> ## Documentation Index > Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt > Use this file to discover all available pages before exploring further. # Join Lobby > Join a lobby. Allowed entity token types: title_player_account, title ## Error codes This operation may return the following PlayFab errors: | Error | Code | | --- | --- | | LobbyBadRequest | 13007 | | LobbyDoesNotExist | 13000 | | LobbyMemberCannotRejoin | 13004 | | LobbyNotJoinable | 13003 | | LobbyPlayerAlreadyJoined | 13002 | | LobbyPlayerMaxLobbyLimitExceeded | 13008 | | LobbyRateLimitExceeded | 13001 | ## OpenAPI ````yaml post /Lobby/JoinLobby openapi: 3.0.0 info: version: '260922' title: PlayFab Multiplayer API description: >- API methods for managing multiplayer servers. API methods for managing parties. The lobby service helps players group together to play multiplayer games. It is often used as a rendezvous point for players to share connection information. The TrueSkill service helps titles to estimate a player's skill based on their match results. The player skill values from this service are commonly used by a matchmaking service to provide players with balanced matches. termsOfService: https://playfab.com/terms/ contact: url: https://community.playfab.com/index.html license: name: Apache 2.0 url: https://github.com/PlayFab/API_Specs/blob/master/LICENSE servers: - url: https://{titleId}.playfabapi.com description: PlayFab title endpoint variables: titleId: default: your_title_id description: Your PlayFab title ID (hex). security: [] tags: - name: Lobby description: '' - name: Matchmaking description: Matchmaking APIs - name: Matchmaking Admin description: Matchmaking Admin APIs - name: MultiplayerServer description: Multiplayer Server APIs - name: PubSub description: PlayFab PubSub APIs - name: TrueSkill description: TrueSkill APIs - name: TrueSkill Admin description: TrueSkill Admin APIs paths: /Lobby/JoinLobby: post: tags: - Lobby summary: Join Lobby description: | Join a lobby. Allowed entity token types: title_player_account, title ## Error codes This operation may return the following PlayFab errors: | Error | Code | | --- | --- | | LobbyBadRequest | 13007 | | LobbyDoesNotExist | 13000 | | LobbyMemberCannotRejoin | 13004 | | LobbyNotJoinable | 13003 | | LobbyPlayerAlreadyJoined | 13002 | | LobbyPlayerMaxLobbyLimitExceeded | 13008 | | LobbyRateLimitExceeded | 13001 | operationId: JoinLobby requestBody: content: application/json: schema: $ref: '#/components/schemas/JoinLobbyRequest' description: Request to join a lobby. Only a client can join a lobby. responses: '200': $ref: '#/components/responses/JoinLobbyResult' '400': $ref: '#/components/responses/ApiErrorWrapper' security: - EntityToken: [] components: schemas: JoinLobbyRequest: description: Request to join a lobby. Only a client can join a lobby. type: object properties: ConnectionString: description: >- A field which indicates which lobby the user will be joining. This field is opaque to everyone except the Lobby service. type: string CustomTags: description: >- The optional custom tags associated with the request (e.g. build number, external trace identifiers, etc.). type: object MemberData: description: >- The private key-value pairs used by the member to communicate information to other members and the owner. Visible to all entities in the lobby. At most 30 key-value pairs may be stored here, keys are limited to 30 characters and values to 1000. The total size of all memberData values may not exceed 4096 bytes.Keys are case sensitive. type: object MemberEntity: allOf: - $ref: '#/components/schemas/EntityKey' description: The member entity who is joining the lobby. example: MemberEntity: Id: '1234' Type: title_player_account TypeString: title_player_account ConnectionString: connString MemberData: MyDataKey: MyDataKey value EntityKey: description: >- Combined entity type and ID structure which uniquely identifies a single entity. type: object properties: Id: description: Unique ID of the entity. type: string Type: description: >- Entity type. See https://learn.microsoft.com/gaming/playfab/features/data/entities/available-built-in-entity-types type: string required: - Id JoinLobbyResult: type: object properties: LobbyId: description: Successfully joined lobby's id. type: string required: - LobbyId ApiErrorWrapper: description: The basic wrapper around every failed API response type: object properties: code: description: Numerical HTTP code type: integer status: description: String HTTP code type: string error: description: Playfab error code type: string errorCode: description: Numerical PlayFab error code type: integer errorMessage: description: Description for the PlayFab errorCode type: string errorDetails: description: Detailed description of individual issues with the request object type: object required: - code - errorCode responses: JoinLobbyResult: description: '' content: application/json: schema: type: object properties: code: type: integer description: >- The Http status code. If X-ReportErrorAsSuccess header is set to true, this will report the actual http error code. status: type: string description: The Http status code as a string. data: $ref: '#/components/schemas/JoinLobbyResult' ApiErrorWrapper: description: This is the outer wrapper for all responses with errors content: application/json: schema: $ref: '#/components/schemas/ApiErrorWrapper' securitySchemes: EntityToken: type: apiKey in: header name: X-EntityToken description: >- This API requires an Entity Session Token, available from the Entity GetEntityToken method. ```` ## Related topics - [Join lobbies](/services/playfab/multiplayer/lobby/join-lobbies.md) - [Join Lobby](/api-reference/lobby/join-lobby.md) - [Join Lobby As Server](/services/playfab/api-references/rest/multiplayer/lobby/join-lobby-as-server.md) - [PFMultiplayerJoinLobby](/services/playfab/multiplayer/lobby/playfabmultiplayerreference-cpp/pflobby/functions/pfmultiplayerjoinlobby.md) - [PFMultiplayerCreateAndJoinLobby](/services/playfab/multiplayer/lobby/playfabmultiplayerreference-cpp/pflobby/functions/pfmultiplayercreateandjoinlobby.md)