Fabric Package Logger

A deep packet logging mod for Minecraft Fabric that captures all network traffic (S2C and C2S) with full NBT/Component data.

Use Cases

Mod Development: Debug network communication between client and server
Container Inspection: View exact contents of inventories with full NBT/Component data and copying them
Reverse Engineering: Analyze server-side mechanics and packet structures
Anti-Cheat Analysis: Understand what data the server sends and receives
Learning: Understand how Minecraft's network protocol works

Usage

Keybind

Press F6 to open the config screen.

Packet Selection

Use the dual-list selector to choose which packets to log:

S2C (Server → Client): Incoming packets like inventory updates, entity spawns, etc.
C2S (Client → Server): Outgoing packets like clicks, movements, etc.

Log Modes

Chat: Display packets in the game chat (truncated for readability)
File: Save packets to log files with full data

Log Files

Logs are saved to:

MINECRAFT_FOLDER/packet-logger/packets_2026-01-04_15-30-45_servername.log

A new log file is created when:

Joining a world/server
Re-enabling logging after it was disabled

Example Output

[12:34:56.789] [S2C] InventoryS2CPacket {syncId:2,revision:1,id:"minecraft:generic_9x3",components:{"minecraft:container":[{item:{id:"minecraft:diamond_sword",count:1,components:{"minecraft:enchantments":{levels:{"minecraft:sharpness":5}}}},slot:0}]}}

Settings GUI / Package selection

Available Packets

All packets are loaded dynamically from the game's PacketType registries and are selectable in the config screen's dual-list selector. Both S2C (Server → Client) and C2S (Client → Server) packets are covered across all protocol phases.

See for an example listing of all packets for Minecraft 1.21.4.

Click to expand (573 packets)

S2C (Server → Client)

Common

CommonPingS2CPacket
CookieRequestS2CPacket
CustomPayloadS2CPacket
CustomReportDetailsS2CPacket
DisconnectS2CPacket
KeepAliveS2CPacket
ResourcePackRemoveS2CPacket
ResourcePackSendS2CPacket
ServerLinksS2CPacket
ServerTransferS2CPacket
StoreCookieS2CPacket
SynchronizeTagsS2CPacket

Config

DynamicRegistriesS2CPacket
FeaturesS2CPacket
ReadyS2CPacket
ResetChatS2CPacket
SelectKnownPacksS2CPacket

Custom

DebugBeeCustomPayload
- Bee
DebugBrainCustomPayload
- Brain
DebugBreezeCustomPayload
- BreezeInfo
DebugGameEventCustomPayload
DebugGameEventListenersCustomPayload
DebugGameTestAddMarkerCustomPayload
DebugGameTestClearCustomPayload
DebugGoalSelectorCustomPayload
- Goal
DebugHiveCustomPayload
- HiveInfo
DebugNeighborsUpdateCustomPayload
DebugPathCustomPayload
DebugPoiAddedCustomPayload
DebugPoiRemovedCustomPayload
DebugPoiTicketCountCustomPayload
DebugRaidsCustomPayload
DebugRedstoneUpdateOrderCustomPayload
- Wire
DebugStructuresCustomPayload
- Piece
DebugVillageSectionsCustomPayload
DebugWorldgenAttemptCustomPayload

Login

LoginCompressionS2CPacket
LoginDisconnectS2CPacket
LoginHelloS2CPacket
LoginQueryRequestS2CPacket
LoginQueryRequestPayload
LoginSuccessS2CPacket
UnknownLoginQueryRequestPayload

Play

AdvancementUpdateS2CPacket
BlockBreakingProgressS2CPacket
BlockEntityUpdateS2CPacket
BlockEventS2CPacket
BlockUpdateS2CPacket
BossBarS2CPacket
- Action
- AddAction
- Consumer
- Type
- UpdateNameAction
- UpdateProgressAction
- UpdatePropertiesAction
- UpdateStyleAction
BundleDelimiterS2CPacket
BundleS2CPacket
ChatMessageS2CPacket
ChatSuggestionsS2CPacket
- Action
ChunkBiomeDataS2CPacket
- Serialized
ChunkDataS2CPacket
- BlockEntityData
- BlockEntityVisitor
ChunkDeltaUpdateS2CPacket
ChunkLoadDistanceS2CPacket
ChunkRenderDistanceCenterS2CPacket
ChunkSentS2CPacket
ClearTitleS2CPacket
CloseScreenS2CPacket
CommandSuggestionsS2CPacket
- Suggestion
CommandTreeS2CPacket
- ArgumentNode
- CommandNodeData
- CommandTree
- LiteralNode
- SuggestableNode
CommonPlayerSpawnInfo
CooldownUpdateS2CPacket
CraftFailedResponseS2CPacket
DamageTiltS2CPacket
DeathMessageS2CPacket
DebugSampleS2CPacket
DifficultyS2CPacket
EndCombatS2CPacket
EnterCombatS2CPacket
EnterReconfigurationS2CPacket
EntitiesDestroyS2CPacket
EntityAnimationS2CPacket
EntityAttachS2CPacket
EntityAttributesS2CPacket
- Entry
EntityDamageS2CPacket
EntityEquipmentUpdateS2CPacket
EntityPassengersSetS2CPacket
EntityPositionS2CPacket
EntityPositionSyncS2CPacket
EntityS2CPacket
- MoveRelative
- Rotate
- RotateAndMoveRelative
EntitySetHeadYawS2CPacket
EntitySpawnS2CPacket
EntityStatusEffectS2CPacket
EntityStatusS2CPacket
EntityTrackerUpdateS2CPacket
EntityVelocityUpdateS2CPacket
ExperienceBarUpdateS2CPacket
ExperienceOrbSpawnS2CPacket
ExplosionS2CPacket
GameJoinS2CPacket
GameMessageS2CPacket
GameStateChangeS2CPacket
- Reason
HealthUpdateS2CPacket
InventoryS2CPacket
ItemPickupAnimationS2CPacket
LightUpdateS2CPacket
LookAtS2CPacket
MapUpdateS2CPacket
MoveMinecartAlongTrackS2CPacket
NbtQueryResponseS2CPacket
OpenHorseScreenS2CPacket
OpenScreenS2CPacket
OpenWrittenBookS2CPacket
OverlayMessageS2CPacket
ParticleS2CPacket
PlayerAbilitiesS2CPacket
PlayerActionResponseS2CPacket
PlayerListHeaderS2CPacket
PlayerListS2CPacket
- Action
- Entry
- Serialized
PlayerPositionLookS2CPacket
PlayerRemoveS2CPacket
PlayerRespawnS2CPacket
PlayerRotationS2CPacket
PlayerSpawnPositionS2CPacket
PlaySoundFromEntityS2CPacket
PlaySoundS2CPacket
ProfilelessChatMessageS2CPacket
ProjectilePowerS2CPacket
RecipeBookAddS2CPacket
- Entry
RecipeBookRemoveS2CPacket
RecipeBookSettingsS2CPacket
RemoveEntityStatusEffectS2CPacket
RemoveMessageS2CPacket
ScoreboardDisplayS2CPacket
ScoreboardObjectiveUpdateS2CPacket
ScoreboardScoreResetS2CPacket
ScoreboardScoreUpdateS2CPacket
ScreenHandlerPropertyUpdateS2CPacket
ScreenHandlerSlotUpdateS2CPacket
SelectAdvancementTabS2CPacket
ServerMetadataS2CPacket
SetCameraEntityS2CPacket
SetCursorItemS2CPacket
SetPlayerInventoryS2CPacket
SetTradeOffersS2CPacket
SignEditorOpenS2CPacket
SimulationDistanceS2CPacket
StartChunkSendS2CPacket
StatisticsS2CPacket
StopSoundS2CPacket
SubtitleS2CPacket
SynchronizeRecipesS2CPacket
TeamS2CPacket
- Operation
- SerializableTeam
TickStepS2CPacket
TitleFadeS2CPacket
TitleS2CPacket
UnloadChunkS2CPacket
UpdateSelectedSlotS2CPacket
UpdateTickRateS2CPacket
VehicleMoveS2CPacket
WorldBorderCenterChangedS2CPacket
WorldBorderInitializeS2CPacket
WorldBorderInterpolateSizeS2CPacket
WorldBorderSizeChangedS2CPacket
WorldBorderWarningBlocksChangedS2CPacket
WorldBorderWarningTimeChangedS2CPacket
WorldEventS2CPacket
WorldTimeUpdateS2CPacket

Query

PingResultS2CPacket
QueryResponseS2CPacket

C2S (Client → Server)