Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.8.8, protocol 47) to the current pre-release (currently 15w31a, protocol 49). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

One who wishes to commandeer the merging of this into Protocol when an update is made must be sure to respect any changes that may have occurred to the respective packets there.

Protocol history

None so far.

New/modified data types

None so far.

Handshaking

Clientbound

No changes so far.

Serverbound

Handshake

This causes the server to switch into the target state.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Handshaking	Server	Protocol Version	VarInt	See protocol version numbers (currently 47 49)
			Server Address	String	hostname or IP, e.g. localhost or 127.0.0.1
			Server Port	Unsigned Short	default is 25565
			Next State	VarInt	1 for status, 2 for login

Play

Clientbound

No changes so far.

Serverbound

Player Digging

Sent when the player mines a block. A Notchian server only accepts digging packets with coordinates within a 6-unit radius of the player's position.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x07	Play	Server	Status	Byte	The action the player is taking against the block (see below)
			Location	Position	Block position
			Face	Byte	The face being hit (see below)

Status can (currently) be one of six values:

Meaning	Value
Started digging	0
Cancelled digging	1
Finished digging	2
Drop item stack	3
Drop item	4
Shoot arrow / finish eating	5
Swap item in Hand	6

Notchian clients send a 0 (started digging) when they start digging and a 2 (finished digging) once they think they are finished. If digging is aborted, the client simply send a 1 (cancel digging).

Status code 4 (drop item) is a special case. In-game, when you use the Drop Item command (keypress 'q'), a dig packet with a status of 4, and all other values set to 0, is sent from client to server. Status code 3 is similar, but drops the entire stack.

Status code 5 (shoot arrow / finish eating) is also a special case. The x, y and z fields are all set to 0 like above, with the exception of the face field, which is set to 255.

Status code 6 is another special case. Used to swap or assign an item to the second hand. The rest of the fields (x, y, z and face) are all set to 0.

The face can be one of six values, representing the face being hit:

Value	0	1	2	3	4	5
Offset	-Y	+Y	-Z	+Z	-X	+X

Held Item Change

Sent when the player changes the slot selection

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x09 0x0A	Play	Server	Slot	Short	The slot which the player has selected (0–8)

Animation

Sent when the player's arm swings

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0A 0x0B	Play	Server	Hand	Byte	Hand used for the animation.

Entity Action

Sent at least when crouching, leaving a bed, or sprinting. To send action animation to client use 0x28. The client will send this with Action ID = 3 when “Leave Bed” is clicked.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0B 0x0C	Play	Server	Entity ID	VarInt	Player ID
			Action ID	VarInt	The ID of the action, see below
			Jump Boost	VarInt	Horse jump boost. Ranged from 0 -> 100.

Action ID can be one of the following values:

ID	Action
0	Crouch
1	Uncrouch
2	Leave bed
3	Start sprinting
4	Stop sprinting
5	Jump with horse
6	Open inventory

Steer Vehicle

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x0C 0x0D	Play	Server	Sideways	Float	Positive to the left of the player
			Forward	Float	Positive forward
			Flags	Unsigned Byte	Bit mask. 0x1: jump, 0x2: unmount

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

No changes so far.

Serverbound

No changes so far.