Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.20.2, protocol 764) to the current pre-release (currently 23w45a, protocol Snapshot 162). 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.

Name	Size (bytes)	Encodes	Notes
Chat	≥ 1 ≤ (262144×4) + 3	See Chat	Encoded as a String with max length of 262144.
Chat	Varies	See Chat	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.

This affects the following packets and data types containing Chat fields:

However, the following are NOT affected, as to maintain backwards compatibility with older versions:

Particle

Particle Name Particle ID Data

minecraft:ambient_entity_effect 0 None

minecraft:angry_villager 1 None

minecraft:block

2

Field Name	Field Type	Meaning
BlockState	VarInt	The ID of the block state.

minecraft:block_marker

3

Field Name	Field Type	Meaning
BlockState	VarInt	The ID of the block state.

minecraft:bubble 4 None

minecraft:cloud 5 None

minecraft:crit 6 None

minecraft:damage_indicator 7 None

minecraft:dragon_breath 8 None

minecraft:dripping_lava 9 None

minecraft:falling_lava 10 None

minecraft:landing_lava 11 None

minecraft:dripping_water 12 None

minecraft:falling_water 13 None

minecraft:dust

14

Field Name	Field Type	Meaning
Red	Float	The red RGB value, between 0 and 1. Divide actual RGB value by 255.
Green	Float	The green RGB value, between 0 and 1. Divide actual RGB value by 255.
Blue	Float	The blue RGB value, between 0 and 1. Divide actual RGB value by 255.
Scale	Float	The scale, will be clamped between 0.01 and 4.

minecraft:dust_color_transition

15

Field Name	Field Type	Meaning
From Red	Float	The start red RGB value, between 0 and 1. Divide actual RGB value by 255.
From Green	Float	The start green RGB value, between 0 and 1. Divide actual RGB value by 255.
From Blue	Float	The start blue RGB value, between 0 and 1. Divide actual RGB value by 255.
Scale	Float	The scale, will be clamped between 0.01 and 4.
To Red	Float	The end red RGB value, between 0 and 1. Divide actual RGB value by 255.
To Green	Float	The end green RGB value, between 0 and 1. Divide actual RGB value by 255.
To Blue	Float	The end blue RGB value, between 0 and 1. Divide actual RGB value by 255.

minecraft:effect 16 None

minecraft:elder_guardian 17 None

minecraft:enchanted_hit 18 None

minecraft:enchant 19 None

minecraft:end_rod 20 None

minecraft:entity_effect 21 None

minecraft:explosion_emitter 22 None

minecraft:explosion 23 None

minecraft:gust 24 None

minecraft:gust_emitter 25 None

minecraft:sonic_boom 24 26 None

minecraft:falling_dust

25 27

Field Name	Field Type	Meaning
BlockState	VarInt	The ID of the block state.

minecraft:firework 26 28 None

minecraft:fishing 27 29 None

minecraft:flame 28 30 None

minecraft:cherry_leaves 29 31 None

minecraft:sculk_soul 30 32 None

minecraft:sculk_charge

31 33

Field Name	Field Type	Meaning
Roll	Float	How much the particle will be rotated when displayed.

minecraft:sculk_charge_pop 32 34 None

minecraft:soul_fire_flame 33 35 None

minecraft:soul 34 36 None

minecraft:flash 35 37 None

minecraft:happy_villager 36 38 None

minecraft:composter 37 39 None

minecraft:heart 38 40 None

minecraft:instant_effect 39 41 None

minecraft:item

40 42

Field Name	Field Type	Meaning
Item	Slot	The item that will be used.

minecraft:vibration

41 43

Field Name	Field Type	Meaning
Position Source Type	Identifier	The type of the vibration source
Block Position	Position	The position of the block the vibration originated from. Only present if Position Type is `minecraft:block`.
Entity ID	VarInt	The ID of the entity the vibration originated from. Only present if Position Type is `minecraft:entity`.
Entity eye height	Float	The height of the entity's eye relative to the entity. Only present if Position Type is `minecraft:entity`.
Ticks	VarInt	The amount of ticks it takes for the vibration to travel from its source to its destination.

minecraft:item_slime 42 44 None

minecraft:item_snowball 43 45 None

minecraft:large_smoke 44 46 None

minecraft:lava 45 47 None

minecraft:mycelium 46 48 None

minecraft:note 47 49 None

minecraft:poof 48 50 None

minecraft:portal 49 51 None

minecraft:rain 50 52 None

minecraft:smoke 51 53 None

minecraft:white_smoke 54 None

minecraft:sneeze 52 55 None

minecraft:spit 53 56 None

minecraft:squid_ink 54 57 None

minecraft:sweep_attack 55 58 None

minecraft:totem_of_undying 56 59 None

minecraft:underwater 57 60 None

minecraft:splash 58 61 None

minecraft:witch 59 62 None

minecraft:bubble_pop 60 63 None

minecraft:current_down 61 64 None

minecraft:bubble_column_up 62 65 None

minecraft:nautilus 63 66 None

minecraft:dolphin 64 67 None

minecraft:campfire_cosy_smoke 65 68 None

minecraft:campfire_signal_smoke 66 69 None

minecraft:dripping_honey 67 70 None

minecraft:falling_honey 68 71 None

minecraft:landing_honey 69 72 None

minecraft:falling_nectar 70 73 None

minecraft:falling_spore_blossom 71 74 None

minecraft:ash 72 75 None

minecraft:crimson_spore 73 76 None

minecraft:warped_spore 74 77 None

minecraft:spore_blossom_air 75 78 None

minecraft:dripping_obsidian_tear 76 79 None

minecraft:falling_obsidian_tear 77 80 None

minecraft:landing_obsidian_tear 78 81 None

minecraft:reverse_portal 79 82 None

minecraft:white_ash 80 83 None

minecraft:small_flame 81 84 None

minecraft:snowflake 82 85 None

minecraft:dripping_dripstone_lava 83 86 None

minecraft:falling_dripstone_lava 84 87 None

minecraft:dripping_dripstone_water 85 88 None

minecraft:falling_dripstone_water 86 89 None

minecraft:glow_squid_ink 87 90 None

minecraft:glow 88 91 None

minecraft:wax_on 89 92 None

minecraft:wax_off 90 93 None

minecraft:electric_spark 91 94 None

minecraft:scrape 92 95 None

minecraft:shriek

93 96

Field Name	Field Type	Meaning
Delay	VarInt	The time in ticks before the particle is displayed

minecraft:egg_crack 94 97 None

minecraft:dust_plume 98 None

minecraft:gust_dust 99 None

minecraft:trial_spawner_detection 100 None

Packets

ID	Packet name	Documentation
Configuration clientbound
0x07	Feature Flags	Current	Pre
Play clientbound
0x1E	Explosion	Current	Pre
0x20	Game Event	Current	Pre
0x6C	Set Ticking State		Pre
0x6D	Step Tick		Pre
~~0x6C~~ 0x6E	Update Advancements	Current	(unchanged)
~~0x6D~~ 0x6F	Update Attributes	Current	(unchanged)
~~0x6E~~ 0x70	Entity Effect	Current	(unchanged)
~~0x6F~~ 0x71	Update Recipes	Current	(unchanged)
~~0x70~~ 0x72	Update Tags	Current	(unchanged)
Play serverbound
0x0F	Change Container Slot State		Pre
~~0x0F~~ 0x10	Serverbound Plugin Message (play)	Current	(unchanged)
~~0x10~~ 0x11	Edit Book	Current	(unchanged)
~~0x11~~ 0x12	Query Entity Tag	Current	(unchanged)
~~0x12~~ 0x13	Interact	Current	(unchanged)
~~0x13~~ 0x14	Jigsaw Generate	Current	(unchanged)
~~0x14~~ 0x15	Serverbound Keep Alive (play)	Current	(unchanged)
~~0x15~~ 0x16	Lock Difficulty	Current	(unchanged)
~~0x16~~ 0x17	Set Player Position	Current	(unchanged)
~~0x17~~ 0x18	Set Player Position and Rotation	Current	(unchanged)
~~0x18~~ 0x19	Set Player Rotation	Current	(unchanged)
~~0x19~~ 0x1A	Set Player On Ground	Current	(unchanged)
~~0x1A~~ 0x1B	Move Vehicle	Current	(unchanged)
~~0x1B~~ 0x1C	Paddle Boat	Current	(unchanged)
~~0x1C~~ 0x1D	Pick Item	Current	(unchanged)
~~0x1D~~ 0x1E	Ping Request (play)	Current	(unchanged)
~~0x1E~~ 0x1F	Place Recipe	Current	(unchanged)
~~0x1F~~ 0x20	Player Abilities	Current	(unchanged)
~~0x20~~ 0x21	Player Action	Current	(unchanged)
~~0x21~~ 0x22	Player Command	Current	(unchanged)
~~0x22~~ 0x23	Player Input	Current	(unchanged)
~~0x23~~ 0x24	Pong (play)	Current	(unchanged)
~~0x24~~ 0x25	Change Recipe Book Settings	Current	(unchanged)
~~0x25~~ 0x26	Set Seen Recipe	Current	(unchanged)
~~0x26~~ 0x27	Rename Item	Current	(unchanged)
~~0x27~~ 0x28	Resource Pack Response (play)	Current	(unchanged)
~~0x28~~ 0x29	Seen Advancements	Current	(unchanged)
~~0x29~~ 0x2A	Select Trade	Current	(unchanged)
~~0x2A~~ 0x2B	Set Beacon Effect	Current	(unchanged)
~~0x2B~~ 0x2C	Set Held Item	Current	(unchanged)
~~0x2C~~ 0x2D	Program Command Block	Current	(unchanged)
~~0x2D~~ 0x2E	Program Command Block Minecart	Current	(unchanged)
~~0x2E~~ 0x2F	Set Creative Mode Slot	Current	(unchanged)
~~0x2F~~ 0x30	Program Jigsaw Block	Current	Pre
~~0x30~~ 0x31	Program Structure Block	Current	(unchanged)
~~0x31~~ 0x32	Update Sign	Current	(unchanged)
~~0x32~~ 0x33	Swing Arm	Current	(unchanged)
~~0x33~~ 0x34	Teleport To Entity	Current	(unchanged)
~~0x34~~ 0x35	Use Item On	Current	(unchanged)
~~0x35~~ 0x36	Use Item	Current	(unchanged)

New/modified data types

No changes so far.

Entity Metadata

Abstract Vehicle

Extends Entity.

Index	Type	Meaning	Default
8	VarInt	Shaking power	0
9	VarInt	Shaking direction	1
10	Float	Shaking multiplier	0.0

Abstract Minecart

Extends Abstract Vehicle.

Index	Type	Meaning	Default
8	VarInt	Shaking power	0
9	VarInt	Shaking direction	1
10	Float	Shaking multiplier	0.0
11	VarInt	Custom block ID and damage	0
12	VarInt	Custom block Y position (in 16ths of a block)	6
13	Boolean	Show custom block	false

Boat

Extends Abstract Vehicle.

Index	Type	Meaning	Default
8	VarInt	Time since last hit	0
9	VarInt	Forward direction	1
10	Float	Damage taken	0.0
11	VarInt	Type (0=oak, 1=spruce, 2=birch, 3=jungle, 4=acacia, 5=dark oak)	0
12	Boolean	Is left paddle turning	false
13	Boolean	Is right paddle turning	false
14	VarInt	Splash timer	0

Block Actions

No changes so far.

Inventories

No changes so far.

Plugin Channels

No changes so far.

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

No changes so far.

Serverbound

No changes so far.

Configuration

Clientbound

Feature Flags

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

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x07	Configuration	Client	Total Features	VarInt	Number of features that appear in the array below.
0x07	Configuration	Client	Feature Flags	Identifier Array

As of ~~1.20.2~~ 1.20.3, the following feature flags are available:

minecraft:vanilla - enables vanilla features
minecraft:bundle - enables support for the bundle
minecraft:trade_rebalance - enables support for the rebalanced villager trades
minecraft:update_1_21 - enables support for 1.21 features

Serverbound

No changes so far.

Play

Clientbound

Explosion

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

Each block in Records is set to air. Coordinates for each axis in record is int(X) + record.x

There is currently a disparity in the Notchian implementation between the data that is read from and written to the network. The write logic only serializes the particle id for the fields Small explosion particle and Large explosion particle, while the read logic expects the particle id and extra required data. See MC-266537 for more information.

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x1E	Play	Client	X		Double
			Y		Double
			Z		Double
			Strength		Float	~~A strength greater than or equal to 2.0 spawns a `minecraft:explosion_emitter` particle, while a lesser strength spawns a `minecraft:explosion` particle.~~ If the strength is greater or equal to 2.0, or the block interaction is not 0 (keep), large explosion particles are used. Otherwise, small explosion particles are used.
			Record Count		VarInt	Number of elements in the following array.
			Records		Array of (Byte, Byte, Byte)	Each record is 3 signed bytes long; the 3 bytes are the XYZ (respectively) signed offsets of affected blocks.
			Player Motion X		Float	X velocity of the player being pushed by the explosion.
			Player Motion Y		Float	Y velocity of the player being pushed by the explosion.
			Player Motion Z		Float	Z velocity of the player being pushed by the explosion.
			Block interaction		VarInt Enum	0 = keep, 1 = destroy, 2 = destroy_with_decay, 3 = trigger_block.
			Small explosion particle		VarInt	The particle ID listed in the particle data type.
			Large explosion particle		VarInt	The particle ID listed in the particle data type.
			Explosion sound	Sound Name	Identifier	The name of the sound played.
				Has Fixed Range	Optional Boolean	Whether is has fixed range.
				Range	Optional Float	The fixed range of the sound. Only present if previous boolean is true.

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
0x20	Play	Client	Event	Unsigned Byte	See below.
0x20	Play	Client	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 notchian 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 notchian 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).

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
0x6C	Play	Server	Tick rate	Float
0x6C	Play	Server	Is frozen	Boolean

Step Tick

Advances the client processing by the specified number of ticks. Has no effect is the client ticking is not frozen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x6D	Play	Client	Tick steps	VarInt

Serverbound

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
0x0F	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.

Program Jigsaw Block

Sent when Done is pressed on the Jigsaw Block interface.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x2F	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

Pre-release protocol

Contents

Contents

Data types

NBT

Chat

Particle

Packets

New/modified data types

Entity Metadata

Abstract Vehicle

Abstract Minecart

Boat

Block Actions

Inventories

Plugin Channels

Status

Clientbound

Serverbound

Login

Clientbound

Serverbound

Configuration

Clientbound

Feature Flags

Serverbound

Play

Clientbound

Explosion

Game Event

Set Ticking State

Step Tick

Serverbound

Change Container Slot State

Program Jigsaw Block

Navigation menu

Search