0x02 S02PacketLoginSuccess

Confirms successful authentication. Contains the player's UUID and username. Transitions the connection state from LOGIN to PLAY.

Clientbound (Server → Client) · LOGIN · net/minecraft/network//S02PacketLoginSuccess.java
loginauthenticationplayer

Fields

FieldTypeDescription
uuidString (36 chars)Player's UUID in standard format (e.g. '123e4567-e89b-12d3-a456-426614174000')
usernameString (max 16)The player's confirmed username

Wire Encoding

FieldTypeNotes
UUIDStringUUID with dashes
UsernameStringPlayer's Minecraft username

MCP References

MCPNetHandlerLoginClient.handleLoginSuccess()

Handler Interface

HNDINetHandlerLoginClient

Notes

After receiving this, the client connection state transitions to PLAY. The client creates the EntityPlayerSP (local player entity) with the received UUID and username. Compression may be enabled next via S03PacketEnableCompression.

implementation Implementation Cases

SessionStealer (November 0.2)

Capture login success data (UUID, username) for session management.

Vanilla hook: EventReceivePacket
SessionInfo (November 0.2)

Capture login success data (UUID, username) for session management.

Vanilla hook: EventReceivePacket
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