ILobbyMatchmakingService – Steam Web API Documentation

Creates a lobby and sets its related lobby data

https://partner.steam-api.com/ILobbyMatchmakingService/CreateLobby/v1/

Name	Value	Type	Required	Description
key	click to set	string	Yes	Access key
appid		uint32	Yes
max_members		int32	Yes
lobby_type		int32	Yes
lobby_name		string	Yes
steamid_invited_members		uint64	Yes
lobby_metadata		{message}	Yes

Returns lobby data and member list

https://partner.steam-api.com/ILobbyMatchmakingService/GetLobbyData/v1/

Name	Value	Type	Required	Description
key	click to set	string	Yes	Access key
appid		uint32	Yes
steamid_lobby		uint64	Yes

Removes a user from a lobby

https://partner.steam-api.com/ILobbyMatchmakingService/RemoveUserFromLobby/v1/

Name	Value	Type	Required	Description
key	click to set	string	Yes	Access key
appid		uint32	Yes
steamid_lobby		uint64	Yes
steamid_to_remove		uint64	Yes