Fabric Packet Logger

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Fabric Packet Logger

By HelixCraftOwner

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Deep packet logging mod for Minecraft Fabric - captures all network traffic with full NBT/Component data

Mod Loaders
Minecraft
26.2

About

Description

Fabric Package Logger

Fabric API auf Modrinth

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)

Common

  • ClientOptionsC2SPacket
  • CommonPongC2SPacket
  • CookieResponseC2SPacket
  • CustomPayloadC2SPacket
  • KeepAliveC2SPacket
  • ResourcePackStatusC2SPacket
    • Status
    • SyncedClientOptions

Config

  • ReadyC2SPacket
  • SelectKnownPacksC2SPacket

Handshake

  • HandshakeC2SPacket
    • ConnectionIntent

Login

  • EnterConfigurationC2SPacket
  • LoginHelloC2SPacket
  • LoginKeyC2SPacket
  • LoginQueryResponseC2SPacket
    • LoginQueryResponsePayload
    • UnknownLoginQueryResponsePayload

Play

  • AcknowledgeChunksC2SPacket
  • AcknowledgeReconfigurationC2SPacket
  • AdvancementTabC2SPacket
    • Action
    • BoatPaddleStateC2SPacket
    • BookUpdateC2SPacket
    • BundleItemSelectedC2SPacket
    • ButtonClickC2SPacket
    • ChatCommandSignedC2SPacket
    • ChatMessageC2SPacket
    • ClickSlotC2SPacket
    • ClientCommandC2SPacket
      • Mode
    • ClientStatusC2SPacket
      • Mode
    • ClientTickEndC2SPacket
    • CloseHandledScreenC2SPacket
    • CommandExecutionC2SPacket
    • CraftRequestC2SPacket
    • CreativeInventoryActionC2SPacket
    • DebugSampleSubscriptionC2SPacket
    • HandSwingC2SPacket
    • JigsawGeneratingC2SPacket
    • MessageAcknowledgmentC2SPacket
    • PickItemFromBlockC2SPacket
    • PickItemFromEntityC2SPacket
    • PlayerActionC2SPacket
      • Action
    • PlayerInputC2SPacket
    • PlayerInteractBlockC2SPacket
    • PlayerInteractEntityC2SPacket
      • Handler
      • InteractAtHandler
      • InteractHandler
      • InteractType
      • InteractTypeHandler
    • PlayerInteractItemC2SPacket
    • PlayerLoadedC2SPacket
    • PlayerMoveC2SPacket
      • Full
      • LookAndOnGround
      • OnGroundOnly
      • PositionAndOnGround
    • PlayerSessionC2SPacket
    • QueryBlockNbtC2SPacket
    • QueryEntityNbtC2SPacket
    • RecipeBookDataC2SPacket
    • RecipeCategoryOptionsC2SPacket
    • RenameItemC2SPacket
    • RequestCommandCompletionsC2SPacket
    • SelectMerchantTradeC2SPacket
    • SlotChangedStateC2SPacket
    • SpectatorTeleportC2SPacket
    • TeleportConfirmC2SPacket
    • UpdateBeaconC2SPacket
    • UpdateCommandBlockC2SPacket
    • UpdateCommandBlockMinecartC2SPacket
    • UpdateDifficultyC2SPacket
    • UpdateDifficultyLockC2SPacket
    • UpdateJigsawC2SPacket
    • UpdatePlayerAbilitiesC2SPacket
    • UpdateSelectedSlotC2SPacket
    • UpdateSignC2SPacket
    • UpdateStructureBlockC2SPacket
    • VehicleMoveC2SPacket

Query

  • QueryPingC2SPacket
  • QueryRequestC2SPacket

License

This project is licensed under the GNU General Public License v3.0.

Credits

  • Fabric API Team
  • Minecraft Modding Community