inline data definition of type X.
ID Set	Varies	See #ID Set below	Set of registry IDs specified either inline or as a reference to a tag.
Sound Event	Varies	See #Sound Event below	Parameters for a sound event.
Teleport Flags	4	See #Teleport Flags below	Bit field specifying how a teleportation is to be applied on each axis.
Recipe Display	Varies	See Recipes#Recipe Display structure	Description of a recipe for use for use by the client.
Slot Display	Varies	See Recipes#Slot Display structure	Description of a recipe ingredient slot for use for use by the client.
Chunk Data	Varies	See #Chunk Data below
Light Data	Varies	See #Light Data below

Identifier

Identifiers are a namespaced location, in the form of minecraft:thing. If the namespace is not provided, it defaults to minecraft (i.e. thing is minecraft:thing). Custom content should always be in its own namespace, not the default one. Both the namespace and value can use all lowercase alphanumeric characters (a-z and 0-9), dot (.), dash (-), and underscore (_). In addition, values can use slash (/). The naming convention is lower_case_with_underscores. More information. For ease of determining whether a namespace or value is valid, here are regular expressions for each:

• Namespace: [a-z0-9.-_]
• Value: [a-z0-9.-_/]

VarInt and VarLong

Variable-length format such that smaller numbers use fewer bytes. These are very similar to Protocol Buffer Varints: the 7 least significant bits are used to encode the value and the most significant bit indicates whether there's another byte after it for the next part of the number. The least significant group is written first, followed by each of the more significant groups; thus, VarInts are effectively little endian (however, groups are 7 bits, not 8).

VarInts are never longer than 5 bytes, and VarLongs are never longer than 10 bytes. Within these limits, unnecessarily long encodings (e.g. 81 00 to encode 1) are allowed.

Pseudocode to read and write VarInts and VarLongs:

private static final int SEGMENT_BITS = 0x7F;
private static final int CONTINUE_BIT = 0x80;

public int readVarInt() {
    int value = 0;
    int position = 0;
    byte currentByte;

    while (true) {
        currentByte = readByte();
        value |= (currentByte & SEGMENT_BITS) << position;

        if ((currentByte & CONTINUE_BIT) == 0) break;

        position += 7;

        if (position >= 32) throw new RuntimeException("VarInt is too big");
    }

    return value;
}

public long readVarLong() {
    long value = 0;
    int position = 0;
    byte currentByte;

    while (true) {
        currentByte = readByte();
        value |= (long) (currentByte & SEGMENT_BITS) << position;

        if ((currentByte & CONTINUE_BIT) == 0) break;

        position += 7;

        if (position >= 64) throw new RuntimeException("VarLong is too big");
    }

    return value;
}

public void writeVarInt(int value) {
    while (true) {
        if ((value & ~SEGMENT_BITS) == 0) {
            writeByte(value);
            return;
        }

        writeByte((value & SEGMENT_BITS) | CONTINUE_BIT);

        // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
        value >>>= 7;
    }
}

public void writeVarLong(long value) {
    while (true) {
        if ((value & ~((long) SEGMENT_BITS)) == 0) {
            writeByte(value);
            return;
        }

        writeByte((value & SEGMENT_BITS) | CONTINUE_BIT);

        // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
        value >>>= 7;
    }
}

Sample VarInts:

Value	Hex bytes	Decimal bytes
0	0x00	0
1	0x01	1
2	0x02	2
127	0x7f	127
128	0x80 0x01	128 1
255	0xff 0x01	255 1
25565	0xdd 0xc7 0x01	221 199 1
2097151	0xff 0xff 0x7f	255 255 127
2147483647	0xff 0xff 0xff 0xff 0x07	255 255 255 255 7
-1	0xff 0xff 0xff 0xff 0x0f	255 255 255 255 15
-2147483648	0x80 0x80 0x80 0x80 0x08	128 128 128 128 8

Sample VarLongs:

Value	Hex bytes	Decimal bytes
0	0x00	0
1	0x01	1
2	0x02	2
127	0x7f	127
128	0x80 0x01	128 1
255	0xff 0x01	255 1
2147483647	0xff 0xff 0xff 0xff 0x07	255 255 255 255 7
9223372036854775807	0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0x7f	255 255 255 255 255 255 255 255 127
-1	0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0x01	255 255 255 255 255 255 255 255 255 1
-2147483648	0x80 0x80 0x80 0x80 0xf8 0xff 0xff 0xff 0xff 0x01	128 128 128 128 248 255 255 255 255 1
-9223372036854775808	0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x80 0x01	128 128 128 128 128 128 128 128 128 1

Position

Note: What you are seeing here is the latest version of the Data types article, but the position type was different before 1.14.

64-bit value split into three signed integer parts:

• x: 26 MSBs
• z: 26 middle bits
• y: 12 LSBs

For example, a 64-bit position can be broken down as follows:

Example value (big endian): 01000110000001110110001100 10110000010101101101001000 001100111111

• The red value is the X coordinate, which is 18357644 in this example.
  
• The blue value is the Z coordinate, which is -20882616 in this example.
  
• The green value is the Y coordinate, which is 831 in this example.
  

Encoded as follows:

((x & 0x3FFFFFF) << 38) | ((z & 0x3FFFFFF) << 12) | (y & 0xFFF)

And decoded as:

val = read_long();
x = val >> 38;
y = val << 52 >> 52;
z = val << 26 >> 38;

Note: The above assumes that the right shift operator sign extends the value (this is called an arithmetic shift), so that the signedness of the coordinates is preserved. In many languages, this requires the integer type of val to be signed. In the absence of such an operator, the following may be useful:

if x >= 1 << 25 { x -= 1 << 26 }
if y >= 1 << 11 { y -= 1 << 12 }
if z >= 1 << 25 { z -= 1 << 26 }

Fixed-point numbers

Some fields may be stored as fixed-point numbers, where a certain number of bits represent the signed integer part (number to the left of the decimal point) and the rest represent the fractional part (to the right). Floating point numbers (float and double), in contrast, keep the number itself (mantissa) in one chunk, while the location of the decimal point (exponent) is stored beside it. Essentially, while fixed-point numbers have lower range than floating point numbers, their fractional precision is greater for higher values.

Prior to version 1.9 a fixed-point format with 5 fraction bits and 27 integer bits was used to send entity positions to the client. Some uses of fixed point remain in modern versions, but they differ from that format.

Most programming languages lack support for fractional integers directly, but you can represent them as integers. The following C or Java-like pseudocode converts a double to a fixed-point integer with n fraction bits:

 x_fixed = (int)(x_double * (1 << n));

And back again:

 x_double = (double)x_fixed / (1 << n);

Arrays

The types Array and Prefixed Array represent a collection of X in a specified order.

Array

Represents a list where the length is not encoded. The length must be known from the context. If the array is empty nothing will be encoded.

A String Array with the values ["Hello", "World!"] has the following data when encoded:

Field Name	Field Type	Value
First element	String	Hello
Second element	String	World!

Prefixed Array

Represents an array prefixed by its length. If the array is empty the length will still be encoded.

Field Name	Field Type
Length	VarInt
Data	Array of X

Bit sets

The types BitSet and Fixed BitSet represent packed lists of bits. The vanilla implementation uses Java's BitSet class.

BitSet

Bit sets of type BitSet are prefixed by their length in longs.

Field Name	Field Type	Meaning
Length	VarInt	Number of longs in the following array. May be 0 (if no bits are set).
Data	Array of Long	A packed representation of the bit set as created by BitSet.toLongArray.

The ith bit is set when (Data[i / 64] & (1 << (i % 64))) != 0, where i starts at 0.

Fixed BitSet

Bit sets of type Fixed BitSet (n) have a fixed length of n bits, encoded as ceil(n / 8) bytes. Note that this is different from BitSet, which uses longs.

Field Name	Field Type	Meaning
Data	Byte Array (n)	A packed representation of the bit set as created by BitSet.toByteArray, padded with zeroes at the end to fit the specified length.

The ith bit is set when (Data[i / 8] & (1 << (i % 8))) != 0, where i starts at 0. This encoding is not equivalent to the long array in BitSet.

Registry references

ID or X

Represents a data record of type X, either inline, or by reference to a registry implied by context.

Field Name	Field Type	Meaning
ID	VarInt	0 if value of type X is given inline; otherwise registry ID + 1.
Value	Optional X	Only present if ID is 0.

ID Set

Represents a set of IDs in a certain registry (implied by context), either directly (enumerated IDs) or indirectly (tag name).

Field Name	Field Type	Meaning
Type	VarInt	Value used to determine the data that follows. It can be either: 0 - Represents a named set of IDs defined by a tag. Anything else - Represents an ad-hoc set of IDs enumerated inline.
Tag Name	Optional Identifier	The registry tag defining the ID set. Only present if Type is 0.
IDs	Optional Array of VarInt	An array of registry IDs. Only present if Type is not 0. The size of the array is equal to Type - 1.

Registry data

These types are commonly used in conjuction with ID or X to specify custom data inline.

Sound Event

Describes a sound that can be played.

Name	Type	Description
Sound Name	Identifier
Has Fixed Range	Boolean	Whether this sound has a fixed range, as opposed to a variable volume based on distance.
Fixed Range	Optional Float	The maximum range of the sound. Only present if Has Fixed Range is true.

Teleport Flags

A bit field represented as an Int, specifying how a teleportation is to be applied on each axis.

In the lower 8 bits of the bit field, a set bit means the teleportation on the corresponding axis is relative, and an unset bit that it is absolute.

Hex Mask	Field
0x0001	Relative X
0x0002	Relative Y
0x0004	Relative Z
0x0008	Relative Yaw
0x0010	Relative Pitch
0x0020	Relative Velocity X
0x0040	Relative Velocity Y
0x0080	Relative Velocity Z
0x0100	Rotate velocity according to the change in rotation, before applying the velocity change in this packet. Combining this with absolute rotation works as expected—the difference in rotation is still used.

Chunk Data

Field Name		Field Type		Notes
Heightmaps		NBT		See Chunk Format#Heightmaps structure
Data		Prefixed Array of Byte		See Chunk Format#Data structure
Block Entities	Packed XZ	Prefixed Array	Unsigned Byte	The packed section coordinates are relative to the chunk they are in. Values 0-15 are valid. packed_xz = ((blockX & 15) << 4) | (blockZ & 15) // encode x = packed_xz >> 4, z = packed_xz & 15 // decode
	Y		Short	The height relative to the world
	Type		VarInt	The type of block entity
	Data		NBT	The block entity's data, without the X, Y, and Z values

Light Data

Field Name		Field Type		Notes
Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Sky Light array below. The least significant bit is for blocks 16 blocks to 1 block below the min world height (one section below the world), while the most significant bit covers blocks 1 to 16 blocks above the max world height (one section above the world).
Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Block Light array below. The order of bits is the same as in Sky Light Mask.
Empty Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Sky Light data. The order of bits is the same as in Sky Light Mask.
Empty Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Block Light data. The order of bits is the same as in Sky Light Mask.
Sky Light arrays	Sky Light array	Prefixed Array	Prefixed Array (2048) of Byte	The length of any inner array is always 2048; There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
Block Light arrays	Block Light array	Prefixed Array	Prefixed Array (2048) of Byte	The length of any inner array is always 2048; There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.

Other definitions

Term	Definition
Player	When used in the singular, Player always refers to the client connected to the server.
Entity	Entity refers to any item, player, mob, minecart or boat etc. See the Minecraft Wiki article for a full list.
EID	An EID — or Entity ID — is a 4-byte sequence used to identify a specific entity. An entity's EID is unique on the entire server.
XYZ	In this document, the axis names are the same as those shown in the debug screen (F3). Y points upwards, X points east, and Z points south.
Meter	The meter is Minecraft's base unit of length, equal to the length of a vertex of a solid block. The term “block” may be used to mean “meter” or “cubic meter”.
Registry	A table describing static, gameplay-related objects of some kind, such as the types of entities, block states or biomes. The entries of a registry are typically associated with textual or numeric identifiers, or both. Minecraft has a unified registry system used to implement most of the registries, including blocks, items, entities, biomes and dimensions. These "ordinary" registries associate entries with both namespaced textual identifiers (see #Identifier), and signed (positive) 32-bit numeric identifiers. There is also a registry of registries listing all of the registries in the registry system. Some other registries, most notably the block state registry, are however implemented in a more ad-hoc fashion. Some registries, such as biomes and dimensions, can be customized at runtime by the server (see Registry Data), while others, such as blocks, items and entities, are hardcoded. The contents of the hardcoded registries can be extracted via the built-in Data Generators system.
Block state	Each block in Minecraft has 0 or more properties, which in turn may have any number of possible values. These represent, for example, the orientations of blocks, poweredness states of redstone components, and so on. Each of the possible permutations of property values for a block is a distinct block state. The block state registry assigns a numeric identifier to every block state of every block. A current list of properties and state ID ranges is found on burger. Alternatively, the vanilla server now includes an option to export the current block state ID mapping, by running java -DbundlerMainClass=net.minecraft.data.Main -jar minecraft_server.jar --reports. See Data Generators for more information.
Vanilla	The official implementation of Minecraft as developed and released by Mojang.
Sequence	The action number counter for local block changes, incremented by one when clicking a block with a hand, right clicking an item, or starting or finishing digging a block. Counter handles latency to avoid applying outdated block changes to the local world. Also is used to revert ghost blocks created when placing blocks, using buckets, or breaking blocks.

Packet format

Packets cannot be larger than 2²¹ − 1 or 2097151 bytes (the maximum that can be sent in a 3-byte VarInt). Moreover, the length field must not be longer than 3 bytes, even if the encoded value is within the limit. Unnecessarily long encodings at 3 bytes or below are still allowed. For compressed packets, this applies to the Packet Length field, i.e. the compressed length.

Without compression

Field Name	Field Type	Notes
Length	VarInt	Length of Packet ID + Data
Packet ID	VarInt	Corresponds to protocol_id from the server's packet report
Data	Byte Array	Depends on the connection state and packet ID, see the sections below

With compression

Once a Set Compression packet (with a non-negative threshold) is sent, zlib compression is enabled for all following packets. The format of a packet changes slightly to include the size of the uncompressed packet.

Present?	Compressed?	Field Name	Field Type	Notes
always	No	Packet Length	VarInt	Length of (Data Length) + length of compressed (Packet ID + Data)
if size >= threshold	No	Data Length	VarInt	Length of uncompressed (Packet ID + Data)
	Yes	Packet ID	VarInt	zlib compressed packet ID (see the sections below)
		Data	Byte Array	zlib compressed packet data (see the sections below)
if size < threshold	No	Data Length	VarInt	0 to indicate uncompressed
		Packet ID	VarInt	packet ID (see the sections below)
		Data	Byte Array	packet data (see the sections below)

For serverbound packets, the uncompressed length of (Packet ID + Data) must not be greater than 2²³ or 8388608 bytes. Note that a length equal to 2²³ is permitted, which differs from the compressed length limit. The vanilla client, on the other hand, has no limit for the uncompressed length of incoming compressed packets.

If the size of the buffer containing the packet data and ID (as a VarInt) is smaller than the threshold specified in the packet Set Compression. It will be sent as uncompressed. This is done by setting the data length as 0. (Comparable to sending a non-compressed format with an extra 0 between the length, and packet data).

If it's larger than or equal to the threshold, then it follows the regular compressed protocol format.

The vanilla server (but not client) rejects compressed packets smaller than the threshold. Uncompressed packets exceeding the threshold, however, are accepted.

Compression can be disabled by sending the packet Set Compression with a negative Threshold, or not sending the Set Compression packet at all.

Handshaking

Clientbound

There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.

Serverbound

Handshake

This packet causes the server to switch into the target state. It should be sent right after opening the TCP connection to prevent the server from disconnecting.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: intention	Handshaking	Server	Protocol Version	VarInt	See protocol version numbers (currently 769 in Minecraft 1.21.4).
			Server Address	String (255)	Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The vanilla server does not use this information. Note that SRV records are a simple redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide example.org as server address in addition to connecting to it.
			Server Port	Unsigned Short	Default is 25565. The vanilla server does not use this information.
			Next State	VarInt Enum	1 for Status, 2 for Login, 3 for Transfer.

Legacy Server List Ping

While not technically part of the current protocol, (legacy) clients may send this packet to initiate Server List Ping, and modern servers should handle it correctly. The format of this packet is a remnant of the pre-Netty age, before the switch to Netty in 1.7 brought the standard format that is recognized now. This packet merely exists to inform legacy clients that they can't join our modern server.

Modern clients (tested with 1.21.5 + 1.21.4) also send this packet when the server does not send any response within a 30 seconds time window or when the connection is immediately closed.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0xFE	Handshaking	Server	Payload	Unsigned Byte	always 1 (0x01).

See Server List Ping#1.6 for the details of the protocol that follows this packet.

Status

Clientbound

Status Response

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: status_response	Status	Client	JSON Response	String (32767)	See Server List Ping#Status Response; as with all strings this is prefixed by its length as a VarInt.

Pong Response (status)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: pong_response	Status	Client	Timestamp	Long	Should match the one sent by the client.

Serverbound

Status Request

The status can only be requested once immediately after the handshake, before any ping. The server won't respond otherwise.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: status_request	Status	Server	no fields

Ping Request (status)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: ping_request	Status	Server	Timestamp	Long	May be any number, but vanilla clients use will always use the timestamp in milliseconds.

Login

The login process is as follows:

1. C→S: Handshake with Next State set to 2 (login)
2. C→S: Login Start
3. S→C: Encryption Request
4. Client auth (if enabled)
5. C→S: Encryption Response
6. Server auth (if enabled)
7. Both enable encryption
8. S→C: Set Compression (optional)
9. S→C: Login Success
10. C→S: Login Acknowledged

Set Compression, if present, must be sent before Login Success. Note that anything sent after Set Compression must use the Post Compression packet format.

Three modes of operation are possible depending on how the packets are sent:

• Online-mode with encryption
• Offline-mode with encryption
• Offline-mode without encryption

For online-mode servers (the ones with authentication enabled), encryption is always mandatory, and the entire process described above needs to be followed.

For offline-mode servers (the ones with authentication disabled), encryption is optional, and part of the process can be skipped. In that case Login Start is directly followed by Login Success. The vanilla server only uses UUID v3 for offline player UUIDs, deriving it from the string OfflinePlayer:<player's name> For example, Notch’s offline UUID would be chosen from the string OfflinePlayer:Notch. This is not a requirement however, the UUID can be set to anything.

As of 1.21, the vanilla server never uses encryption in offline mode.

See protocol encryption for details.

Clientbound

Disconnect (login)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: login_disconnect	Login	Client	Reason	JSON Text Component	The reason why the player was disconnected.

Encryption Request

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: hello	Login	Client	Server ID	String (20)	Always empty when sent by the vanilla server.
			Public Key	Prefixed Array of Byte	The server's public key, in bytes.
			Verify Token	Prefixed Array of Byte	A sequence of random bytes generated by the server.
			Should authenticate	Boolean	Whether the client should attempt to authenticate through mojang servers.

See protocol encryption for details.

Login Success

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x02 resource: login_finished	Login	Client	UUID		UUID
			Username		String (16)
			Property	Name	Prefixed Array (16)	String (64)
				Value		String (32767)
				Signature		Prefixed Optional String (1024)

The Property field looks like response of Mojang API#UUID to Profile and Skin/Cape, except using the protocol format instead of JSON. That is, each player will usually have one property with Name being “textures” and Value being a base64-encoded JSON string, as documented at Mojang API#UUID to Profile and Skin/Cape. An empty properties array is also acceptable, and will cause clients to display the player with one of the two default skins depending their UUID (again, see the Mojang API page).

Set Compression

Enables compression. If compression is enabled, all following packets are encoded in the compressed packet format. Negative values will disable compression, meaning the packet format should remain in the uncompressed packet format. However, this packet is entirely optional, and if not sent, compression will also not be enabled (the vanilla server does not send the packet when compression is disabled).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: login_compression	Login	Client	Threshold	VarInt	Maximum size of a packet before it is compressed.

Login Plugin Request

Used to implement a custom handshaking flow together with Login Plugin Response.

Unlike plugin messages in "play" mode, these messages follow a lock-step request/response scheme, where the client is expected to respond to a request indicating whether it understood. The vanilla client always responds that it hasn't understood, and sends an empty payload.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x04 resource: custom_query	Login	Client	Message ID	VarInt	Generated by the server - should be unique to the connection.
			Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (1048576)	Any data, depending on the channel. The length of this array must be inferred from the packet length.

Cookie Request (login)

Requests a cookie that was previously stored.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x05 resource: cookie_request	Login	Client	Key		Identifier		The identifier of the cookie.

Serverbound

Login Start

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: hello	Login	Server	Name	String (16)	Player's Username.
			Player UUID	UUID	The UUID of the player logging in. Unused by the vanilla server.

Encryption Response

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: key	Login	Server	Shared Secret	Prefixed Array of Byte	Shared Secret value, encrypted with the server's public key.
			Verify Token	Prefixed Array of Byte	Verify Token value, encrypted with the same public key as the shared secret.

See protocol encryption for details.

Login Plugin Response

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x02 resource: custom_query_answer	Login	Server	Message ID	VarInt	Should match ID from server.
			Data	Prefixed Optional Byte Array (1048576)	Any data, depending on the channel. The length of this array must be inferred from the packet length. Only present if the client understood the request.

Login Acknowledged

Acknowledgement to the Login Success packet sent by the server.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: login_acknowledged	Login	Server	no fields

This packet switches the connection state to configuration.

Cookie Response (login)

Response to a Cookie Request (login) from the server. The vanilla server only accepts responses of up to 5 kiB in size.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x04 resource: cookie_response	Login	Server	Key	Identifier	The identifier of the cookie.
			Payload	Prefixed Optional Prefixed Array (5120) of Byte	The data of the cookie.

Configuration

Clientbound

Cookie Request (configuration)

Requests a cookie that was previously stored.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x00 resource: cookie_request	Configuration	Client	Key		Identifier		The identifier of the cookie.

Clientbound Plugin Message (configuration)

Mods and plugins can use this to send their data. Minecraft itself uses several plugin channels. These internal channels are in the minecraft namespace.

More information on how it works on Dinnerbone's blog. More documentation about internal and popular registered channels are here.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: custom_payload	Configuration	Client	Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (1048576)	Any data. The length of this array must be inferred from the packet length.

In vanilla clients, the maximum data length is 1048576 bytes.

Disconnect (configuration)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x02 resource: disconnect	Configuration	Client	Reason	Text Component	The reason why the player was disconnected.

Finish Configuration

Sent by the server to notify the client that the configuration process has finished. The client answers with Acknowledge Finish Configuration whenever it is ready to continue.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: finish_configuration	Configuration	Client	no fields

This packet switches the connection state to play.

Clientbound Keep Alive (configuration)

The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same payload (see Serverbound Keep Alive). If the client does not respond to a Keep Alive packet within 15 seconds after it was sent, the server kicks the client. Vice versa, if the server does not send any keep-alives for 20 seconds, the client will disconnect and yields a "Timed out" exception.

The vanilla server uses a system-dependent time in milliseconds to generate the keep alive ID value.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x04 resource: keep_alive	Configuration	Client	Keep Alive ID	Long

Ping (configuration)

Packet is not used by the vanilla server. When sent to the client, client responds with a Pong packet with the same id.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x05 resource: ping	Configuration	Client	ID	Int

Reset Chat

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x06 resource: reset_chat	Configuration	Client	no fields

Registry Data

Represents certain registries that are sent from the server and are applied on the client.

See Registry Data for details.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x07 resource: registry_data	Configuration	Client	Registry ID		Identifier
			Entries	Entry ID	Prefixed Array	Identifier
				Data		Prefixed Optional NBT	Entry data.

Remove Resource Pack (configuration)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x08 resource: resource_pack_pop	Configuration	Client	UUID	Prefixed Optional UUID	The UUID of the resource pack to be removed. If not present every resource pack will be removed.

Add Resource Pack (configuration)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x09 resource: resource_pack_push	Configuration	Client	UUID	UUID	The unique identifier of the resource pack.
			URL	String (32767)	The URL to the resource pack.
			Hash	String (40)	A 40 character hexadecimal, case-insensitive SHA-1 hash of the resource pack file. If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth.
			Forced	Boolean	The vanilla client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
			Prompt Message	Prefixed Optional Text Component	This is shown in the prompt making the client accept or decline the resource pack (only if present).

Store Cookie (configuration)

Stores some arbitrary data on the client, which persists between server transfers. The vanilla client only accepts cookies of up to 5 kiB in size.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0A resource: store_cookie	Configuration	Client	Key		Identifier		The identifier of the cookie.
			Payload		Prefixed Array (5120) of Byte		The data of the cookie.

Transfer (configuration)

Notifies the client that it should transfer to the given server. Cookies previously stored are preserved between server transfers.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0B resource: transfer	Configuration	Client	Host		String (32767)		The hostname or IP of the server.
			Port		VarInt		The port of the server.

Feature Flags

Used to enable and disable features, generally experimental ones, on the client.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0C resource: update_enabled_features	Configuration	Client	Feature Flags	Prefixed Array of Identifier

There is one special feature flag, which is in most versions:

• minecraft:vanilla - enables vanilla features

For the other feature flags, which may change between versions, see Experiments#Java_Edition.

Update Tags (configuration)

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0D resource: update_tags	Configuration	Client	Array of tags	Registry	Prefixed Array	Identifier	Registry identifier (Vanilla expects tags for the registries minecraft:block, minecraft:item, minecraft:fluid, minecraft:entity_type, and minecraft:game_event)
				Array of Tag		(See below)

Tag arrays look like:

Field Name		Field Type		Notes
Tags	Tag name	Prefixed Array	Identifier
	Entries		Prefixed Array of VarInt	Numeric IDs of the given type (block, item, etc.). This list replaces the previous list of IDs for the given tag. If some preexisting tags are left unmentioned, a warning is printed.

See Tag on the Minecraft Wiki for more information, including a list of vanilla tags.

Clientbound Known Packs

Informs the client of which data packs are present on the server. The client is expected to respond with its own Serverbound Known Packs packet. The vanilla server does not continue with Configuration until it receives a response.

The vanilla client requires the minecraft:core pack with version 1.21.4 for a normal login sequence. This packet must be sent before the Registry Data packets.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0E resource: select_known_packs	Configuration	Client	Known Packs	Namespace	Prefixed Array	String
				ID		String
				Version		String

Custom Report Details (configuration)

Contains a list of key-value text entries that are included in any crash or disconnection report generated during connection to the server.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0F resource: custom_report_details	Configuration	Client	Details	Title	Prefixed Array (32)	String (128)
				Description		String (4096)

Server Links (configuration)

This packet contains a list of links that the vanilla client will display in the menu available from the pause menu. Link labels can be built-in or custom (i.e., any text).

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x10 resource: server_links	Configuration	Client	Links	Is built-in	Prefixed Array	Boolean	True if Label is an enum (built-in label), false if it's a text component (custom label).
				Label		VarInt Enum / Text Component	See below.
				URL		String	Valid URL.

ID	Name	Notes
0	Bug Report	Displayed on connection error screen; included as a comment in the disconnection report.
1	Community Guidelines
2	Support
3	Status
4	Feedback
5	Community
6	Website
7	Forums
8	News
9	Announcements

Serverbound

Client Information (configuration)

Sent when the player connects, or when settings are changed.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: client_information	Configuration	Server	Locale	String (16)	e.g. en_GB.
			View Distance	Byte	Client-side render distance, in chunks.
			Chat Mode	VarInt Enum	0: enabled, 1: commands only, 2: hidden. See Chat#Client chat mode for more information.
			Chat Colors	Boolean	“Colors” multiplayer setting. The vanilla server stores this value but does nothing with it (see MC-64867). Third-party servers such as Hypixel disable all coloring in chat and system messages when it is false.
			Displayed Skin Parts	Unsigned Byte	Bit mask, see below.
			Main Hand	VarInt Enum	0: Left, 1: Right.
			Enable text filtering	Boolean	Enables filtering of text on signs and written book titles. The vanilla client sets this according to the profanityFilterPreferences.profanityFilterOn account attribute indicated by the /player/attributes Mojang API endpoint. In offline mode it is always false.
			Allow server listings	Boolean	Servers usually list online players, this option should let you not show up in that list.
			Particle Status	VarInt Enum	0: all, 1: decreased, 2: minimal

Displayed Skin Parts flags:

• Bit 0 (0x01): Cape enabled
• Bit 1 (0x02): Jacket enabled
• Bit 2 (0x04): Left Sleeve enabled
• Bit 3 (0x08): Right Sleeve enabled
• Bit 4 (0x10): Left Pants Leg enabled
• Bit 5 (0x20): Right Pants Leg enabled
• Bit 6 (0x40): Hat enabled

The most significant bit (bit 7, 0x80) appears to be unused.

Cookie Response (configuration)

Response to a Cookie Request (configuration) from the server. The vanilla server only accepts responses of up to 5 kiB in size.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: cookie_response	Configuration	Server	Key	Identifier	The identifier of the cookie.
			Payload	Prefixed Optional Prefixed Array (5120) of Byte	The data of the cookie.

Serverbound Plugin Message (configuration)

Mods and plugins can use this to send their data. Minecraft itself uses some plugin channels. These internal channels are in the minecraft namespace.

More documentation on this: https://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/

Note that the length of Data is known only from the packet length, since the packet has no length field of any kind.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x02 resource: custom_payload	Configuration	Server	Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (32767)	Any data, depending on the channel. minecraft: channels are documented here. The length of this array must be inferred from the packet length.

In vanilla server, the maximum data length is 32767 bytes.

Acknowledge Finish Configuration

Sent by the client to notify the server that the configuration process has finished. It is sent in response to the server's Finish Configuration.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: finish_configuration	Configuration	Server	no fields

This packet switches the connection state to play.

Serverbound Keep Alive (configuration)

The server will frequently send out a keep-alive (see Clientbound Keep Alive), each containing a random ID. The client must respond with the same packet.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x04 resource: keep_alive	Configuration	Server	Keep Alive ID	Long

Pong (configuration)

Response to the clientbound packet (Ping) with the same id.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x05 resource: pong	Configuration	Server	ID	Int

Resource Pack Response (configuration)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x06 resource: resource_pack	Configuration	Server	UUID	UUID	The unique identifier of the resource pack received in the Add Resource Pack (configuration) request.
			Result	VarInt Enum	Result ID (see below).

Result can be one of the following values:

ID	Result
0	Successfully downloaded
1	Declined
2	Failed to download
3	Accepted
4	Downloaded
5	Invalid URL
6	Failed to reload
7	Discarded

Serverbound Known Packs

Informs the server of which data packs are present on the client. The client sends this in response to Clientbound Known Packs.

If the client specifies a pack in this packet, the server should omit its contained data from the Registry Data packet.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x07 resource: select_known_packs	Configuration	Server	Known Packs	Namespace	Prefixed Array	String
				ID		String
				Version		String

Play

Clientbound

Bundle Delimiter

The delimiter for a bundle of packets. When received, the client should store every subsequent packet it receives, and wait until another delimiter is received. Once that happens, the client is guaranteed to process every packet in the bundle on the same tick, and the client should stop storing packets.

As of 1.20.6, the vanilla server only uses this to ensure Spawn Entity and associated packets used to configure the entity happen on the same tick. Each entity gets a separate bundle.

The vanilla client doesn't allow more than 4096 packets in the same bundle.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: bundle_delimiter	Play	Client	no fields

Spawn Entity

Sent by the server when an entity (aside from Experience Orb) is created.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: add_entity	Play	Client	Entity ID	VarInt	A unique integer ID mostly used in the protocol to identify the entity.
			Entity UUID	UUID	A unique identifier that is mostly used in persistence and places where the uniqueness matters more.
			Type	VarInt	ID in the minecraft:entity_type registry (see "type" field in Entity metadata#Entities).
			X	Double
			Y	Double
			Z	Double
			Pitch	Angle	To get the real pitch, you must divide this by (256.0F / 360.0F)
			Yaw	Angle	To get the real yaw, you must divide this by (256.0F / 360.0F)
			Head Yaw	Angle	Only used by living entities, where the head of the entity may differ from the general body rotation.
			Data	VarInt	Meaning dependent on the value of the Type field, see Object Data for details.
			Velocity X	Short	Same units as Set Entity Velocity.
			Velocity Y	Short
			Velocity Z	Short

When in online mode, the UUIDs must be valid and have valid skin blobs. In offline mode, the vanilla server uses UUID v3 and chooses the player's UUID by using the String OfflinePlayer:<player name>, encoding it in UTF-8 (and case-sensitive), then processes it with UUID.nameUUIDFromBytes.

For NPCs UUID v2 should be used. Note:

<+Grum> i will never confirm this as a feature you know that :)

In an example UUID, xxxxxxxx-xxxx-Yxxx-xxxx-xxxxxxxxxxxx, the UUID version is specified by Y. So, for UUID v3, Y will always be 3, and for UUID v2, Y will always be 2.

Spawn Experience Orb

Spawns one or more experience orbs.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x02 resource: add_experience_orb	Play	Client	Entity ID	VarInt
			X	Double
			Y	Double
			Z	Double
			Count	Short	The amount of experience this orb will reward once collected.

Entity Animation

Sent whenever an entity should change animation.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: animate	Play	Client	Entity ID	VarInt	Player ID.
			Animation	Unsigned Byte	Animation ID (see below).

Animation can be one of the following values:

ID	Animation
0	Swing main arm
2	Leave bed
3	Swing offhand
4	Critical effect
5	Magic critical effect

Award Statistics

Sent as a response to Client Status (id 1). Will only send the changed values if previously requested.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x04 resource: award_stats	Play	Client	Statistic	Category ID	Prefixed Array	VarInt	See below.
				Statistic ID		VarInt	See below.
				Value		VarInt	The amount to set it to.

Categories (these are namespaced, but with : replaced with .):

Name	ID	Registry
minecraft.mined	0	Blocks
minecraft.crafted	1	Items
minecraft.used	2	Items
minecraft.broken	3	Items
minecraft.picked_up	4	Items
minecraft.dropped	5	Items
minecraft.killed	6	Entities
minecraft.killed_by	7	Entities
minecraft.custom	8	Custom

Blocks, Items, and Entities use block (not block state), item, and entity ids.

Custom has the following (unit only matters for clients):

Name	ID	Unit
minecraft.leave_game	0	None
minecraft.play_time	1	Time
minecraft.total_world_time	2	Time
minecraft.time_since_death	3	Time
minecraft.time_since_rest	4	Time
minecraft.sneak_time	5	Time
minecraft.walk_one_cm	6	Distance
minecraft.crouch_one_cm	7	Distance
minecraft.sprint_one_cm	8	Distance
minecraft.walk_on_water_one_cm	9	Distance
minecraft.fall_one_cm	10	Distance
minecraft.climb_one_cm	11	Distance
minecraft.fly_one_cm	12	Distance
minecraft.walk_under_water_one_cm	13	Distance
minecraft.minecart_one_cm	14	Distance
minecraft.boat_one_cm	15	Distance
minecraft.pig_one_cm	16	Distance
minecraft.horse_one_cm	17	Distance
minecraft.aviate_one_cm	18	Distance
minecraft.swim_one_cm	19	Distance
minecraft.strider_one_cm	20	Distance
minecraft.jump	21	None
minecraft.drop	22	None
minecraft.damage_dealt	23	Damage
minecraft.damage_dealt_absorbed	24	Damage
minecraft.damage_dealt_resisted	25	Damage
minecraft.damage_taken	26	Damage
minecraft.damage_blocked_by_shield	27	Damage
minecraft.damage_absorbed	28	Damage
minecraft.damage_resisted	29	Damage
minecraft.deaths	30	None
minecraft.mob_kills	31	None
minecraft.animals_bred	32	None
minecraft.player_kills	33	None
minecraft.fish_caught	34	None
minecraft.talked_to_villager	35	None
minecraft.traded_with_villager	36	None
minecraft.eat_cake_slice	37	None
minecraft.fill_cauldron	38	None
minecraft.use_cauldron	39	None
minecraft.clean_armor	40	None
minecraft.clean_banner	41	None
minecraft.clean_shulker_box	42	None
minecraft.interact_with_brewingstand	43	None
minecraft.interact_with_beacon	44	None
minecraft.inspect_dropper	45	None
minecraft.inspect_hopper	46	None
minecraft.inspect_dispenser	47	None
minecraft.play_noteblock	48	None
minecraft.tune_noteblock	49	None
minecraft.pot_flower	50	None
minecraft.trigger_trapped_chest	51	None
minecraft.open_enderchest	52	None
minecraft.enchant_item	53	None
minecraft.play_record	54	None
minecraft.interact_with_furnace	55	None
minecraft.interact_with_crafting_table	56	None
minecraft.open_chest	57	None
minecraft.sleep_in_bed	58	None
minecraft.open_shulker_box	59	None
minecraft.open_barrel	60	None
minecraft.interact_with_blast_furnace	61	None
minecraft.interact_with_smoker	62	None
minecraft.interact_with_lectern	63	None
minecraft.interact_with_campfire	64	None
minecraft.interact_with_cartography_table	65	None
minecraft.interact_with_loom	66	None
minecraft.interact_with_stonecutter	67	None
minecraft.bell_ring	68	None
minecraft.raid_trigger	69	None
minecraft.raid_win	70	None
minecraft.interact_with_anvil	71	None
minecraft.interact_with_grindstone	72	None
minecraft.target_hit	73	None
minecraft.interact_with_smithing_table	74	None

Units:

• None: just a normal number (formatted with 0 decimal places)
• Damage: value is 10 times the normal amount
• Distance: a distance in centimeters (hundredths of blocks)
• Time: a time span in ticks

Acknowledge Block Change

Acknowledges a user-initiated block change. After receiving this packet, the client will display the block state sent by the server instead of the one predicted by the client.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x05 resource: block_changed_ack	Play	Client	Sequence ID	VarInt	Represents the sequence to acknowledge, this is used for properly syncing block changes to the client after interactions.

Set Block Destroy Stage

0–9 are the displayable destroy stages and each other number means that there is no animation on this coordinate.

Block break animations can still be applied on air; the animation will remain visible although there is no block being broken. However, if this is applied to a transparent block, odd graphical effects may happen, including water losing its transparency. (An effect similar to this can be seen in normal gameplay when breaking ice blocks)

If you need to display several break animations at the same time you have to give each of them a unique Entity ID. The entity ID does not need to correspond to an actual entity on the client. It is valid to use a randomly generated number.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x06 resource: block_destruction	Play	Client	Entity ID	VarInt	The ID of the entity breaking the block.
			Location	Position	Block Position.
			Destroy Stage	Unsigned Byte	0–9 to set it, any other value to remove it.

Block Entity Data

Sets the block entity associated with the block at the given location.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x07 resource: block_entity_data	Play	Client	Location	Position
			Type	VarInt	The type of the block entity
			NBT Data	NBT	Data to set. May be a TAG_END (0), in which case the block entity at the given location is removed (though this is not required since the client will remove the block entity automatically on chunk unload or block removal).

Block Action

This packet is used for a number of actions and animations performed by blocks, usually non-persistent. The client ignores the provided block type and instead uses the block state in their world.

See Block Actions for a list of values.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x08 resource: block_event	Play	Client	Location	Position	Block coordinates.
			Action ID (Byte 1)	Unsigned Byte	Varies depending on block — see Block Actions.
			Action Parameter (Byte 2)	Unsigned Byte	Varies depending on block — see Block Actions.
			Block Type	VarInt	The block type ID for the block. This value is unused by the vanilla client, as it will infer the type of block based on the given position.

Block Update

Fired whenever a block is changed within the render distance.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x09 resource: block_update	Play	Client	Location	Position	Block Coordinates.
			Block ID	VarInt	The new block state ID for the block as given in the block state registry.

Boss Bar

Packet ID	State	Bound To	Field Name		Field Type	Notes
protocol: 0x0A resource: boss_event	Play	Client	UUID		UUID	Unique ID for this bar.
			Action		VarInt Enum	Determines the layout of the remaining packet.
			Action	Field Name
			0: add	Title	Text Component
				Health	Float	From 0 to 1. Values greater than 1 do not crash a vanilla client, and start rendering part of a second health bar at around 1.5.
				Color	VarInt Enum	Color ID (see below).
				Division	VarInt Enum	Type of division (see below).
				Flags	Unsigned Byte	Bit mask. 0x01: should darken sky, 0x02: is dragon bar (used to play end music), 0x04: create fog (previously was also controlled by 0x02).
			1: remove	no fields	no fields	Removes this boss bar.
			2: update health	Health	Float	as above
			3: update title	Title	Text Component
			4: update style	Color	VarInt Enum	Color ID (see below).
				Dividers	VarInt Enum	as above
			5: update flags	Flags	Unsigned Byte	as above

ID	Color
0	Pink
1	Blue
2	Red
3	Green
4	Yellow
5	Purple
6	White

ID	Type of division
0	No division
1	6 notches
2	10 notches
3	12 notches
4	20 notches

Change Difficulty

Changes the difficulty setting in the client's option menu

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0B resource: change_difficulty	Play	Client	Difficulty	Unsigned Byte Enum	0: peaceful, 1: easy, 2: normal, 3: hard.
			Difficulty locked?	Boolean

Chunk Batch Finished

Marks the end of a chunk batch. The vanilla client marks the time it receives this packet and calculates the elapsed duration since the beginning of the chunk batch. The server uses this duration and the batch size received in this packet to estimate the number of milliseconds elapsed per chunk received. This value is then used to calculate the desired number of chunks per tick through the formula 25 / millisPerChunk, which is reported to the server through Chunk Batch Received. This likely uses 25 instead of the normal tick duration of 50 so chunk processing will only use half of the client's and network's bandwidth.

The vanilla client uses the samples from the latest 15 batches to estimate the milliseconds per chunk number.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0C resource: chunk_batch_finished	Play	Client	Batch size	VarInt	Number of chunks.

Chunk Batch Start

Marks the start of a chunk batch. The vanilla client marks and stores the time it receives this packet.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0D resource: chunk_batch_start	Play	Client	no fields

Chunk Biomes

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x0E resource: chunks_biomes	Play	Client	Chunk biome data	Chunk Z	Prefixed Array	Int	Chunk coordinate (block coordinate divided by 16, rounded down)
				Chunk X		Int	Chunk coordinate (block coordinate divided by 16, rounded down)
				Data		Prefixed Array of Byte	Chunk data structure, with sections containing only the Biomes field

Note: The order of X and Z is inverted, because the client reads them as one big-endian Long, with Z being the upper 32 bits.

Clear Titles

Clear the client's current title information, with the option to also reset it.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0F resource: clear_titles	Play	Client	Reset	Boolean

Command Suggestions Response

The server responds with a list of auto-completions of the last word sent to it. In the case of regular chat, this is a player username. Command names and parameters are also supported. The client sorts these alphabetically before listing them.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x10 resource: command_suggestions	Play	Client	ID		VarInt		Transaction ID.
			Start		VarInt		Start of the text to replace.
			Length		VarInt		Length of the text to replace.
			Matches	Match	Prefixed Array	String (32767)	One eligible value to insert, note that each command is sent separately instead of in a single string, hence the need for Count. Note that for instance this doesn't include a leading / on commands.
				Tooltip		Prefixed Optional Text Component	Tooltip to display.

Commands

Lists all of the commands on the server, and how they are parsed.

This is a directed graph, with one root node. Each redirect or child node must refer only to nodes that have already been declared.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x11 resource: commands	Play	Client	Nodes	Prefixed Array of Node	An array of nodes.
			Root index	VarInt	Index of the root node in the previous array.

For more information on this packet, see the Command Data article.

Close Container

This packet is sent from the server to the client when a window is forcibly closed, such as when a chest is destroyed while it's open. The vanilla client disregards the provided window ID and closes any active window.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x12 resource: container_close	Play	Client	Window ID	VarInt	This is the ID of the window that was closed. 0 for inventory.

Set Container Content

The inventory slots

Replaces the contents of a container window. Sent by the server upon initialization of a container window or the player's inventory, and in response to state ID mismatches (see #Click Container).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x13 resource: container_set_content	Play	Client	Window ID	VarInt	The ID of window which items are being sent for. 0 for player inventory. The client ignores any packets targeting a Window ID other than the current one. However, an exception is made for the player inventory, which may be targeted at any time. (The vanilla server does not appear to utilize this special case.)
			State ID	VarInt	A server-managed sequence number used to avoid desynchronization; see #Click Container.
			Slot Data	Prefixed Array of Slot
			Carried Item	Slot	Item being dragged with the mouse.

See inventory windows for further information about how slots are indexed. Use Open Screen to open the container on the client.

Set Container Property

This packet is used to inform the client that part of a GUI window should be updated.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x14 resource: container_set_data	Play	Client	Window ID	VarInt
			Property	Short	The property to be updated, see below.
			Value	Short	The new value for the property, see below.

The meaning of the Property field depends on the type of the window. The following table shows the known combinations of window type and property, and how the value is to be interpreted.

Window type	Property	Value
Furnace	0: Fire icon (fuel left)	counting from fuel burn time down to 0 (in-game ticks)
	1: Maximum fuel burn time	fuel burn time or 0 (in-game ticks)
	2: Progress arrow	counting from 0 to maximum progress (in-game ticks)
	3: Maximum progress	always 200 on the vanilla server
Enchantment Table	0: Level requirement for top enchantment slot	The enchantment's xp level requirement
	1: Level requirement for middle enchantment slot
	2: Level requirement for bottom enchantment slot
	3: The enchantment seed	Used for drawing the enchantment names (in SGA) clientside. The same seed is used to calculate enchantments, but some of the data isn't sent to the client to prevent easily guessing the entire list (the seed value here is the regular seed bitwise and 0xFFFFFFF0).
	4: Enchantment ID shown on mouse hover over top enchantment slot	The enchantment id (set to -1 to hide it), see below for values
	5: Enchantment ID shown on mouse hover over middle enchantment slot
	6: Enchantment ID shown on mouse hover over bottom enchantment slot
	7: Enchantment level shown on mouse hover over the top slot	The enchantment level (1 = I, 2 = II, 6 = VI, etc.), or -1 if no enchant
	8: Enchantment level shown on mouse hover over the middle slot
	9: Enchantment level shown on mouse hover over the bottom slot
Beacon	0: Power level	0-4, controls what effect buttons are enabled
	1: First potion effect	Potion effect ID for the first effect, or -1 if no effect
	2: Second potion effect	Potion effect ID for the second effect, or -1 if no effect
Anvil	0: Repair cost	The repair's cost in xp levels
Brewing Stand	0: Brew time	0 – 400, with 400 making the arrow empty, and 0 making the arrow full
	1: Fuel time	0 - 20, with 0 making the arrow empty, and 20 making the arrow full
Stonecutter	0: Selected recipe	The index of the selected recipe. -1 means none is selected.
Loom	0: Selected pattern	The index of the selected pattern. 0 means none is selected, 0 is also the internal id of the "base" pattern.
Lectern	0: Page number	The current page number, starting from 0.

For an enchanting table, the following numerical IDs are used:

Numerical ID	Enchantment ID	Enchantment Name
0	minecraft:protection	Protection
1	minecraft:fire_protection	Fire Protection
2	minecraft:feather_falling	Feather Falling
3	minecraft:blast_protection	Blast Protection
4	minecraft:projectile_protection	Projectile Protection
5	minecraft:respiration	Respiration
6	minecraft:aqua_affinity	Aqua Affinity
7	minecraft:thorns	Thorns
8	minecraft:depth_strider	Depth Strider
9	minecraft:frost_walker	Frost Walker
10	minecraft:binding_curse	Curse of Binding
11	minecraft:soul_speed	Soul Speed
12	minecraft:swift_sneak	Swift Sneak
13	minecraft:sharpness	Sharpness
14	minecraft:smite	Smite
15	minecraft:bane_of_arthropods	Bane of Arthropods
16	minecraft:knockback	Knockback
17	minecraft:fire_aspect	Fire Aspect
18	minecraft:looting	Looting
19	minecraft:sweeping_edge	Sweeping Edge
20	minecraft:efficiency	Efficiency
21	minecraft:silk_touch	Silk Touch
22	minecraft:unbreaking	Unbreaking
23	minecraft:fortune	Fortune
24	minecraft:power	Power
25	minecraft:punch	Punch
26	minecraft:flame	Flame
27	minecraft:infinity	Infinity
28	minecraft:luck_of_the_sea	Luck of the Sea
29	minecraft:lure	Lure
30	minecraft:loyalty	Loyalty
31	minecraft:impaling	Impaling
32	minecraft:riptide	Riptide
33	minecraft:channeling	Channeling
34	minecraft:multishot	Multishot
35	minecraft:quick_charge	Quick Charge
36	minecraft:piercing	Piercing
37	minecraft:density	Density
38	minecraft:breach	Breach
39	minecraft:wind_burst	Wind Burst
40	minecraft:mending	Mending
41	minecraft:vanishing_curse	Curse of Vanishing

Set Container Slot

Sent by the server when an item in a slot (in a window) is added/removed.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x15 resource: container_set_slot	Play	Client	Window ID	VarInt	The window which is being updated. 0 for player inventory. The client ignores any packets targeting a Window ID other than the current one; see below for exceptions.
			State ID	VarInt	A server-managed sequence number used to avoid desynchronization; see #Click Container.
			Slot	Short	The slot that should be updated.
			Slot Data	Slot

If Window ID is 0, the hotbar and offhand slots (slots 36 through 45) may be updated even when a different container window is open. (The vanilla server does not appear to utilize this special case.) Updates are also restricted to those slots when the player is looking at a creative inventory tab other than the survival inventory. (The vanilla server does not handle this restriction in any way, leading to MC-242392.)

If Window ID is -1, the item being dragged with the mouse is set. In this case, State ID and Slot are ignored.

If Window ID is -2, any slot in the player's inventory can be updated irrespective of the current container window. In this case, State ID is ignored, and the vanilla server uses a bogus value of 0. Used by the vanilla server to implement the #Pick Item functionality.

When a container window is open, the server never sends updates targeting Window ID 0—all of the window types include slots for the player inventory. The client must automatically apply changes targeting the inventory portion of a container window to the main inventory; the server does not resend them for ID 0 when the window is closed. However, since the armor and offhand slots are only present on ID 0, updates to those slots occurring while a window is open must be deferred by the server until the window's closure.

Cookie Request (play)

Requests a cookie that was previously stored.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x16 resource: cookie_request	Play	Client	Key		Identifier		The identifier of the cookie.

Set Cooldown

Applies a cooldown period to all items with the given type. Used by the vanilla server with enderpearls. This packet should be sent when the cooldown starts and also when the cooldown ends (to compensate for lag), although the client will end the cooldown automatically. Can be applied to any item, note that interactions still get sent to the server with the item but the client does not play the animation nor attempt to predict results (i.e block placing).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x17 resource: cooldown	Play	Client	Item ID	VarInt	Numeric ID of the item to apply a cooldown to.
			Cooldown Ticks	VarInt	Number of ticks to apply a cooldown for, or 0 to clear the cooldown.

Chat Suggestions

Unused by the vanilla server. Likely provided for custom servers to send chat message completions to clients.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x18 resource: custom_chat_completions	Play	Client	Action	VarInt Enum	0: Add, 1: Remove, 2: Set
			Entries	Prefixed Array of String (32767)

Clientbound Plugin Message (play)

Mods and plugins can use this to send their data. Minecraft itself uses several plugin channels. These internal channels are in the minecraft namespace.

More information on how it works on Dinnerbone's blog. More documentation about internal and popular registered channels are here.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x19 resource: custom_payload	Play	Client	Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (1048576)	Any data. The length of this array must be inferred from the packet length.

In vanilla clients, the maximum data length is 1048576 bytes.

Damage Event

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x1A resource: damage_event	Play	Client
			Entity ID		VarInt		The ID of the entity taking damage
			Source Type ID		VarInt		The type of damage in the minecraft:damage_type registry, defined by the Registry Data packet.
			Source Cause ID		VarInt		The ID + 1 of the entity responsible for the damage, if present. If not present, the value is 0
			Source Direct ID		VarInt		The ID + 1 of the entity that directly dealt the damage, if present. If not present, the value is 0. If this field is present: and damage was dealt indirectly, such as by the use of a projectile, this field will contain the ID of such projectile; and damage was dealt dirctly, such as by manually attacking, this field will contain the same value as Source Cause ID.
			Has Source Position		Boolean		Indicates the presence of the three following fields. The vanilla server sends the Source Position when the damage was dealt by the /damage command and a position was specified
			Source Position X		Optional Double		Only present if Has Source Position is true
			Source Position Y		Optional Double		Only present if Has Source Position is true
			Source Position Z		Optional Double		Only present if Has Source Position is true

Debug Sample

Sample data that is sent periodically after the client has subscribed with Debug Sample Subscription.

The vanilla server only sends debug samples to players that are server operators.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1B resource: debug_sample	Play	Client	Sample	Prefixed Array of Long	Array of type-dependent samples.
			Sample Type	VarInt Enum	See below.

Types:

Id	Name	Description
0	Tick time	Four different tick-related metrics, each one represented by one long on the array. They are measured in nano-seconds, and are as follows: 0: Full tick time: Aggregate of the three times below; 1: Server tick time: Main server tick logic; 2: Tasks time: Tasks scheduled to execute after the main logic; 3: Idle time: Time idling to complete the full 50ms tick cycle. Note that the vanilla client calculates the timings used for min/max/average display by subtracting the idle time from the full tick time. This can cause the displayed values to go negative if the idle time is (nonsensically) greater than the full tick time.

Delete Message

Removes a message from the client's chat. This only works for messages with signatures, system messages cannot be deleted with this packet.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1C resource: delete_chat	Play	Client	Message ID	VarInt	The message Id + 1, used for validating message signature. The next field is present only when value of this field is equal to 0.
			Signature	Optional Byte Array (256)	The previous message's signature. Always 256 bytes and not length-prefixed.

Disconnect (play)

Sent by the server before it disconnects a client. The client assumes that the server has already closed the connection by the time the packet arrives.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1D resource: disconnect	Play	Client	Reason	Text Component	Displayed to the client when the connection terminates.

Disguised Chat Message

Sends the client a chat message, but without any message signing information.

The vanilla server uses this packet when the console is communicating with players through commands, such as /say, /tell, /me, among others.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1E resource: disguised_chat	Play	Client	Message	Text Component	This is used as the content parameter when formatting the message on the client.
			Chat Type	VarInt	The type of chat in the minecraft:chat_type registry, defined by the Registry Data packet.
			Sender Name	Text Component	The name of the one sending the message, usually the sender's display name. This is used as the sender parameter when formatting the message on the client.
			Target Name	Prefixed Optional Text Component	The name of the one receiving the message, usually the receiver's display name. This is used as the target parameter when formatting the message on the client.

Entity Event

Entity statuses generally trigger an animation for an entity. The available statuses vary by the entity's type (and are available to subclasses of that type as well).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1F resource: entity_event	Play	Client	Entity ID	Int
			Entity Status	Byte Enum	See Entity statuses for a list of which statuses are valid for each type of entity.

Teleport Entity

This packet is sent by the server when an entity moves more than 8 blocks.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x20 resource: entity_position_sync	Play	Client	Entity ID	VarInt
			X	Double
			Y	Double
			Z	Double
			Velocity X	Double
			Velocity Y	Double
			Velocity Z	Double
			Yaw	Float	Rotation on the X axis, in degrees.
			Pitch	Float	Rotation on the Y axis, in degrees.
			On Ground	Boolean

Explosion

Sent when an explosion occurs (creepers, TNT, and ghast fireballs).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x21 resource: explode	Play	Client	X	Double
			Y	Double
			Z	Double
			Has Player Velocity	Boolean
			Player Velocity X	Optional Double	X velocity of the player being pushed by the explosion. Only present if Has Player Velocity is true.
			Player Velocity Y	Optional Float	Y velocity of the player being pushed by the explosion. Only present if Has Player Velocity is true.
			Player Velocity Z	Optional Float	Z velocity of the player being pushed by the explosion. Only present if Has Player Velocity is true.
			Explosion Particle ID	VarInt	The particle ID listed in Particles.
			Explosion Particle Data	Varies	Particle data as specified in Particles.
			Explosion Sound	ID or Sound Event	ID in the minecraft:sound_event registry, or an inline definition.

Unload Chunk

Tells the client to unload a chunk column.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x22 resource: forget_level_chunk	Play	Client	Chunk Z	Int	Block coordinate divided by 16, rounded down.
			Chunk X	Int	Block coordinate divided by 16, rounded down.

Note: The order is inverted, because the client reads this packet as one big-endian Long, with Z being the upper 32 bits.

It is legal to send this packet even if the given chunk is not currently loaded.

Game Event

Used for a wide variety of game events, from weather to bed use to game mode to demo messages.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x23 resource: game_event	Play	Client	Event	Unsigned Byte	See below.
			Value	Float	Depends on Event.

Events:

Event	Effect	Value
0	No respawn block available	Note: Displays message 'block.minecraft.spawn.not_valid' (You have no home bed or charged respawn anchor, or it was obstructed) to the player.
1	Begin raining
2	End raining
3	Change game mode	0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
4	Win game	0: Just respawn player. 1: Roll the credits and respawn player. Note that 1 is only sent by vanilla server when player has not yet achieved advancement "The end?", else 0 is sent.
5	Demo event	0: Show welcome to demo screen. 101: Tell movement controls. 102: Tell jump control. 103: Tell inventory control. 104: Tell that the demo is over and print a message about how to take a screenshot.
6	Arrow hit player	Note: Sent when any player is struck by an arrow.
7	Rain level change	Note: Seems to change both sky color and lighting. Rain level ranging from 0 to 1.
8	Thunder level change	Note: Seems to change both sky color and lighting (same as Rain level change, but doesn't start rain). It also requires rain to render by vanilla client. Thunder level ranging from 0 to 1.
9	Play pufferfish sting sound
10	Play elder guardian mob appearance (effect and sound)
11	Enable respawn screen	0: Enable respawn screen. 1: Immediately respawn (sent when the doImmediateRespawn gamerule changes).
12	Limited crafting	0: Disable limited crafting. 1: Enable limited crafting (sent when the doLimitedCrafting gamerule changes).
13	Start waiting for level chunks	Instructs the client to begin the waiting process for the level chunks. Sent by the server after the level is cleared on the client and is being re-sent (either during the first, or subsequent reconfigurations).

Open Horse Screen

This packet is used exclusively for opening the horse GUI. Open Screen is used for all other GUIs. The client will not open the inventory if the Entity ID does not point to an horse-like animal.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x24 resource: horse_screen_open	Play	Client	Window ID	VarInt	Same as the field of Open Screen.
			Inventory columns count	VarInt	How many columns of horse inventory slots exist in the GUI, 3 slots per column.
			Entity ID	Int	The "owner" entity of the GUI. The client should close the GUI if the owner entity dies or is cleared.

Hurt Animation

Plays a bobbing animation for the entity receiving damage.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x25 resource: hurt_animation	Play	Client	Entity ID	VarInt	The ID of the entity taking damage
			Yaw	Float	The direction the damage is coming from in relation to the entity

Initialize World Border

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x26 resource: initialize_border	Play	Client	X	Double
			Z	Double
			Old Diameter	Double	Current length of a single side of the world border, in meters.
			New Diameter	Double	Target length of a single side of the world border, in meters.
			Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that vanilla server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
			Warning Blocks	VarInt	In meters.
			Warning Time	VarInt	In seconds as set by /worldborder warning time.

The vanilla client determines how solid to display the warning by comparing to whichever is higher, the warning distance or whichever is lower, the distance from the current diameter to the target diameter or the place the border will be after warningTime seconds. In pseudocode:

distance = max(min(resizeSpeed * 1000 * warningTime, abs(targetDiameter - currentDiameter)), warningDistance);
if (playerDistance < distance) {
    warning = 1.0 - playerDistance / distance;
} else {
    warning = 0.0;
}

Clientbound Keep Alive (play)

The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same payload (see Serverbound Keep Alive). If the client does not respond to a Keep Alive packet within 15 seconds after it was sent, the server kicks the client. Vice versa, if the server does not send any keep-alives for 20 seconds, the client will disconnect and yields a "Timed out" exception.

The vanilla server uses a system-dependent time in milliseconds to generate the keep alive ID value.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x27 resource: keep_alive	Play	Client	Keep Alive ID	Long

Chunk Data and Update Light

Sent when a chunk comes into the client's view distance, specifying its terrain, lighting and block entities.

The chunk must be within the view area previously specified with Set Center Chunk; see that packet for details.

It is not strictly necessary to send all block entities in this packet; it is still legal to send them with Block Entity Data later.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x28 resource: level_chunk_with_light	Play	Client	Chunk X	Int	Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z	Int	Chunk coordinate (block coordinate divided by 16, rounded down)
			Data	Chunk Data
			Light	Light Data

Unlike the Update Light packet which uses the same format, setting the bit corresponding to a section to 0 in both of the block light or sky light masks does not appear to be useful, and the results in testing have been highly inconsistent.

World Event

Sent when a client is to play a sound or particle effect.

By default, the Minecraft client adjusts the volume of sound effects based on distance. The final boolean field is used to disable this, and instead the effect is played from 2 blocks away in the correct direction. Currently this is only used for effect 1023 (wither spawn), effect 1028 (enderdragon death), and effect 1038 (end portal opening); it is ignored on other effects.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x29 resource: level_event	Play	Client	Event	Int	The event, see below.
			Location	Position	The location of the event.
			Data	Int	Extra data for certain events, see below.
			Disable Relative Volume	Boolean	See above.

Events:

ID	Name	Data
Sound
1000	Dispenser dispenses
1001	Dispenser fails to dispense
1002	Dispenser shoots
1004	Firework shot
1009	Fire extinguished
1010	Play record	An ID in the minecraft:item registry, corresponding to a record item. If the ID doesn't correspond to a record, the packet is ignored. Any record already being played at the given location is overwritten. See Data Generators for information on item IDs.
1011	Stop record
1015	Ghast warns
1016	Ghast shoots
1017	Ender dragon shoots
1018	Blaze shoots
1019	Zombie attacks wooden door
1020	Zombie attacks iron door
1021	Zombie breaks wooden door
1022	Wither breaks block
1023	Wither spawned
1024	Wither shoots
1025	Bat takes off
1026	Zombie infects
1027	Zombie villager converted
1028	Ender dragon dies
1029	Anvil destroyed
1030	Anvil used
1031	Anvil lands
1032	Portal travel
1033	Chorus flower grows
1034	Chorus flower dies
1035	Brewing stand brews
1038	End portal created
1039	Phantom bites
1040	Zombie converts to drowned
1041	Husk converts to zombie by drowning
1042	Grindstone used
1043	Book page turned
1044	Smithing table used
1045	Pointed dripstone landing
1046	Lava dripping on cauldron from dripstone
1047	Water dripping on cauldron from dripstone
1048	Skeleton converts to stray
1049	Crafter successfully crafts item
1050	Crafter fails to craft item
Particle
1500	Composter composts
1501	Lava converts block (either water to stone, or removes existing blocks such as torches)
1502	Redstone torch burns out
1503	Ender eye placed in end portal frame
1504	Fluid drips from dripstone
1505	Bone meal particles and sound	How many particles to spawn.
2000	Dispenser activation smoke	Direction, see below.
2001	Block break + block break sound	Block state ID (see Chunk Format#Block state registry).
2002	Splash potion. Particle effect + glass break sound.	RGB color as an integer (e.g. 8364543 for #7FA1FF).
2003	Eye of ender entity break animation — particles and sound
2004	Spawner spawns mob: smoke + flames
2006	Dragon breath
2007	Instant splash potion. Particle effect + glass break sound.	RGB color as an integer (e.g. 8364543 for #7FA1FF).
2008	Ender dragon destroys block
2009	Wet sponge vaporizes
2010	Crafter activation smoke	Direction, see below.
2011	Bee fertilizes plant	How many particles to spawn.
2012	Turtle egg placed	How many particles to spawn.
2013	Smash attack (mace)	How many particles to spawn.
3000	End gateway spawns
3001	Ender dragon resurrected
3002	Electric spark
3003	Copper apply wax
3004	Copper remove wax
3005	Copper scrape oxidation
3006	Sculk charge
3007	Sculk shrieker shriek
3008	Block finished brushing	Block state ID (see Chunk Format#Block state registry)
3009	Sniffer egg cracks	If 1, 3-6, if any other number, 1-3 particles will be spawned.
3011	Trial spawner spawns mob (at spawner)
3012	Trial spawner spawns mob (at spawn location)
3013	Trial spawner detects player	Number of players nearby
3014	Trial spawner ejects item
3015	Vault activates
3016	Vault deactivates
3017	Vault ejects item
3018	Cobweb weaved
3019	Ominous trial spawner detects player	Number of players nearby
3020	Trial spawner turns ominous	If 0, the sound will be played at 0.3 volume. Otherwise, it is played at full volume.
3021	Ominous item spawner spawns item

Smoke directions:

ID	Direction
0	Down
1	Up
2	North
3	South
4	West
5	East

Particle

Displays the named particle

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2A resource: level_particles	Play	Client	Long Distance	Boolean	If true, particle distance increases from 256 to 65536.
			Always Visible	Boolean	Whether this particle should always be visible.
			X	Double	X position of the particle.
			Y	Double	Y position of the particle.
			Z	Double	Z position of the particle.
			Offset X	Float	This is added to the X position after being multiplied by random.nextGaussian().
			Offset Y	Float	This is added to the Y position after being multiplied by random.nextGaussian().
			Offset Z	Float	This is added to the Z position after being multiplied by random.nextGaussian().
			Max Speed	Float
			Particle Count	Int	The number of particles to create.
			Particle ID	VarInt	The particle ID listed in Particles.
			Data	Varies	Particle data as specified in Particles.

Update Light

Updates light levels for a chunk. See Light for information on how lighting works in Minecraft.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2B resource: light_update	Play	Client	Chunk X	VarInt	Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z	VarInt	Chunk coordinate (block coordinate divided by 16, rounded down)
			Data	Light Data

A bit will never be set in both the block light mask and the empty block light mask, though it may be present in neither of them (if the block light does not need to be updated for the corresponding chunk section). The same applies to the sky light mask and the empty sky light mask.

Login (play)

See protocol encryption for information on logging in.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2C resource: login	Play	Client	Entity ID	Int	The player's Entity ID (EID).
			Is hardcore	Boolean
			Dimension Names	Prefixed Array of Identifier	Identifiers for all dimensions on the server.
			Max Players	VarInt	Was once used by the client to draw the player list, but now is ignored.
			View Distance	VarInt	Render distance (2-32).
			Simulation Distance	VarInt	The distance that the client will process specific things, such as entities.
			Reduced Debug Info	Boolean	If true, a vanilla client shows reduced information on the debug screen. For servers in development, this should almost always be false.
			Enable respawn screen	Boolean	Set to false when the doImmediateRespawn gamerule is true.
			Do limited crafting	Boolean	Whether players can only craft recipes they have already unlocked. Currently unused by the client.
			Dimension Type	VarInt	The ID of the type of dimension in the minecraft:dimension_type registry, defined by the Registry Data packet.
			Dimension Name	Identifier	Name of the dimension being spawned into.
			Hashed seed	Long	First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
			Game mode	Unsigned Byte	0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
			Previous Game mode	Byte	-1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous game mode. Vanilla client uses this for the debug (F3 + N & F3 + F4) game mode switch. (More information needed)
			Is Debug	Boolean	True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
			Is Flat	Boolean	True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
			Has death location	Boolean	If true, then the next two fields are present.
			Death dimension name	Optional Identifier	Name of the dimension the player died in.
			Death location	Optional Position	The location that the player died at.
			Portal cooldown	VarInt	The number of ticks until the player can use the portal again.
			Sea level	VarInt
			Enforces Secure Chat	Boolean

Map Data

Updates a rectangular area on a map item.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x2D resource: map_item_data	Play	Client	Map ID		VarInt		Map ID of the map being modified
			Scale		Byte		From 0 for a fully zoomed-in map (1 block per pixel) to 4 for a fully zoomed-out map (16 blocks per pixel)
			Locked		Boolean		True if the map has been locked in a cartography table
			Icon	Type	Prefixed Optional Prefixed Array	VarInt Enum	See below
				X		Byte	Map coordinates: -128 for furthest left, +127 for furthest right
				Z		Byte	Map coordinates: -128 for highest, +127 for lowest
				Direction		Byte	0-15
				Display Name		Prefixed Optional Text Component
			Color Patch	Columns	Unsigned Byte		Number of columns updated
				Rows	Optional Unsigned Byte		Only if Columns is more than 0; number of rows updated
				X	Optional Unsigned Byte		Only if Columns is more than 0; x offset of the westernmost column
				Z	Optional Unsigned Byte		Only if Columns is more than 0; z offset of the northernmost row
				Data	Optional Prefixed Array of Unsigned Byte		Only if Columns is more than 0; see Map item format

For icons, a direction of 0 is a vertical icon and increments by 22.5° (360/16).

Types are based off of rows and columns in map_icons.png:

Icon type	Result
0	White arrow (players)
1	Green arrow (item frames)
2	Red arrow
3	Blue arrow
4	White cross
5	Red pointer
6	White circle (off-map players)
7	Small white circle (far-off-map players)
8	Mansion
9	Monument
10	White Banner
11	Orange Banner
12	Magenta Banner
13	Light Blue Banner
14	Yellow Banner
15	Lime Banner
16	Pink Banner
17	Gray Banner
18	Light Gray Banner
19	Cyan Banner
20	Purple Banner
21	Blue Banner
22	Brown Banner
23	Green Banner
24	Red Banner
25	Black Banner
26	Treasure marker
27	Desert Village
28	Plains Village
29	Savanna Village
30	Snowy Village
31	Taiga Village
32	Jungle Temple
33	Swamp Hut
34	Trial Chambers

Merchant Offers

The list of trades a villager NPC is offering.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x2E resource: merchant_offers	Play	Client	Window ID		VarInt		The ID of the window that is open; this is an int rather than a byte.
			Trades	Input item 1	Prefixed Array	Trade Item	See below. The first item the player has to supply for this villager trade. The count of the item stack is the default "price" of this trade.
				Output item		Slot	The item the player will receive from this villager trade.
				Input item 2		Prefixed Optional Trade Item	The second item the player has to supply for this villager trade.
				Trade disabled		Boolean	True if the trade is disabled; false if the trade is enabled.
				Number of trade uses		Int	Number of times the trade has been used so far. If equal to the maximum number of trades, the client will display a red X.
				Maximum number of trade uses		Int	Number of times this trade can be used before it's exhausted.
				XP		Int	Amount of XP the villager will earn each time the trade is used.
				Special Price		Int	Can be zero or negative. The number is added to the price when an item is discounted due to player reputation or other effects.
				Price Multiplier		Float	Can be low (0.05) or high (0.2). Determines how much demand, player reputation, and temporary effects will adjust the price.
				Demand		Int	If positive, causes the price to increase. Negative values seem to be treated the same as zero.
			Villager level		VarInt		Appears on the trade GUI; meaning comes from the translation key merchant.level. + level. 1: Novice, 2: Apprentice, 3: Journeyman, 4: Expert, 5: Master.
			Experience		VarInt		Total experience for this villager (always 0 for the wandering trader).
			Is regular villager		Boolean		True if this is a regular villager; false for the wandering trader. When false, hides the villager level and some other GUI elements.
			Can restock		Boolean		True for regular villagers and false for the wandering trader. If true, the "Villagers restock up to two times per day." message is displayed when hovering over disabled trades.

Trade Item:

Field Name		Field Type		Meaning
Item ID		VarInt		The item ID. Item IDs are distinct from block IDs; see Data Generators for more information.
Item Count		VarInt		The item count.
Components	Component type	Prefixed Array	VarInt Enum	The type of component. See Structured components for more detail.
	Component data		Varies	The component-dependent data. See Structured components for more detail.

Modifiers can increase or decrease the number of items for the first input slot. The second input slot and the output slot never change the number of items. The number of items may never be less than 1, and never more than the stack size. If special price and demand are both zero, only the default price is displayed. If either is non-zero, then the adjusted price is displayed next to the crossed-out default price. The adjusted prices is calculated as follows:

Adjusted price = default price + floor(default price x multiplier x demand) + special price

The merchant UI, for reference

Update Entity Position

This packet is sent by the server when an entity moves a small distance. The change in position is represented as a fixed-point number with 12 fraction bits and 4 integer bits. As such, the maximum movement distance along each axis is 8 blocks in the negative direction, or 7.999755859375 blocks in the positive direction. If the movement exceeds these limits, Teleport Entity should be sent instead.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2F resource: move_entity_pos	Play	Client	Entity ID	VarInt
			Delta X	Short	Change in X position as currentX * 4096 - prevX * 4096.
			Delta Y	Short	Change in Y position as currentY * 4096 - prevY * 4096.
			Delta Z	Short	Change in Z position as currentZ * 4096 - prevZ * 4096.
			On Ground	Boolean

Update Entity Position and Rotation

This packet is sent by the server when an entity rotates and moves. See #Update Entity Position for how the position is encoded.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x30 resource: move_entity_pos_rot	Play	Client	Entity ID	VarInt
			Delta X	Short	Change in X position as currentX * 4096 - prevX * 4096.
			Delta Y	Short	Change in Y position as currentY * 4096 - prevY * 4096.
			Delta Z	Short	Change in Z position as currentZ * 4096 - prevZ * 4096.
			Yaw	Angle	New angle, not a delta.
			Pitch	Angle	New angle, not a delta.
			On Ground	Boolean

Move Minecart Along Track

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x31 resource: move_minecart_along_track	Play	Client	Entity ID		VarInt
			Steps	X	Prefixed Array	Double
				Y		Double
				Z		Double
				Velocity X		Double
				Velocity Y		Double
				Velocity Z		Double
				Yaw		Angle
				Pitch		Angle
				Weight		Float

Update Entity Rotation

This packet is sent by the server when an entity rotates.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x32 resource: move_entity_rot	Play	Client	Entity ID	VarInt
			Yaw	Angle	New angle, not a delta.
			Pitch	Angle	New angle, not a delta.
			On Ground	Boolean

Move Vehicle

Note that all fields use absolute positioning and do not allow for relative positioning.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x33 resource: move_vehicle	Play	Client	X	Double	Absolute position (X coordinate).
			Y	Double	Absolute position (Y coordinate).
			Z	Double	Absolute position (Z coordinate).
			Yaw	Float	Absolute rotation on the vertical axis, in degrees.
			Pitch	Float	Absolute rotation on the horizontal axis, in degrees.

Open Book

Sent when a player right clicks with a signed book. This tells the client to open the book GUI.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x34 resource: open_book	Play	Client	Hand	VarInt Enum	0: Main hand, 1: Off hand .

Open Screen

This is sent to the client when it should open an inventory, such as a chest, workbench, furnace, or other container. Resending this packet with already existing window id, will update the window title and window type without closing the window.

This message is not sent to clients opening their own inventory, nor do clients inform the server in any way when doing so. From the server's perspective, the inventory is always "open" whenever no other windows are.

For horses, use Open Horse Screen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x35 resource: open_screen	Play	Client	Window ID	VarInt	An identifier for the window to be displayed. vanilla server implementation is a counter, starting at 1. There can only be one window at a time; this is only used to ignore outdated packets targeting already-closed windows. Note also that the Window ID field in most other packets is only a single byte, and indeed, the vanilla server wraps around after 100.
			Window Type	VarInt	The window type to use for display. Contained in the minecraft:menu registry; see Inventory for the different values.
			Window Title	Text Component	The title of the window.

Open Sign Editor

Sent when the client has placed a sign and is allowed to send Update Sign. There must already be a sign at the given location (which the client does not do automatically) - send a Block Update first.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x36 resource: open_sign_editor	Play	Client	Location	Position
			Is Front Text	Boolean	Whether the opened editor is for the front or on the back of the sign

Ping (play)

Packet is not used by the vanilla server. When sent to the client, client responds with a Pong packet with the same id.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x37 resource: ping	Play	Client	ID	Int

Ping Response (play)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x38 resource: pong_response	Play	Client	Payload	Long	Should be the same as sent by the client.

Place Ghost Recipe

Response to the serverbound packet (Place Recipe), with the same recipe ID. Appears to be used to notify the UI.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x39 resource: place_ghost_recipe	Play	Client	Window ID	VarInt
			Recipe Display	Recipe Display

Player Abilities (clientbound)

The latter 2 floats are used to indicate the flying speed and field of view respectively, while the first byte is used to determine the value of 4 booleans.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3A resource: player_abilities	Play	Client	Flags	Byte	Bit field, see below.
			Flying Speed	Float	0.05 by default.
			Field of View Modifier	Float	Modifies the field of view, like a speed potion. A vanilla server will use the same value as the movement speed sent in the Update Attributes packet, which defaults to 0.1 for players.

About the flags:

Field	Bit
Invulnerable	0x01
Flying	0x02
Allow Flying	0x04
Creative Mode (Instant Break)	0x08

If Flying is set but Allow Flying is unset, the player is unable to stop flying.

Player Chat Message

Sends the client a chat message from a player.

Currently a lot is unknown about this packet, blank descriptions are for those that are unknown

Packet ID	State	Bound To	Sector	Field Name		Field Type	Notes
protocol: 0x3B resource: player_chat	Play	Client	Header	Sender		UUID	Used by the vanilla client for the disableChat launch option. Setting both longs to 0 will always display the message regardless of the setting.
				Index		VarInt
				Message Signature bytes		Prefixed Optional Byte Array (256)	Cryptography, the signature consists of the Sender UUID, Session UUID from the Player Session packet, Index, Salt, Timestamp in epoch seconds, the length of the original chat content, the original content itself, the length of Previous Messages, and all of the Previous message signatures. These values are hashed with SHA-256 and signed using the RSA cryptosystem. Modifying any of these values in the packet will cause this signature to fail. This buffer is always 256 bytes long and it is not length-prefixed.
			Body	Message		String (256)	Raw (optionally) signed sent message content. This is used as the content parameter when formatting the message on the client.
				Timestamp		Long	Represents the time the message was signed as milliseconds since the epoch, used to check if the message was received within 2 minutes of it being sent.
				Salt		Long	Cryptography, used for validating the message signature.
			Prefixed Array (20)	Message ID	VarInt	The message Id + 1, used for validating message signature. The next field is present only when value of this field is equal to 0.
				Signature	Optional Byte Array (256)	The previous message's signature. Contains the same type of data as Message Signature bytes (256 bytes) above. Not length-prefxied.
			Other	Unsigned Content		Prefixed Optional Text Component
				Filter Type		VarInt Enum	If the message has been filtered
				Filter Type Bits		Optional BitSet	Only present if the Filter Type is Partially Filtered. Specifies the indexes at which characters in the original message string should be replaced with the # symbol (i.e. filtered) by the vanilla client
			Chat Formatting	Chat Type		VarInt	The type of chat in the minecraft:chat_type registry, defined by the Registry Data packet. This should not be 0, meaning it is likely index+1
				Sender Name		Text Component	The name of the one sending the message, usually the sender's display name. This is used as the sender parameter when formatting the message on the client.
				Target Name		Prefixed Optional Text Component	The name of the one receiving the message, usually the receiver's display name. This is used as the target parameter when formatting the message on the client.

Player Chat Handling Logic

Filter Types:

The filter type mask should NOT be specified unless partially filtered is selected

ID	Name	Description
0	PASS_THROUGH	Message is not filtered at all
1	FULLY_FILTERED	Message is fully filtered
2	PARTIALLY_FILTERED	Only some characters in the message are filtered

End Combat

Unused by the vanilla client. This data was once used for twitch.tv metadata circa 1.8.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3C resource: player_combat_end	Play	Client	Duration	VarInt	Length of the combat in ticks.

Enter Combat

Unused by the vanilla client. This data was once used for twitch.tv metadata circa 1.8.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3D resource: player_combat_enter	Play	Client	no fields

Combat Death

Used to send a respawn screen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3E resource: player_combat_kill	Play	Client	Player ID	VarInt	Entity ID of the player that died (should match the client's entity ID).
			Message	Text Component	The death message.

Player Info Remove

Used by the server to remove players from the player list.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3F resource: player_info_remove	Play	Client	UUIDs	Prefixed Array of UUID	UUIDs of players to remove.

Player Info Update

Sent by the server to update the user list (<tab> in the client).

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x40 resource: player_info_update	Play	Client	Actions		EnumSet		Determines what actions are present.
			Players	UUID	Prefixed Array	UUID	The player UUID
				Player Actions		Array of Player Actions	The length of this array is determined by the number of Player Actions that give a non-zero value when applying its mask to the actions flag. For example given the decimal number 5, binary 00000101. The masks 0x01 and 0x04 would return a non-zero value, meaning the Player Actions array would include two actions: Add Player and Update Game Mode.

Player Actions

Action	Mask	Field Name		Type		Notes
Add Player	0x01	Name		String (16)
		Property	Name	Prefixed Array (16)	String (64)
			Value		String (32767)
			Signature		Prefixed Optional String (1024)
Initialize Chat	0x02	Data	Chat session ID	Prefixed Optional	UUID
			Public key expiry time		Long	Key expiry time, as a UNIX timestamp in milliseconds. Only sent if Has Signature Data is true.
			Encoded public key		Prefixed Array (512) of Byte	The player's public key, in bytes. Only sent if Has Signature Data is true.
			Public key signature		Prefixed Array (4096) of Byte	The public key's digital signature. Only sent if Has Signature Data is true.
Update Game Mode	0x04	Game Mode		VarInt
Update Listed	0x08	Listed		Boolean		Whether the player should be listed on the player list.
Update Latency	0x10	Ping		VarInt		Measured in milliseconds.
Update Display Name	0x20	Display Name		Prefixed Optional Text Component		Only sent if Has Display Name is true.
Update List Priority	0x40	Priority		VarInt		See below.
Update Hat	0x80	Visible		Boolean		Whether the player's hat skin layer is shown.

The properties included in this packet are the same as in Login Success, for the current player.

Ping values correspond with icons in the following way:

• A ping that negative (i.e. not known to the server yet) will result in the no connection icon.
• A ping under 150 milliseconds will result in 5 bars
• A ping under 300 milliseconds will result in 4 bars
• A ping under 600 milliseconds will result in 3 bars
• A ping under 1000 milliseconds (1 second) will result in 2 bars
• A ping greater than or equal to 1 second will result in 1 bar.

The order of players in the player list is determined as follows:

• Players with higher priorities are sorted before those with lower priorities.
• Among players of equal priorities, spectators are sorted after non-spectators.
• Within each of those groups, players are sorted into teams. The teams are ordered case-sensitively by team name in ascending order. Players with no team are listed first.
• The players of each team (and non-team) are sorted case-insensitively by name in ascending order.

Look At

Used to rotate the client player to face the given location or entity (for /teleport [<targets>] <x> <y> <z> facing).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x41 resource: player_look_at	Play	Client
			Feet/eyes	VarInt Enum	Values are feet=0, eyes=1. If set to eyes, aims using the head position; otherwise aims using the feet position.
			Target x	Double	x coordinate of the point to face towards.
			Target y	Double	y coordinate of the point to face towards.
			Target z	Double	z coordinate of the point to face towards.
			Is entity	Boolean	If true, additional information about an entity is provided.
			Entity ID	Optional VarInt	Only if is entity is true — the entity to face towards.
			Entity feet/eyes	Optional VarInt Enum	Whether to look at the entity's eyes or feet. Same values and meanings as before, just for the entity's head/feet.

If the entity given by entity ID cannot be found, this packet should be treated as if is entity was false.

Synchronize Player Position

Teleports the client, e.g. during login, when using an ender pearl, in response to invalid move packets, etc.

Due to latency, the server may receive outdated movement packets sent before the client was aware of the teleport. To account for this, the server ignores all movement packets from the client until a Confirm Teleportation packet with an ID matching the one sent in the teleport packet is received.

Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the XZ-plane starts at (0, 1) and turns counterclockwise, with 90 at (-1, 0), 180 at (0, -1) and 270 at (1, 0). Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360 (see MC-90097).

Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x42 resource: player_position	Play	Client	Teleport ID	VarInt	Client should confirm this packet with Confirm Teleportation containing the same Teleport ID.
			X	Double	Absolute or relative position, depending on Flags.
			Y	Double	Absolute or relative position, depending on Flags.
			Z	Double	Absolute or relative position, depending on Flags.
			Velocity X	Double
			Velocity Y	Double
			Velocity Z	Double
			Yaw	Float	Absolute or relative rotation on the X axis, in degrees.
			Pitch	Float	Absolute or relative rotation on the Y axis, in degrees.
			Flags	Teleport Flags

Player Rotation

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x43 resource: player_rotation	Play	Client	Yaw	Float	Rotation on the X axis, in degrees.
			Pitch	Float	Rotation on the Y axis, in degrees.

Recipe Book Add

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x44 resource: recipe_book_add	Play	Client	Recipes	Recipe ID	Prefixed Array	VarInt	ID to assign to the recipe.
				Display		Recipe Display
				Group ID		VarInt
				Category ID		VarInt	ID in the minecraft:recipe_book_category registry.
				Ingredients		Prefixed Optional Prefixed Array of ID Set	IDs in the minecraft:item registry, or an inline definition.
				Flags		Byte	0x01: show notification; 0x02: highlight as new
			Replace		Boolean		Replace or Add to known recipes

Recipe Book Remove

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x45 resource: recipe_book_remove	Play	Client	Recipes	Prefixed Array of VarInt	IDs of recipes to remove.

Recipe Book Settings

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x46 resource: recipe_book_settings	Play	Client	Crafting Recipe Book Open	Boolean	If true, then the crafting recipe book will be open when the player opens its inventory.
			Crafting Recipe Book Filter Active	Boolean	If true, then the filtering option is active when the players opens its inventory.
			Smelting Recipe Book Open	Boolean	If true, then the smelting recipe book will be open when the player opens its inventory.
			Smelting Recipe Book Filter Active	Boolean	If true, then the filtering option is active when the players opens its inventory.
			Blast Furnace Recipe Book Open	Boolean	If true, then the blast furnace recipe book will be open when the player opens its inventory.
			Blast Furnace Recipe Book Filter Active	Boolean	If true, then the filtering option is active when the players opens its inventory.
			Smoker Recipe Book Open	Boolean	If true, then the smoker recipe book will be open when the player opens its inventory.
			Smoker Recipe Book Filter Active	Boolean	If true, then the filtering option is active when the players opens its inventory.

Remove Entities

Sent by the server when an entity is to be destroyed on the client.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x47 resource: remove_entities	Play	Client	Entity IDs	Prefixed Array of VarInt	The list of entities to destroy.

Remove Entity Effect

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x48 resource: remove_mob_effect	Play	Client	Entity ID	VarInt
			Effect ID	VarInt	See this table.

Reset Score

This is sent to the client when it should remove a scoreboard item.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x49 resource: reset_score	Play	Client	Entity Name	String (32767)	The entity whose score this is. For players, this is their username; for other entities, it is their UUID.
			Objective Name	Prefixed Optional String (32767)	The name of the objective the score belongs to.

Remove Resource Pack (play)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4A resource: resource_pack_pop	Play	Client	UUID	Optional UUID	The UUID of the resource pack to be removed.

Add Resource Pack (play)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4B resource: resource_pack_push	Play	Client	UUID	UUID	The unique identifier of the resource pack.
			URL	String (32767)	The URL to the resource pack.
			Hash	String (40)	A 40 character hexadecimal, case-insensitive SHA-1 hash of the resource pack file. If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth.
			Forced	Boolean	The vanilla client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
			Prompt Message	Prefixed Optional Text Component	This is shown in the prompt making the client accept or decline the resource pack.

Respawn

To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4C resource: respawn	Play	Client	Dimension Type	VarInt	The ID of type of dimension in the minecraft:dimension_type registry, defined by the Registry Data packet.
			Dimension Name	Identifier	Name of the dimension being spawned into.
			Hashed seed	Long	First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
			Game mode	Unsigned Byte	0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
			Previous Game mode	Byte	-1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous game mode. Vanilla client uses this for the debug (F3 + N & F3 + F4) game mode switch. (More information needed)
			Is Debug	Boolean	True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
			Is Flat	Boolean	True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
			Has death location	Boolean	If true, then the next two fields are present.
			Death dimension Name	Optional Identifier	Name of the dimension the player died in.
			Death location	Optional Position	The location that the player died at.
			Portal cooldown	VarInt	The number of ticks until the player can use the portal again.
			Sea level	VarInt
			Data kept	Byte	Bit mask. 0x01: Keep attributes, 0x02: Keep metadata. Tells which data should be kept on the client side once the player has respawned. In the vanilla implementation, this is context dependent: normal respawns (after death) keep no data; exiting the end poem/credits keeps the attributes; other dimension changes (portals or teleports) keep all data.

Set Head Rotation

Changes the direction an entity's head is facing.

While sending the Entity Look packet changes the vertical rotation of the head, sending this packet appears to be necessary to rotate the head horizontally.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4D resource: rotate_head	Play	Client	Entity ID	VarInt
			Head Yaw	Angle	New angle, not a delta.

Update Section Blocks

Fired whenever 2 or more blocks are changed within the same chunk on the same tick.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4E resource: section_blocks_update	Play	Client	Chunk section position	Long	Chunk section coordinate (encoded chunk x and z with each 22 bits, and section y with 20 bits, from left to right).
			Blocks	Prefixed Array of VarLong	Each entry is composed of the block state id, shifted left by 12, and the relative block position in the chunk section (4 bits for x, z, and y, from left to right).

Chunk section position is encoded:

((sectionX & 0x3FFFFF) << 42) | (sectionY & 0xFFFFF) | ((sectionZ & 0x3FFFFF) << 20);

and decoded:

sectionX = long >> 42;
sectionY = long << 44 >> 44;
sectionZ = long << 22 >> 42;

Blocks are encoded:

blockStateId << 12 | (blockLocalX << 8 | blockLocalZ << 4 | blockLocalY)
//Uses the local position of the given block position relative to its respective chunk section

and decoded:

blockStateId = long >> 12;
blockLocalX = (long >> 8) & 0xF;
blockLocalY = long & 0xF;
blockLocalZ = (long >> 4) & 0xF;

Select Advancements Tab

Sent by the server to indicate that the client should switch advancement tab. Sent either when the client switches tab in the GUI or when an advancement in another tab is made.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x4F resource: select_advancements_tab	Play	Client	Identifier	Prefixed Optional Identifier	See below.

The Identifier must be one of the following if no custom data pack is loaded:

Identifier
minecraft:story/root
minecraft:nether/root
minecraft:end/root
minecraft:adventure/root
minecraft:husbandry/root

If no or an invalid identifier is sent, the client will switch to the first tab in the GUI.

Server Data

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x50 resource: server_data	Play	Client	MOTD	Text Component
			Icon	Prefixed Optional Prefixed Array of Byte	Icon bytes in the PNG format.

Set Action Bar Text

Displays a message above the hotbar. Equivalent to System Chat Message with Overlay set to true, except that chat message blocking isn't performed. Used by the vanilla server only to implement the /title command.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x51 resource: set_action_bar_text	Play	Client	Action bar text	Text Component

Set Border Center

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x52 resource: set_border_center	Play	Client	X	Double
			Z	Double

Set Border Lerp Size

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x53 resource: set_border_lerp_size	Play	Client	Old Diameter	Double	Current length of a single side of the world border, in meters.
			New Diameter	Double	Target length of a single side of the world border, in meters.
			Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that vanilla server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.

Set Border Size

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x54 resource: set_border_size	Play	Client	Diameter	Double	Length of a single side of the world border, in meters.

Set Border Warning Delay

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x55 resource: set_border_warning_delay	Play	Client	Warning Time	VarInt	In seconds as set by /worldborder warning time.

Set Border Warning Distance

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x56 resource: set_border_warning_distance	Play	Client	Warning Blocks	VarInt	In meters.

Set Camera

Sets the entity that the player renders from. This is normally used when the player left-clicks an entity while in spectator mode.

The player's camera will move with the entity and look where it is looking. The entity is often another player, but can be any type of entity. The player is unable to move this entity (move packets will act as if they are coming from the other entity).

If the given entity is not loaded by the player, this packet is ignored. To return control to the player, send this packet with their entity ID.

The vanilla server resets this (sends it back to the default entity) whenever the spectated entity is killed or the player sneaks, but only if they were spectating an entity. It also sends this packet whenever the player switches out of spectator mode (even if they weren't spectating an entity).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x57 resource: set_camera	Play	Client	Camera ID	VarInt	ID of the entity to set the client's camera to.

The vanilla client also loads certain shaders for given entities:

• Creeper → shaders/post/creeper.json
• Spider (and cave spider) → shaders/post/spider.json
• Enderman → shaders/post/invert.json
• Anything else → the current shader is unloaded

Set Center Chunk

Sets the center position of the client's chunk loading area. The area is square-shaped, spanning 2 × server view distance + 7 chunks on both axes (width, not radius!). Since the area's width is always an odd number, there is no ambiguity as to which chunk is the center.

The vanilla client ignores attempts to send chunks located outside the loading area, and immediately unloads any existing chunks no longer inside it.

The center chunk is normally the chunk the player is in, but apart from the implications on chunk loading, the (vanilla) client takes no issue with this not being the case. Indeed, as long as chunks are sent only within the default loading area centered on the world origin, it is not necessary to send this packet at all. This may be useful for servers with small bounded worlds, such as minigames, since it ensures chunks never need to be resent after the client has joined, saving on bandwidth.

The vanilla server sends this packet whenever the player moves across a chunk border horizontally, and also (according to testing) for any integer change in the vertical axis, even if it doesn't go across a chunk section border.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x58 resource: set_chunk_cache_center	Play	Client	Chunk X	VarInt	Chunk X coordinate of the loading area center.
			Chunk Z	VarInt	Chunk Z coordinate of the loading area center.

Set Render Distance

Sent by the integrated singleplayer server when changing render distance. This packet is sent by the server when the client reappears in the overworld after leaving the end.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x59 resource: set_chunk_cache_radius	Play	Client	View Distance	VarInt	Render distance (2-32).

Set Cursor Item

Replaces or sets the inventory item that's being dragged with the mouse.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5A resource: set_cursor_item	Play	Client	Carried item	Slot

Set Default Spawn Position

Sent by the server after login to specify the coordinates of the spawn point (the point at which players spawn at, and which the compass points to). It can be sent at any time to update the point compasses point at.

The client uses this as the default position of the player upon spawning, though it's a good idea to always override this default by sending Synchronize Player Position. When converting the position to floating point, 0.5 is added to the x and z coordinates and 1.0 to the y coordinate, so as to place the player centered on top of the specified block position.

Before receiving this packet, the client uses the default position 8, 64, 8, and angle 0.0 (resulting in a default player spawn position of 8.5, 65.0, 8.5).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5B resource: set_default_spawn_position	Play	Client	Location	Position	Spawn location.
			Angle	Float	The angle at which to respawn at.

Display Objective

This is sent to the client when it should display a scoreboard.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5C resource: set_display_objective	Play	Client	Position	VarInt	The position of the scoreboard. 0: list, 1: sidebar, 2: below name, 3 - 18: team specific sidebar, indexed as 3 + team color.
			Score Name	String (32767)	The unique name for the scoreboard to be displayed.

Set Entity Metadata

Updates one or more metadata properties for an existing entity. Any properties not included in the Metadata field are left unchanged.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5D resource: set_entity_data	Play	Client	Entity ID	VarInt
			Metadata	Entity Metadata

Link Entities

This packet is sent when an entity has been leashed to another entity.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5E resource: set_entity_link	Play	Client	Attached Entity ID	Int	Attached entity's EID.
			Holding Entity ID	Int	ID of the entity holding the lead. Set to -1 to detach.

Set Entity Velocity

Velocity is in units of 1/8000 of a block per server tick (50ms); for example, -1343 would move (-1343 / 8000) = −0.167875 blocks per tick (or −3.3575 blocks per second).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x5F resource: set_entity_motion	Play	Client	Entity ID	VarInt
			Velocity X	Short	Velocity on the X axis.
			Velocity Y	Short	Velocity on the Y axis.
			Velocity Z	Short	Velocity on the Z axis.

Set Equipment

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x60 resource: set_equipment	Play	Client	Entity ID		VarInt		Entity's ID.
			Equipment	Slot	Array	Byte Enum	The length of the array is unknown, it must be read until the most significant bit is 1 ((Slot >>> 7 & 1) == 1)	Equipment slot (see below). Also has the top bit set if another entry follows, and otherwise unset if this is the last item in the array.
				Item		Slot

Equipment slot can be one of the following:

ID	Equipment slot
0	Main hand
1	Off hand
2	Boots
3	Leggings
4	Chestplate
5	Helmet
6	Body

Set Experience

Sent by the server when the client should change experience levels.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x61 resource: set_experience	Play	Client	Experience bar	Float	Between 0 and 1.
			Level	VarInt
			Total Experience	VarInt	See Experience#Leveling up on the Minecraft Wiki for Total Experience to Level conversion.

Set Health

Sent by the server to set the health of the player it is sent to.

Food saturation acts as a food “overcharge”. Food values will not decrease while the saturation is over zero. New players logging in or respawning automatically get a saturation of 5.0. Eating food increases the saturation as well as the food bar.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x62 resource: set_health	Play	Client	Health	Float	0 or less = dead, 20 = full HP.
			Food	VarInt	0–20.
			Food Saturation	Float	Seems to vary from 0.0 to 5.0 in integer increments.

Set Held Item (clientbound)

Sent to change the player's slot selection.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x63 resource: set_held_slot	Play	Client	Slot	VarInt	The slot which the player has selected (0–8).

Update Objectives

This is sent to the client when it should create a new scoreboard objective or remove one.

Packet ID	State	Bound To	Field Name		Field Type	Notes
protocol: 0x64 resource: set_objective	Play	Client	Objective Name		String (32767)	A unique name for the objective.
			Mode		Byte	0 to create the scoreboard. 1 to remove the scoreboard. 2 to update the display text.
			Objective Value		Optional Text Component	Only if mode is 0 or 2.The text to be displayed for the score.
			Type		Optional VarInt Enum	Only if mode is 0 or 2. 0 = "integer", 1 = "hearts".
			Has Number Format		Optional Boolean	Only if mode is 0 or 2. Whether this objective has a set number format for the scores.
			Number Format		Optional VarInt Enum	Only if mode is 0 or 2 and the previous boolean is true. Determines how the score number should be formatted.
			Number Format	Field Name
			0: blank	no fields		Show nothing.
			1: styled	Styling	Compound Tag	The styling to be used when formatting the score number. Contains the text component styling fields.
			2: fixed	Content	Text Component	The text to be used as placeholder.

Set Passengers

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x65 resource: set_passengers	Play	Client	Entity ID	VarInt	Vehicle's EID.
			Passengers	Prefixed Array of VarInt	EIDs of entity's passengers.

Set Player Inventory Slot

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x66 resource: set_player_inventory	Play	Client	Slot	VarInt
			Slot Data	Slot

Update Teams

Creates and updates teams.

Packet ID	State	Bound To	Field Name		Field Type	Notes
protocol: 0x67 resource: set_player_team	Play	Client	Team Name		String (32767)	A unique name for the team. (Shared with scoreboard).
			Method		Byte	Determines the layout of the remaining packet.
			0: create team	Team Display Name	Text Component
				Friendly Flags	Byte	Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible players on same team.
				Name Tag Visibility	String Enum (40)	always, hideForOtherTeams, hideForOwnTeam, never.
				Collision Rule	String Enum (40)	always, pushOtherTeams, pushOwnTeam, never.
				Team Color	VarInt Enum	Used to color the name of players on the team; see below.
				Team Prefix	Text Component	Displayed before the names of players that are part of this team.
				Team Suffix	Text Component	Displayed after the names of players that are part of this team.
				Entities	Prefixed Array of String (32767)	Identifiers for the entities in this team. For players, this is their username; for other entities, it is their UUID.
			1: remove team	no fields	no fields
			2: update team info	Team Display Name	Text Component
				Friendly Flags	Byte	Bit mask. 0x01: Allow friendly fire, 0x02: can see invisible entities on same team.
				Name Tag Visibility	String Enum (40)	always, hideForOtherTeams, hideForOwnTeam, never
				Collision Rule	String Enum (40)	always, pushOtherTeams, pushOwnTeam, never
				Team Color	VarInt Enum	Used to color the name of players on the team; see below.
				Team Prefix	Text Component	Displayed before the names of players that are part of this team.
				Team Suffix	Text Component	Displayed after the names of players that are part of this team.
			3: add entities to team	Entities	Prefixed Array of String (32767)	Identifiers for the added entities. For players, this is their username; for other entities, it is their UUID.
			4: remove entities from team	Entities	Prefixed Array of String (32767)	Identifiers for the removed entities. For players, this is their username; for other entities, it is their UUID.

Team Color: The color of a team defines how the names of the team members are visualized; any formatting code can be used. The following table lists all the possible values.

ID	Formatting
0-15	Color formatting, same values as in Text formatting#Colors.
16	Obfuscated
17	Bold
18	Strikethrough
19	Underlined
20	Italic
21	Reset

Update Score

This is sent to the client when it should update a scoreboard item.

Packet ID	State	Bound To	Field Name		Field Type	Notes
protocol: 0x68 resource: set_score	Play	Client	Entity Name		String (32767)	The entity whose score this is. For players, this is their username; for other entities, it is their UUID.
			Objective Name		String (32767)	The name of the objective the score belongs to.
			Value		VarInt	The score to be displayed next to the entry.
			Display Name		Prefixed Optional Text Component	The custom display name.
			Number Format		Prefixed Optional VarInt Enum	Determines how the score number should be formatted.
			Number Format	Field Name
			0: blank	no fields		Show nothing.
			1: styled	Styling	Compound Tag	The styling to be used when formatting the score number. Contains the text component styling fields.
			2: fixed	Content	Text Component	The text to be used as placeholder.

Set Simulation Distance

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x69 resource: set_simulation_distance	Play	Client	Simulation Distance	VarInt	The distance that the client will process specific things, such as entities.

Set Subtitle Text

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6A resource: set_subtitle_text	Play	Client	Subtitle Text	Text Component

Update Time

Time is based on ticks, where 20 ticks happen every second. There are 24000 ticks in a day, making Minecraft days exactly 20 minutes long.

The time of day is based on the timestamp modulo 24000. 0 is sunrise, 6000 is noon, 12000 is sunset, and 18000 is midnight.

The default SMP server increments the time by 20 every second.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6B resource: set_time	Play	Client	World Age	Long	In ticks; not changed by server commands.
			Time of day	Long	The world (or region) time, in ticks.
			Time of day increasing	Boolean	If true, the client should automatically advance the time of day according to its ticking rate.

Set Title Text

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6C resource: set_title_text	Play	Client	Title Text	Text Component

Set Title Animation Times

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6D resource: set_titles_animation	Play	Client	Fade In	Int	Ticks to spend fading in.
			Stay	Int	Ticks to keep the title displayed.
			Fade Out	Int	Ticks to spend fading out, not when to start fading out.

Entity Sound Effect

Plays a sound effect from an entity, either by hardcoded ID or Identifier. Sound IDs and names can be found here.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6E resource: sound_entity	Play	Client	Sound Event	ID or Sound Event	ID in the minecraft:sound_event registry, or an inline definition.
			Sound Category	VarInt Enum	The category that this sound will be played from (current categories).
			Entity ID	VarInt
			Volume	Float	1.0 is 100%, capped between 0.0 and 1.0 by vanilla clients.
			Pitch	Float	Float between 0.5 and 2.0 by vanilla clients.
			Seed	Long	Seed used to pick sound variant.

Sound Effect

Plays a sound effect at the given location, either by hardcoded ID or Identifier. Sound IDs and names can be found here.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x6F resource: sound	Play	Client	Sound Event	ID or Sound Event	ID in the minecraft:sound_event registry, or an inline definition.
			Sound Category	VarInt Enum	The category that this sound will be played from (current categories).
			Effect Position X	Int	Effect X multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
			Effect Position Y	Int	Effect Y multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
			Effect Position Z	Int	Effect Z multiplied by 8 (fixed-point number with only 3 bits dedicated to the fractional part).
			Volume	Float	1.0 is 100%, capped between 0.0 and 1.0 by vanilla clients.
			Pitch	Float	Float between 0.5 and 2.0 by vanilla clients.
			Seed	Long	Seed used to pick sound variant.

Start Configuration

Sent during gameplay in order to redo the configuration process. The client must respond with Acknowledge Configuration for the process to start.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x70 resource: start_configuration	Play	Client	no fields

This packet switches the connection state to configuration.

Stop Sound

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x71 resource: stop_sound	Play	Client	Flags	Byte	Controls which fields are present.
			Source	Optional VarInt Enum	Only if flags is 3 or 1 (bit mask 0x1). See below. If not present, then sounds from all sources are cleared.
			Sound	Optional Identifier	Only if flags is 2 or 3 (bit mask 0x2). A sound effect name, see Custom Sound Effect. If not present, then all sounds are cleared.

Categories:

Name	Value
master	0
music	1
record	2
weather	3
block	4
hostile	5
neutral	6
player	7
ambient	8
voice	9

Store Cookie (play)

Stores some arbitrary data on the client, which persists between server transfers. The vanilla client only accepts cookies of up to 5 kiB in size.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x72 resource: store_cookie	Play	Client	Key	Identifier	The identifier of the cookie.
			Payload	Prefixed Array (5120) of Byte	The data of the cookie.

System Chat Message

Sends the client a raw system message.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x73 resource: system_chat	Play	Client	Content	Text Component	Limited to 262144 bytes.
			Overlay	Boolean	Whether the message is an actionbar or chat message. See also #Set Action Bar Text.

Set Tab List Header And Footer

This packet may be used by custom servers to display additional information above/below the player list. It is never sent by the vanilla server.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x74 resource: tab_list	Play	Client	Header	Text Component	To remove the header, send a empty text component: {"text":""}.
			Footer	Text Component	To remove the footer, send a empty text component: {"text":""}.

Tag Query Response

Sent in response to Query Block Entity Tag or Query Entity Tag.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x75 resource: tag_query	Play	Client	Transaction ID	VarInt	Can be compared to the one sent in the original query packet.
			NBT	NBT	The NBT of the block or entity. May be a TAG_END (0) in which case no NBT is present.

Pickup Item

Sent by the server when someone picks up an item lying on the ground — its sole purpose appears to be the animation of the item flying towards you. It doesn't destroy the entity in the client memory, and it doesn't add it to your inventory. The server only checks for items to be picked up after each Set Player Position (and Set Player Position And Rotation) packet sent by the client. The collector entity can be any entity; it does not have to be a player. The collected entity also can be any entity, but the vanilla server only uses this for items, experience orbs, and the different varieties of arrows.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x76 resource: take_item_entity	Play	Client	Collected Entity ID	VarInt
			Collector Entity ID	VarInt
			Pickup Item Count	VarInt	Seems to be 1 for XP orbs, otherwise the number of items in the stack.

Synchronize Vehicle Position

Teleports the entity on the client without changing the reference point of movement deltas in future Update Entity Position packets. Seems to be used to make relative adjustments to vehicle positions; more information needed.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x77 resource: teleport_entity	Play	Client	Entity ID	VarInt
			X	Double
			Y	Double
			Z	Double
			Velocity X	Double
			Velocity Y	Double
			Velocity Z	Double
			Yaw	Float	Rotation on the Y axis, in degrees.
			Pitch	Float	Rotation on the Y axis, in degrees.
			Flags	Teleport Flags
			On Ground	Boolean

Set Ticking State

Used to adjust the ticking rate of the client, and whether it's frozen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x78 resource: ticking_state	Play	Client	Tick rate	Float
			Is frozen	Boolean

Step Tick

Advances the client processing by the specified number of ticks. Has no effect unless client ticking is frozen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x79 resource: ticking_step	Play	Client	Tick steps	VarInt

Transfer (play)

Notifies the client that it should transfer to the given server. Cookies previously stored are preserved between server transfers.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x7A resource: transfer	Play	Client	Host		String		The hostname or IP of the server.
			Port		VarInt		The port of the server.

Update Advancements

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x7B resource: update_advancements	Play	Client	Reset/Clear		Boolean		Whether to reset/clear the current advancements.
			Advancement mapping	Key	Prefixed Array	Identifier	The identifier of the advancement.
				Value		Advancement	See below
			Identifiers		Prefixed Array of Identifier		The identifiers of the advancements that should be removed.
			Progress mapping	Key	Prefixed Array	Identifier	The identifier of the advancement.
				Value		Advancement progress	See below.

Advancement structure:

Field Name		Field Type		Notes
Parent id		Prefixed Optional Identifier		The identifier of the parent advancement.
Display data		Prefixed Optional Advancement display		See below.
Nested requirements		Prefixed Array	Prefixed Array of String (32767)	Array with a sub-array of criteria. To check if the requirements are met, each sub-array must be tested and mapped with the OR operator, resulting in a boolean array. These booleans must be mapped with the AND operator to get the result.
Sends telemetry data		Boolean		Whether the client should include this achievement in the telemetry data when it's completed. The vanilla client only sends data for advancements on the minecraft namespace.

Advancement display:

Field Name	Field Type	Notes
Title	Text Component
Description	Text Component
Icon	Slot
Frame type	VarInt Enum	0 = task, 1 = challenge, 2 = goal.
Flags	Int	0x01: has background texture; 0x02: show_toast; 0x04: hidden.
Background texture	Optional Identifier	Background texture location. Only if flags indicates it.
X coord	Float
Y coord	Float

Advancement progress:

Field Name		Field Type		Notes
Criteria	Criterion identifier	Prefixed Array	Identifier	The identifier of the criterion.
	Date of achieving		Prefixed Optional Long	Present if achieved. As returned by Date.getTime.

Update Attributes

Sets attributes on the given entity.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x7C resource: update_attributes	Play	Client	Entity ID		VarInt
			Property	Id	Prefixed Array	VarInt	ID in the minecraft:attribute registry. See also Attribute#Attributes.
				Value		Double	See below.
				Modifiers		Prefixed Array of Modifier Data	See Attribute#Modifiers. Modifier Data defined below.

Modifier Data structure:

Field Name	Field Type	Notes
Id	Identifier
Amount	Double	May be positive or negative.
Operation	Byte	See below.

The operation controls how the base value of the modifier is changed.

• 0: Add/subtract amount
• 1: Add/subtract amount percent of the current value
• 2: Multiply by amount percent

All of the 0's are applied first, and then the 1's, and then the 2's.

Entity Effect

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x7D resource: update_mob_effect	Play	Client	Entity ID	VarInt
			Effect ID	VarInt	See this table.
			Amplifier	VarInt	Vanilla client displays effect level as Amplifier + 1.
			Duration	VarInt	Duration in ticks. (-1 for infinite)
			Flags	Byte	Bit field, see below.

Within flags:

• 0x01: Is ambient - was the effect spawned from a beacon? All beacon-generated effects are ambient. Ambient effects use a different icon in the HUD (blue border rather than gray). If all effects on an entity are ambient, the "Is potion effect ambient" living metadata field should be set to true. Usually should not be enabled.
• 0x02: Show particles - should all particles from this effect be hidden? Effects with particles hidden are not included in the calculation of the effect color, and are not rendered on the HUD (but are still rendered within the inventory). Usually should be enabled.
• 0x04: Show icon - should the icon be displayed on the client? Usually should be enabled.
• 0x08: Blend - should the effect's hard-coded blending be applied? Currently only used in the DARKNESS effect to apply extra void fog and adjust the gamma value for lighting.

Update Recipes

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x7E resource: update_recipes	Play	Client	Property Sets	Property Set ID	Prefixed Array	Identifier
				Items		Prefixed Array of VarInt	IDs in the minecraft:item registry.
			Stonecutter Recipes	Ingredients	Prefixed Array	ID Set
				Slot Display		Slot Display

Update Tags (play)

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x7F resource: update_tags	Play	Client	Registry to tags map	Registry	Prefixed Array	Identifier	Registry identifier (Vanilla expects tags for the registries minecraft:block, minecraft:item, minecraft:fluid, minecraft:entity_type, and minecraft:game_event)
				Tags		Prefixed Array of Tag (See below)

A tag looks like this:

Field Name	Field Type	Notes
Tag name	Identifier
Entries	Prefixed Array of VarInt	Numeric IDs of the given type (block, item, etc.). This list replaces the previous list of IDs for the given tag. If some preexisting tags are left unmentioned, a warning is printed.

See Tag on the Minecraft Wiki for more information, including a list of vanilla tags.

Projectile Power

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x80 resource: projectile_power	Play	Client	Entity ID	VarInt
			Power	Double

Custom Report Details

Contains a list of key-value text entries that are included in any crash or disconnection report generated during connection to the server.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x81 resource: custom_report_details	Play	Client	Details	Title	Prefixed Array (32)	String (128)
				Description		String (4096)

Server Links

This packet contains a list of links that the vanilla client will display in the menu available from the pause menu. Link labels can be built-in or custom (i.e., any text).

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x82 resource: server_links	Play	Client	Links	Is built-in	Prefixed Array	Boolean	Determines if the following label is built-in (from enum) or custom (text component).
				Label		VarInt Enum / Text Component	See below.
				URL		String	Valid URL.

ID	Name	Notes
0	Bug Report	Displayed on connection error screen; included as a comment in the disconnection report.
1	Community Guidelines
2	Support
3	Status
4	Feedback
5	Community
6	Website
7	Forums
8	News
9	Announcements

Serverbound

Confirm Teleportation

Sent by client as confirmation of Synchronize Player Position.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x00 resource: accept_teleportation	Play	Server	Teleport ID	VarInt	The ID given by the Synchronize Player Position packet.

Query Block Entity Tag

Used when F3+I is pressed while looking at a block.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x01 resource: block_entity_tag_query	Play	Server	Transaction ID	VarInt	An incremental ID so that the client can verify that the response matches.
			Location	Position	The location of the block to check.

Bundle Item Selected

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x02 resource: bundle_item_selected	Play	Server	Slot of Bundle	VarInt
			Slot in Bundle	VarInt

Change Difficulty

Must have at least op level 2 to use. Appears to only be used on singleplayer; the difficulty buttons are still disabled in multiplayer.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x03 resource: change_difficulty	Play	Server	New difficulty	Unsigned Byte Enum	0: peaceful, 1: easy, 2: normal, 3: hard.

Acknowledge Message

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x04 resource: chat_ack	Play	Server	Message Count	VarInt

Chat Command

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x05 resource: chat_command	Play	Server	Command		String (32767)		The command typed by the client.

Signed Chat Command

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x06 resource: chat_command_signed	Play	Server	Command		String (32767)		The command typed by the client.
			Timestamp		Long		The timestamp that the command was executed.
			Salt		Long		The salt for the following argument signatures.
			Array of argument signatures	Argument name	Prefixed Array (8)	String (16)	The name of the argument that is signed by the following signature.
				Signature		Byte Array (256)	The signature that verifies the argument. Always 256 bytes and is not length-prefixed.
			Message Count		VarInt
			Acknowledged		Fixed BitSet (20)

Chat Message

Used to send a chat message to the server. The message may not be longer than 256 characters or else the server will kick the client.

The server will broadcast a Player Chat Message packet with Chat Type minecraft:chat to all players that haven't disabled chat (including the player that sent the message). See Chat#Processing chat for more information.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x07 resource: chat	Play	Server	Message	String (256)
			Timestamp	Long
			Salt	Long	The salt used to verify the signature hash.
			Signature	Prefixed Optional Byte Array (256)	The signature used to verify the chat message's authentication. When present, always 256 bytes and not length-prefixed.
			Message Count	VarInt
			Acknowledged	Fixed BitSet (20)

Player Session

Packet ID	State	Bound To	Field Name		Field Type	Notes
protocol: 0x08 resource: chat_session_update	Play	Server	Session Id		UUID
			Public Key	Expires At	Long	The time the play session key expires in epoch milliseconds.
				Public Key	Prefixed Array (512) of Byte	A byte array of an X.509-encoded public key.
				Key Signature	Prefixed Array (4096) of Byte	The signature consists of the player UUID, the key expiration timestamp, and the public key data. These values are hashed using SHA-1 and signed using Mojang's private RSA key.

Chunk Batch Received

Notifies the server that the chunk batch has been received by the client. The server uses the value sent in this packet to adjust the number of chunks to be sent in a batch.

The vanilla server will stop sending further chunk data until the client acknowledges the sent chunk batch. After the first acknowledgement, the server adjusts this number to allow up to 10 unacknowledged batches.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x09 resource: chunk_batch_received	Play	Server	Chunks per tick	Float	Desired chunks per tick.

Client Status

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0A resource: client_command	Play	Server	Action ID	VarInt Enum	See below

Action ID values:

Action ID	Action	Notes
0	Perform respawn	Sent when the client is ready to respawn after death.
1	Request stats	Sent when the client opens the Statistics menu.

Client Tick End

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0B resource: client_tick_end	Play	Server	no fields

Client Information (play)

Sent when the player connects, or when settings are changed.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0C resource: client_information	Play	Server	Locale	String (16)	e.g. en_GB.
			View Distance	Byte	Client-side render distance, in chunks.
			Chat Mode	VarInt Enum	0: enabled, 1: commands only, 2: hidden. See Chat#Client chat mode for more information.
			Chat Colors	Boolean	“Colors” multiplayer setting. The vanilla server stores this value but does nothing with it (see MC-64867). Third-party servers such as Hypixel disable all coloring in chat and system messages when it is false.
			Displayed Skin Parts	Unsigned Byte	Bit mask, see below.
			Main Hand	VarInt Enum	0: Left, 1: Right.
			Enable text filtering	Boolean	Enables filtering of text on signs and written book titles. The vanilla client sets this according to the profanityFilterPreferences.profanityFilterOn account attribute indicated by the /player/attributes Mojang API endpoint. In offline mode it is always false.
			Allow server listings	Boolean	Servers usually list online players, this option should let you not show up in that list.
			Particle Status	VarInt Enum	0: all, 1: decreased, 2: minimal

Displayed Skin Parts flags:

• Bit 0 (0x01): Cape enabled
• Bit 1 (0x02): Jacket enabled
• Bit 2 (0x04): Left Sleeve enabled
• Bit 3 (0x08): Right Sleeve enabled
• Bit 4 (0x10): Left Pants Leg enabled
• Bit 5 (0x20): Right Pants Leg enabled
• Bit 6 (0x40): Hat enabled

The most significant bit (bit 7, 0x80) appears to be unused.

Command Suggestions Request

Sent when the client needs to tab-complete a minecraft:ask_server suggestion type.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0D resource: command_suggestion	Play	Server	Transaction Id	VarInt	The id of the transaction that the server will send back to the client in the response of this packet. Client generates this and increments it each time it sends another tab completion that doesn't get a response.
			Text	String (32500)	All text behind the cursor without the / (e.g. to the left of the cursor in left-to-right languages like English).

Acknowledge Configuration

Sent by the client upon receiving a Start Configuration packet from the server.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0E resource: configuration_acknowledged	Play	Server	no fields

This packet switches the connection state to configuration.

Click Container Button

Used when clicking on window buttons. Until 1.14, this was only used by enchantment tables.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x0F resource: container_button_click	Play	Server	Window ID	VarInt	The ID of the window sent by Open Screen.
			Button ID	VarInt	Meaning depends on window type; see below.

Window type	ID	Meaning
Enchantment Table	0	Topmost enchantment.
	1	Middle enchantment.
	2	Bottom enchantment.
Lectern	1	Previous page (which does give a redstone output).
	2	Next page.
	3	Take Book.
	100+page	Opened page number - 100 + number.
Stonecutter	Recipe button number - 4*row + col. Depends on the item.
Loom	Recipe button number - 4*row + col. Depends on the item.

Click Container

This packet is sent by the client when the player clicks on a slot in a window.

Packet ID	State	Bound To	Field Name		Field Type		Notes
protocol: 0x10 resource: container_click	Play	Server	Window ID		VarInt		The ID of the window which was clicked. 0 for player inventory. The server ignores any packets targeting a Window ID other than the current one, including ignoring 0 when any other window is open.
			State ID		VarInt		The last received State ID from either a Set Container Slot or a Set Container Content packet.
			Slot		Short		The clicked slot number, see below.
			Button		Byte		The button used in the click, see below.
			Mode		VarInt Enum		Inventory operation mode, see below.
			Array of changed slots	Slot number	Prefixed Array (128)	Short
				Slot data		Slot	New data for this slot, in the client's opinion; see below.
			Carried item		Slot		Item carried by the cursor. Has to be empty (item ID = -1) for drop mode, otherwise nothing will happen.

See Inventory for further information about how slots are indexed.

After performing the action, the server compares the results to the slot change information included in the packet, as applied on top of the server's view of the container's state prior to the action. For any slots that do not match, it sends Set Container Slot packets containing the correct results. If State ID does not match the last ID sent by the server, it will instead send a full Set Container Content to resynchronize the client.

When right-clicking on a stack of items, half the stack will be picked up and half left in the slot. If the stack is an odd number, the half left in the slot will be smaller of the amounts.

The distinct type of click performed by the client is determined by the combination of the Mode and Button fields.

Mode	Button	Slot	Trigger
0	0	Normal	Left mouse click
	1	Normal	Right mouse click
	0	-999	Left click outside inventory (drop cursor stack)
	1	-999	Right click outside inventory (drop cursor single item)
1	0	Normal	Shift + left mouse click
	1	Normal	Shift + right mouse click (identical behavior)
2	0	Normal	Number key 1
	1	Normal	Number key 2
	2	Normal	Number key 3
	⋮	⋮	⋮
	8	Normal	Number key 9
	⋮	⋮	Button is used as the slot index (impossible in vanilla clients)
	40	Normal	Offhand swap key F
3	2	Normal	Middle click, only defined for creative players in non-player inventories.
4	0	Normal	Drop key (Q)
	1	Normal	Control + Drop key (Q)
5	0	-999	Starting left mouse drag
	4	-999	Starting right mouse drag
	8	-999	Starting middle mouse drag, only defined for creative players in non-player inventories.
	1	Normal	Add slot for left-mouse drag
	5	Normal	Add slot for right-mouse drag
	9	Normal	Add slot for middle-mouse drag, only defined for creative players in non-player inventories.
	2	-999	Ending left mouse drag
	6	-999	Ending right mouse drag
	10	-999	Ending middle mouse drag, only defined for creative players in non-player inventories.
6	0	Normal	Double click
	1	Normal	Pickup all but check items in reverse order (impossible in vanilla clients)

Starting from version 1.5, “painting mode” is available for use in inventory windows. It is done by picking up stack of something (more than 1 item), then holding mouse button (left, right or middle) and dragging held stack over empty (or same type in case of right button) slots. In that case client sends the following to server after mouse button release (omitting first pickup packet which is sent as usual):

1. packet with mode 5, slot -999, button (0 for left | 4 for right);
2. packet for every slot painted on, mode is still 5, button (1 | 5);
3. packet with mode 5, slot -999, button (2 | 6);

If any of the painting packets other than the “progress” ones are sent out of order (for example, a start, some slots, then another start; or a left-click in the middle) the painting status will be reset.

Close Container

This packet is sent by the client when closing a window.

vanilla clients send a Close Window packet with Window ID 0 to close their inventory even though there is never an Open Screen packet for the inventory.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x11 resource: container_close	Play	Server	Window ID	VarInt	This is the ID of the window that was closed. 0 for player inventory.

Change Container Slot State

This packet is sent by the client when toggling the state of a Crafter.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x12 resource: container_slot_state_changed	Play	Server	Slot ID	VarInt	This is the ID of the slot that was changed.
			Window ID	VarInt	This is the ID of the window that was changed.
			State	Boolean	The new state of the slot. True for enabled, false for disabled.

Cookie Response (play)

Response to a Cookie Request (play) from the server. The vanilla server only accepts responses of up to 5 kiB in size.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x13 resource: cookie_response	Play	Server	Key	Identifier	The identifier of the cookie.
			Payload	Prefixed Optional Prefixed Array (5120) of Byte	The data of the cookie.

Serverbound Plugin Message (play)

Mods and plugins can use this to send their data. Minecraft itself uses some plugin channels. These internal channels are in the minecraft namespace.

More documentation on this: https://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/

Note that the length of Data is known only from the packet length, since the packet has no length field of any kind.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x14 resource: custom_payload	Play	Server	Channel	Identifier	Name of the plugin channel used to send the data.
			Data	Byte Array (32767)	Any data, depending on the channel. minecraft: channels are documented here. The length of this array must be inferred from the packet length.

In vanilla servers, the maximum data length is 32767 bytes.

Debug Sample Subscription

Subscribes to the specified type of debug sample data, which is then sent periodically to the client via Debug Sample.

The subscription is retained for 10 seconds (the vanilla server checks that both 10.001 real-time seconds and 201 ticks have elapsed), after which the client is automatically unsubscribed. The vanilla client resends this packet every 5 seconds to keep up the subscription.

The vanilla server only allows subscriptions from players that are server operators.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x15 resource: debug_sample_subscription	Play	Server	Sample Type	VarInt Enum	The type of debug sample to subscribe to. Can be one of the following: 0 - Tick time

Edit Book

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x16 resource: edit_book	Play	Server	Slot	VarInt	The hotbar slot where the written book is located
			Entries	Prefixed Array (100) of String (1024)	Text from each page. Maximum string length is 1024 chars.
			Title	Prefixed Optional String (32)	Title of book. Present if book is being signed, not present if book is being edited.

Query Entity Tag

Used when F3+I is pressed while looking at an entity.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x17 resource: entity_tag_query	Play	Server	Transaction ID	VarInt	An incremental ID so that the client can verify that the response matches.
			Entity ID	VarInt	The ID of the entity to query.

Interact

This packet is sent from the client to the server when the client attacks or right-clicks another entity (a player, minecart, etc).

A vanilla server only accepts this packet if the entity being attacked/used is visible without obstruction and within a 4-unit radius of the player's position.

The target X, Y, and Z fields represent the difference between the vector location of the cursor at the time of the packet and the entity's position.

Note that middle-click in creative mode is interpreted by the client and sent as a Set Creative Mode Slot packet instead.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x18 resource: interact	Play	Server	Entity ID	VarInt	The ID of the entity to interact. Note the special case described below.
			Type	VarInt Enum	0: interact, 1: attack, 2: interact at.
			Target X	Optional Float	Only if Type is interact at.
			Target Y	Optional Float	Only if Type is interact at.
			Target Z	Optional Float	Only if Type is interact at.
			Hand	Optional VarInt Enum	Only if Type is interact or interact at; 0: main hand, 1: off hand.
			Sneak Key Pressed	Boolean	If the client is pressing the sneak key. Has the same effect as a Player Command Press/Release sneak key preceding the interaction, and the state is permanently changed.

Interaction with the ender dragon is an odd special case characteristic of release deadline–driven design. 8 consecutive entity IDs following the dragon's ID (id + 1, id + 2, ..., id + 8) are reserved for the 8 hitboxes that make up the dragon:

ID offset	Description
0	The dragon itself (never used in this packet)
1	Head
2	Neck
3	Body
4	Tail 1
5	Tail 2
6	Tail 3
7	Wing 1
8	Wing 2

Jigsaw Generate

Sent when Generate is pressed on the Jigsaw Block interface.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x19 resource: jigsaw_generate	Play	Server	Location	Position	Block entity location.
			Levels	VarInt	Value of the levels slider/max depth to generate.
			Keep Jigsaws	Boolean

Serverbound Keep Alive (play)

The server will frequently send out a keep-alive (see Clientbound Keep Alive), each containing a random ID. The client must respond with the same packet.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1A resource: keep_alive	Play	Server	Keep Alive ID	Long

Lock Difficulty

Must have at least op level 2 to use. Appears to only be used on singleplayer; the difficulty buttons are still disabled in multiplayer.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1B resource: lock_difficulty	Play	Server	Locked	Boolean

Set Player Position

Updates the player's XYZ position on the server.

If the player is in a vehicle, the position is ignored (but in case of Set Player Position and Rotation, the rotation is still used as normal). No validation steps other than value range clamping are performed in this case.

If the player is sleeping, the position (or rotation) is not changed, and a Synchronize Player Position is sent if the received position deviated from the server's view by more than a meter.

The vanilla server silently clamps the x and z coordinates between -30,000,000 and 30,000,000, and the y coordinate between -20,000,000 and 20,000,000. A similar condition has historically caused a kick for "Illegal position"; this is no longer the case. However, infinite or NaN coordinates (or angles) still result in a kick for multiplayer.disconnect.invalid_player_movement.

As of 1.20.6, checking for moving too fast is achieved like this (sic):

• Each server tick, the player's current position is stored.
• When the player moves, the offset from the stored position to the requested position is computed (Δx, Δy, Δz).
• The requested movement distance squared is computed as Δx² + Δy² + Δz².
• The baseline expected movement distance squared is computed based on the player's server-side velocity as Vx² + Vy² + Vz². The player's server-side velocity is a somewhat ill-defined quantity that includes among other things gravity, jump velocity and knockback, but not regular horizontal movement. A proper description would bring much of Minecraft's physics engine with it. It is accessible as the Motion NBT tag on the player entity.
• The maximum permitted movement distance squared is computed as 100 (300 if the player is using an elytra), multiplied by the number of movement packets received since the last tick, including this one, unless that value is greater than 5, in which case no multiplier is applied.
• If the requested movement distance squared minus the baseline distance squared is more than the maximum squared, the player is moving too fast.

If the player is moving too fast, it is logged that "<player> moved too quickly! " followed by the change in x, y, and z, and the player is teleported back to their current (before this packet) server-side position.

Checking for block collisions is achieved like this:

• A temporary collision-checked move of the player is attempted from its current position to the requested one.
• The offset from the resulting position to the requested position is computed. If the absolute value of the offset on the y axis is less than 0.5, it (only the y component) is rounded down to 0.
• If the magnitude of the offset is greater than 0.25 and the player isn't in creative or spectator mode, it is logged that "<player> moved wrongly!", and the player is teleported back to their current (before this packet) server-side position.
• In addition, if the player's hitbox stationary at the requested position would intersect with a block, and they aren't in spectator mode, they are teleported back without a log message.

Checking for illegal flight is achieved like this:

• When a movement packet is received, a flag indicating whether or not the player is floating mid-air is updated. The flag is set if the move test described above detected no collision below the player and the y component of the offset from the player's current position to the requested one is greater than -0.5, unless any of various conditions permitting flight (creative mode, elytra, levitation effect, etc., but not jumping) are met.
• Each server tick, it is checked if the flag has been set for more than 80 consecutive ticks. If so, and the player isn't currently sleeping, dead or riding a vehicle, they are kicked for multiplayer.disconnect.flying.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1C resource: move_player_pos	Play	Server	X	Double	Absolute position.
			Feet Y	Double	Absolute feet position, normally Head Y - 1.62.
			Z	Double	Absolute position.
			Flags	Byte	Bit field: 0x01: on ground, 0x02: pushing against wall.

Set Player Position and Rotation

A combination of Move Player Rotation and Move Player Position.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1D resource: move_player_pos_rot	Play	Server	X	Double	Absolute position.
			Feet Y	Double	Absolute feet position, normally Head Y - 1.62.
			Z	Double	Absolute position.
			Yaw	Float	Absolute rotation on the X Axis, in degrees.
			Pitch	Float	Absolute rotation on the Y Axis, in degrees.
			Flags	Byte	Bit field: 0x01: on ground, 0x02: pushing against wall.

Set Player Rotation

The unit circle for yaw

The unit circle of yaw, redrawn

Updates the direction the player is looking in.

Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the XZ-plane starts at (0, 1) and turns counterclockwise, with 90 at (-1, 0), 180 at (0,-1) and 270 at (1, 0). Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360.

Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.

The yaw and pitch of player (in degrees), standing at point (x0, y0, z0) and looking towards point (x, y, z) can be calculated with:

dx = x-x0
dy = y-y0
dz = z-z0
r = sqrt( dx*dx + dy*dy + dz*dz )
yaw = -atan2(dx,dz)/PI*180
if yaw < 0 then
    yaw = 360 + yaw
pitch = -arcsin(dy/r)/PI*180

You can get a unit vector from a given yaw/pitch via:

x = -cos(pitch) * sin(yaw)
y = -sin(pitch)
z =  cos(pitch) * cos(yaw)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1E resource: move_player_rot	Play	Server	Yaw	Float	Absolute rotation on the X Axis, in degrees.
			Pitch	Float	Absolute rotation on the Y Axis, in degrees.
			Flags	Byte	Bit field: 0x01: on ground, 0x02: pushing against wall.

Set Player Movement Flags

This packet as well as Set Player Position, Set Player Rotation, and Set Player Position and Rotation are called the “serverbound movement packets”. Vanilla clients will send Move Player Position once every 20 ticks even for a stationary player.

This packet is used to indicate whether the player is on ground (walking/swimming), or airborne (jumping/falling).

When dropping from sufficient height, fall damage is applied when this state goes from false to true. The amount of damage applied is based on the point where it last changed from true to false. Note that there are several movement related packets containing this state.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x1F resource: move_player_status_only	Play	Server	Flags	Byte	Bit field: 0x01: on ground, 0x02: pushing against wall.

Move Vehicle

Sent when a player moves in a vehicle. Fields are the same as in Set Player Position and Rotation. Note that all fields use absolute positioning and do not allow for relative positioning.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x20 resource: move_vehicle	Play	Server	X	Double	Absolute position (X coordinate).
			Y	Double	Absolute position (Y coordinate).
			Z	Double	Absolute position (Z coordinate).
			Yaw	Float	Absolute rotation on the vertical axis, in degrees.
			Pitch	Float	Absolute rotation on the horizontal axis, in degrees.
			On Ground	Boolean	(This value does not seem to exist)

Paddle Boat

Used to visually update whether boat paddles are turning. The server will update the Boat entity metadata to match the values here.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x21 resource: paddle_boat	Play	Server	Left paddle turning	Boolean
			Right paddle turning	Boolean

Right paddle turning is set to true when the left button or forward button is held, left paddle turning is set to true when the right button or forward button is held.

Pick Item From Block

Used for pick block functionality (middle click) on blocks to retrieve items from the inventory in survival or creative mode or create them in creative mode. See Controls#Pick_Block for more information.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x22 resource: pick_item_from_block	Play	Server	Location	Position	The location of the block.
			Include Data	Boolean	Used to tell the server to include block data in the new stack, works only if in creative mode.

Pick Item From Entity

Used for pick block functionality (middle click) on entities to retrieve items from the inventory in survival or creative mode or create them in creative mode. See Controls#Pick_Block for more information.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x23 resource: pick_item_from_entity	Play	Server	Entity ID	VarInt	The ID of the entity to pick.
			Include Data	Boolean	Unused by the vanilla server.

Ping Request (play)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x24 resource: ping_request	Play	Server	Payload	Long	May be any number. vanilla clients use a system-dependent time value which is counted in milliseconds.

Place Recipe

This packet is sent when a player clicks a recipe in the crafting book that is craftable (white border).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x25 resource: place_recipe	Play	Server	Window ID	VarInt
			Recipe ID	VarInt	ID of recipe previously defined in Recipe Book Add.
			Make all	Boolean	Affects the amount of items processed; true if shift is down when clicked.

Player Abilities (serverbound)

The vanilla client sends this packet when the player starts/stops flying with the Flags parameter changed accordingly.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x26 resource: player_abilities	Play	Server	Flags	Byte	Bit mask. 0x02: is flying.

Player Action

Sent when the player mines a block. A vanilla server only accepts digging packets with coordinates within a 6-unit radius between the center of the block and the player's eyes.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x27 resource: player_action	Play	Server	Status	VarInt Enum	The action the player is taking against the block (see below).
			Location	Position	Block position.
			Face	Byte Enum	The face being hit (see below).
			Sequence	VarInt	Block change sequence number (see #Acknowledge Block Change).

Status can be one of seven values:

Value	Meaning	Notes
0	Started digging	Sent when the player starts digging a block. If the block was instamined or the player is in creative mode, the client will not send Status = Finished digging, and will assume the server completed the destruction. To detect this, it is necessary to calculate the block destruction speed server-side.
1	Cancelled digging	Sent when the player lets go of the Mine Block key (default: left click). Face is always set to -Y.
2	Finished digging	Sent when the client thinks it is finished.
3	Drop item stack	Triggered by using the Drop Item key (default: Q) with the modifier to drop the entire selected stack (default: Control or Command, depending on OS). Location is always set to 0/0/0, Face is always set to -Y. Sequence is always set to 0.
4	Drop item	Triggered by using the Drop Item key (default: Q). Location is always set to 0/0/0, Face is always set to -Y. Sequence is always set to 0.
5	Shoot arrow / finish eating	Indicates that the currently held item should have its state updated such as eating food, pulling back bows, using buckets, etc. Location is always set to 0/0/0, Face is always set to -Y. Sequence is always set to 0.
6	Swap item in hand	Used to swap or assign an item to the second hand. Location is always set to 0/0/0, Face is always set to -Y. Sequence is always set to 0.

The Face field can be one of the following values, representing the face being hit:

Value	Offset	Face
0	-Y	Bottom
1	+Y	Top
2	-Z	North
3	+Z	South
4	-X	West
5	+X	East

Player Command

Sent by the client to indicate that it has performed certain actions: sneaking (crouching), sprinting, exiting a bed, jumping with a horse, and opening a horse's inventory while riding it.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x28 resource: player_command	Play	Server	Entity ID	VarInt	Player ID (ignored by the vanilla server)
			Action ID	VarInt Enum	The ID of the action, see below.
			Jump Boost	VarInt	Only used by the “start jump with horse” action, in which case it ranges from 0 to 100. In all other cases it is 0.

Action ID can be one of the following values:

ID	Action
0	Press sneak key
1	Release sneak key
2	Leave bed
3	Start sprinting
4	Stop sprinting
5	Start jump with horse
6	Stop jump with horse
7	Open vehicle inventory
8	Start flying with elytra

Leave bed is only sent when the “Leave Bed” button is clicked on the sleep GUI, not when waking up in the morning.

Open vehicle inventory is only sent when pressing the inventory key (default: E) while on a horse or chest boat — all other methods of opening such an inventory (involving right-clicking or shift-right-clicking it) do not use this packet.

Player Input

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x29 resource: player_input	Play	Server	Flags	Unsigned Byte	Bit mask; see below

The flags are as follows:

Hex Mask	Field
0x01	Forward
0x02	Backward
0x04	Left
0x08	Right
0x10	Jump
0x20	Sneak
0x40	Sprint

Player Loaded

Sent by the client after the server starts sending chunks and the player's chunk has loaded.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2A resource: player_loaded	Play	Server	no fields

Pong (play)

Response to the clientbound packet (Ping) with the same id.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2B resource: pong	Play	Server	ID	Int	id is the same as the ping packet

Change Recipe Book Settings

Replaces Recipe Book Data, type 1.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2C resource: recipe_book_change_settings	Play	Server	Book ID	VarInt Enum	0: crafting, 1: furnace, 2: blast furnace, 3: smoker.
			Book Open	Boolean
			Filter Active	Boolean

Set Seen Recipe

Sent when recipe is first seen in recipe book. Replaces Recipe Book Data, type 0.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2D resource: recipe_book_seen_recipe	Play	Server	Recipe ID	VarInt	ID of recipe previously defined in Recipe Book Add.

Rename Item

Sent as a player is renaming an item in an anvil (each keypress in the anvil UI sends a new Rename Item packet). If the new name is empty, then the item loses its custom name (this is different from setting the custom name to the normal name of the item). The item name may be no longer than 50 characters long, and if it is longer than that, then the rename is silently ignored.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2E resource: rename_item	Play	Server	Item name	String (32767)	The new name of the item.

Resource Pack Response (play)

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x2F resource: resource_pack	Play	Server	UUID	UUID	The unique identifier of the resource pack received in the Add Resource Pack (play) request.
			Result	VarInt Enum	Result ID (see below).

Result can be one of the following values:

ID	Result
0	Successfully downloaded
1	Declined
2	Failed to download
3	Accepted
4	Downloaded
5	Invalid URL
6	Failed to reload
7	Discarded

Seen Advancements

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x30 resource: seen_advancements	Play	Server	Action	VarInt Enum	0: Opened tab, 1: Closed screen.
			Tab ID	Optional Identifier	Only present if action is Opened tab.

Select Trade

When a player selects a specific trade offered by a villager NPC.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x31 resource: select_trade	Play	Server	Selected slot	VarInt	The selected slot in the players current (trading) inventory.

Set Beacon Effect

Changes the effect of the current beacon.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x32 resource: set_beacon	Play	Server	Primary Effect	Prefixed Optional VarInt	A Potion ID.
			Secondary Effect	Prefixed Optional VarInt	A Potion ID.

Set Held Item (serverbound)

Sent when the player changes the slot selection.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x33 resource: set_carried_item	Play	Server	Slot	Short	The slot which the player has selected (0–8).

Program Command Block

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x34 resource: set_command_block	Play	Server	Location	Position
			Command	String (32767)
			Mode	VarInt Enum	0: chain, 1: repeating, 2: impulse.
			Flags	Byte	0x01: Track Output (if false, the output of the previous command will not be stored within the command block); 0x02: Is conditional; 0x04: Automatic.

Program Command Block Minecart

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x35 resource: set_command_minecart	Play	Server	Entity ID	VarInt
			Command	String (32767)
			Track Output	Boolean	If false, the output of the previous command will not be stored within the command block.

Set Creative Mode Slot

While the user is in the standard inventory (i.e., not a crafting bench) in Creative mode, the player will send this packet.

Clicking in the creative inventory menu is quite different from non-creative inventory management. Picking up an item with the mouse actually deletes the item from the server, and placing an item into a slot or dropping it out of the inventory actually tells the server to create the item from scratch. (This can be verified by clicking an item that you don't mind deleting, then severing the connection to the server; the item will be nowhere to be found when you log back in.) As a result of this implementation strategy, the "Destroy Item" slot is just a client-side implementation detail that means "I don't intend to recreate this item.". Additionally, the long listings of items (by category, etc.) are a client-side interface for choosing which item to create. Picking up an item from such listings sends no packets to the server; only when you put it somewhere does it tell the server to create the item in that location.

This action can be described as "set inventory slot". Picking up an item sets the slot to item ID -1. Placing an item into an inventory slot sets the slot to the specified item. Dropping an item (by clicking outside the window) effectively sets slot -1 to the specified item, which causes the server to spawn the item entity, etc.. All other inventory slots are numbered the same as the non-creative inventory (including slots for the 2x2 crafting menu, even though they aren't visible in the vanilla client).

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x36 resource: set_creative_mode_slot	Play	Server	Slot	Short	Inventory slot.
			Clicked Item	Slot

Program Jigsaw Block

Sent when Done is pressed on the Jigsaw Block interface.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x37 resource: set_jigsaw_block	Play	Server	Location	Position	Block entity location
			Name	Identifier
			Target	Identifier
			Pool	Identifier
			Final state	String (32767)	"Turns into" on the GUI, final_state in NBT.
			Joint type	String (32767)	rollable if the attached piece can be rotated, else aligned.
			Selection priority	VarInt
			Placement priority	VarInt

Program Structure Block

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x38 resource: set_structure_block	Play	Server
			Location	Position	Block entity location.
			Action	VarInt Enum	An additional action to perform beyond simply saving the given data; see below.
			Mode	VarInt Enum	One of SAVE (0), LOAD (1), CORNER (2), DATA (3).
			Name	String (32767)
			Offset X	Byte	Between -48 and 48.
			Offset Y	Byte	Between -48 and 48.
			Offset Z	Byte	Between -48 and 48.
			Size X	Byte	Between 0 and 48.
			Size Y	Byte	Between 0 and 48.
			Size Z	Byte	Between 0 and 48.
			Mirror	VarInt Enum	One of NONE (0), LEFT_RIGHT (1), FRONT_BACK (2).
			Rotation	VarInt Enum	One of NONE (0), CLOCKWISE_90 (1), CLOCKWISE_180 (2), COUNTERCLOCKWISE_90 (3).
			Metadata	String (128)
			Integrity	Float	Between 0 and 1.
			Seed	VarLong
			Flags	Byte	0x01: Ignore entities; 0x02: Show air; 0x04: Show bounding box.

Possible actions:

• 0 - Update data
• 1 - Save the structure
• 2 - Load the structure
• 3 - Detect size

The vanilla client uses update data to indicate no special action should be taken (i.e. the done button).

Update Sign

This message is sent from the client to the server when the “Done” button is pushed after placing a sign.

The server only accepts this packet after Open Sign Editor, otherwise this packet is silently ignored.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x39 resource: sign_update	Play	Server	Location	Position	Block Coordinates.
			Is Front Text	Boolean	Whether the updated text is in front or on the back of the sign
			Line 1	String (384)	First line of text in the sign.
			Line 2	String (384)	Second line of text in the sign.
			Line 3	String (384)	Third line of text in the sign.
			Line 4	String (384)	Fourth line of text in the sign.

Swing Arm

Sent when the player's arm swings.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3A resource: swing	Play	Server	Hand	VarInt Enum	Hand used for the animation. 0: main hand, 1: off hand.

Teleport To Entity

Teleports the player to the given entity. The player must be in spectator mode.

The vanilla client only uses this to teleport to players, but it appears to accept any type of entity. The entity does not need to be in the same dimension as the player; if necessary, the player will be respawned in the right world. If the given entity cannot be found (or isn't loaded), this packet will be ignored.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3B resource: teleport_to_entity	Play	Server	Target Player	UUID	UUID of the player to teleport to (can also be an entity UUID).

Use Item On

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3C resource: use_item_on	Play	Server	Hand	VarInt Enum	The hand from which the block is placed; 0: main hand, 1: off hand.
			Location	Position	Block position.
			Face	VarInt Enum	The face on which the block is placed (as documented at Player Action).
			Cursor Position X	Float	The position of the crosshair on the block, from 0 to 1 increasing from west to east.
			Cursor Position Y	Float	The position of the crosshair on the block, from 0 to 1 increasing from bottom to top.
			Cursor Position Z	Float	The position of the crosshair on the block, from 0 to 1 increasing from north to south.
			Inside block	Boolean	True when the player's head is inside of a block.
			World Border Hit	Boolean	Seems to always be false, even when interacting with blocks around or outside the world border, or while the player is outside the border.
			Sequence	VarInt	Block change sequence number (see #Acknowledge Block Change).

Upon placing a block, this packet is sent once.

The Cursor Position X/Y/Z fields (also known as in-block coordinates) are calculated using raytracing. The unit corresponds to sixteen pixels in the default resource pack. For example, let's say a slab is being placed against the south face of a full block. The Cursor Position X will be higher if the player was pointing near the right (east) edge of the face, lower if pointing near the left. The Cursor Position Y will be used to determine whether it will appear as a bottom slab (values 0.0–0.5) or as a top slab (values 0.5-1.0). The Cursor Position Z should be 1.0 since the player was looking at the southernmost part of the block.

Inside block is true when a player's head (specifically eyes) are inside of a block's collision. In 1.13 and later versions, collision is rather complicated and individual blocks can have multiple collision boxes. For instance, a ring of vines has a non-colliding hole in the middle. This value is only true when the player is directly in the box. In practice, though, this value is only used by scaffolding to place in front of the player when sneaking inside of it (other blocks will place behind when you intersect with them -- try with glass for instance).

Use Item

Sent when pressing the Use Item key (default: right click) with an item in hand.

Packet ID	State	Bound To	Field Name	Field Type	Notes
protocol: 0x3D resource: use_item	Play	Server	Hand	VarInt Enum	Hand used for the animation. 0: main hand, 1: off hand.
			Sequence	VarInt	Block change sequence number (see #Acknowledge Block Change).
			Yaw	Float	Player head rotation along the Y-Axis.
			Pitch	Float	Player head rotation along the X-Axis.

The player's rotation is permanently updated according to the Yaw and Pitch fields before performing the action, unless there is no item in the specified hand.