Steam lobbies and multiplayer in Godot
2 min read
By Eduardo Orellana ·
To put a Godot game online through Steam: create a lobby with Steam.createLobby(type, max_members) and wait for lobby_created; let friends join through the overlay with Steam.activateGameOverlayInviteDialog(lobby_id) and handle join_requested; find public lobbies with Steam.requestLobbyList() and lobby_match_list; then run Godot's high-level multiplayer over Steam with GodotSteam's SteamMultiplayerPeer. Players need no port forwarding, and Steam relays the traffic.
Steam solves the hardest part of indie multiplayer: finding each other
Most indie multiplayer games are played with friends. Steam already knows who your friends are, lets them click Join Game, and relays the traffic so nobody opens a port. GodotSteam exposes all of it to GDScript.
Create and join a lobby
A lobby is Steam's meeting room: up to 250 members, private, friends-only, public or invisible.
func host() -> void:
Steam.lobby_created.connect(_on_lobby_created)
Steam.createLobby(Steam.LOBBY_TYPE_FRIENDS_ONLY, 4)
func _on_lobby_created(result: int, lobby_id: int) -> void:
if result == Steam.RESULT_OK:
Steam.setLobbyData(lobby_id, 'name', 'My lobby')
Steam.activateGameOverlayInviteDialog(lobby_id)
func _ready() -> void:
Steam.join_requested.connect(func(lobby_id: int, _friend: int) -> void: Steam.joinLobby(lobby_id))
Steam.lobby_joined.connect(_on_lobby_joined)Join Game, invites and lists
- Invites: activateGameOverlayInviteDialog() opens Steam's friend picker. It may not work when the game was not launched from Steam.
- Join Game from a friend's profile fires join_requested if the game is running; if it is not, Steam launches it with +connect_lobby <lobby id> on the command line.
- Public lobbies: add filters, call requestLobbyList(), read results in lobby_match_list (up to 50).
- Closing a lobby: setLobbyJoinable(false) once the match starts.
Carrying the game: SteamMultiplayerPeer
Once everyone is in the lobby, GodotSteam's SteamMultiplayerPeer lets Godot's normal high-level multiplayer (MultiplayerSpawner, MultiplayerSynchronizer, RPCs) run over Steam's networking: create a host peer on the lobby owner and client peers on the others, then assign it to multiplayer.multiplayer_peer. Your game code stays standard Godot.
Where Flockbay fits
In Flockbay, you can test multiplayer with a friend through join-code rooms while you build, free on every account. For the shipped game on Steam, Flockbay's AI writes GodotSteam into it as an ordinary autoload you own: the lobby, the overlay invite, Join Game and SteamMultiplayerPeer, standing down while a Flockbay room is the peer. Nothing of Flockbay's ships in your game.
Questions
- Do players need to port forward for Steam multiplayer in Godot?
- No. Steam's networking relays the connection through SteamMultiplayerPeer.
- How many players can a Steam lobby hold?
- Up to 250, according to GodotSteam's lobby documentation.