Multiplayer Reference

This allows players to join online lobbies and synchronize gameplay across devices without needing to manage servers or networking.

Use the "Open game lobbies" action to let players join a game, and use conditions like "Lobby game has just started" to begin gameplay. Add the "Multiplayer object" behavior to game objects that should be synchronized, and assign or change their ownership using player numbers. Variables and game state (like scenes, scores, or timers) are automatically synced by the host, with options to change ownership or disable sync when needed. Common multiplayer logic —like handling joins/leaves, collisions, and host migration— is supported out-of-the-box for up to 8 players per game. Read more explanations about it.

Actions

Disable variable synchronization
Disable synchronization of the variable over the network. It will not be sent to other players anymore.

See parameters

Parameter 1: 🗄️ Any variable

End Lobby Game
End the lobby game. This will trigger the "Lobby game has just ended" condition.

Configure lobby game to end when host leaves
Configure the lobby game to end when the host leaves. This will trigger the "Lobby game has just ended" condition. (Default behavior is to migrate the host)

See parameters

Parameter 0 (❓ Yes or No): End lobby game when host leaves

Get message variable
Store the data of the specified message in a variable. Use with the condition 'Message has been received' to know when the message has been properly processed by the host.

See parameters

Parameter 0 (string): Message name
Parameter 1: 🗄️ Any variable

Leave Game Lobby
Leave the current game lobby. This will trigger the "Player has left" condition on the other players, and the "Lobby game has ended" condition on the player leaving.

Open Game Lobbies
Open the game lobbies window, where players can join lobbies or see the one they are in.

See parameters

Join the next available lobby
Join the next available lobby. The player will join the game instantly if this is possible.

See parameters

Parameter 1 (❓ Yes or No): Display loader while searching for a lobby.
Parameter 2 (❓ Yes or No): Display game lobbies if no lobby can be joined directly.

Join a specific lobby by its ID
Join a specific lobby. The player will join the game instantly if this is possible.

See parameters

Parameter 1 (string): Lobby ID
Parameter 2 (❓ Yes or No): Display loader while joining a lobby.
Parameter 3 (❓ Yes or No): Display game lobbies if unable to join a specific one.

Remove ownership of variable
Remove the ownership of the variable. It will still be synchronized to other players, but the host owns it.

See parameters

Parameter 1 (🗄️ Any variable): Variable Only root variables can change ownership. Arrays and structures children are synchronized with their parent.

Send custom message to other players
Send a custom message to other players in the lobby, with an automatic retry system if it hasn't been received. Use with the condition 'Message has been received' to know when the message has been properly processed by the host.

See parameters

Parameter 0 (string): Message name
Parameter 1 (string): Message content

Send custom message to other players with a variable
Send a custom message to other players in the lobby containing a variable, with an automatic retry system if it hasn't been received. Use with the condition 'Message has been received' to know when the message has been properly processed by the host.

See parameters

Parameter 0 (string): Message name
Parameter 1: 🗄️ Any variable

Objects synchronization rate
Change objects synchronization rate (between 1 and 60, default is 30 times per second).

See parameters

Parameter 0: 🟰 Operator
Parameter 1 (🔢 Number): Sync rate

Player variable ownership
Change the player owning the variable.

See parameters

Parameter 1 (🗄️ Any variable): Variable Only root variables can change ownership. Arrays and structures children are synchronized with their parent.
Parameter 2: 🟰 Operator
Parameter 3 (🔢 Number): Player number

Allow players to close the lobbies window
Allow players to close the lobbies window. Allowed by default.

See parameters

Parameter 1 (❓ Yes or No): Show close button

Take ownership of variable
Take the ownership of the variable. It will then be synchronized to other players, with the current player as the owner.

See parameters

Parameter 1 (🗄️ Any variable): Variable Only root variables can change ownership. Arrays and structures children are synchronized with their parent.

Conditions

Current player number in lobby
Compare the current player number in the lobby (1, 2, ...).

See parameters

Parameter 0: 🟰 Relational operator
Parameter 1 (🔢 Number): Value to compare

Any player has joined
Check if any player has joined the lobby.

Any player has left
Check if any player has left the lobby game.

Lobby game has just ended
Check if the lobby game has just ended.

Lobby game has just started
Check if the lobby game has just started.

Custom message has been received from another player
Check if a custom message has been received from another player. Will be true only for one frame.

See parameters

Parameter 0 (string): Message name

Player has joined
Check if the player has joined the lobby.

See parameters

Parameter 0 (🔢 Number): Player number

Player has left
Check if the player has left the lobby game.

See parameters

Parameter 0 (🔢 Number): Player number

Lobbies window is open
Check if the lobbies window is open.

See parameters

Lobby game is running
Check if the lobby game is running.

Host is migrating
Check if the host is migrating, in order to adapt the game state (like pausing the game).

Player is connected
Check if the specified player is connected to the lobby.

See parameters

Parameter 0 (🔢 Number): The position of the player in the lobby (1, 2, ...)

Player is host
Check if the player is the host. (Player 1 is the host)

Is searching for a lobby to join
Is searching for a lobby to join.

See parameters

Objects synchronization rate
Compare objects synchronization rate (between 1 and 60, default is 30 times per second).

See parameters

Parameter 0: 🟰 Relational operator
Parameter 1 (🔢 Number): Sync rate

Player variable ownership
Compare the player owning the variable.

See parameters

Parameter 1 (🗄️ Any variable): Variable Only root variables can change ownership. Arrays and structures children are synchronized with their parent.
Parameter 2: 🟰 Relational operator
Parameter 3 (🔢 Number): Player number

Number of players in lobby
Compare the number of players in the lobby.

See parameters

Parameter 0: 🟰 Relational operator
Parameter 1 (🔢 Number): Value to compare

Quick join failed to join a lobby
Quick join failed to join a lobby.

See parameters

Expressions

Expression	Description
`Multiplayer::CurrentLobbyID()`	Returns current lobby ID.
`Multiplayer::CurrentPlayerNumber()`	Return the current player number in the lobby (1, 2, ...).
`Multiplayer::CurrentPlayerPing()`	Get the ping of the current player in the lobby.
`Multiplayer::CurrentPlayerUsername()`	Get the username of the current player in the lobby.
`Multiplayer::LastJoinedPlayerNumber()`	Returns the player number of the player that has just joined the lobby.
`Multiplayer::LastLeftPlayerNumber()`	Returns the player number of the player that has just left the lobby.
`Multiplayer::MessageData(string)`	Returns the data received when the specified message was received from another player.
	string	Message name
`Multiplayer::MessageSender(string)`	Returns the player number of the sender of the specified message.
	string	Message name
`Multiplayer::ObjectsSynchronizationRate()`	Return objects synchronization rate (between 1 and 60, default is 30 times per second).
`Multiplayer::PlayerPing(number)`	Get the ping of the player in the lobby.
	🔢 Number	The position of the player in the lobby (1, 2, ...)
`Multiplayer::PlayerUsername(number)`	Get the username of the player in the lobby.
	🔢 Number	The position of the player in the lobby (1, 2, ...)
`Multiplayer::PlayerVariableOwnership(variable)`	Return the player owning the variable.
	🗄️ Any variable	Variable Only root variables can change ownership. Arrays and structures children are synchronized with their parent.
`Multiplayer::PlayersInLobbyCount()`	Return the number of players in the lobby.
`Multiplayer::QuickJoinFailureReason()`	Returns the reason why the Quick join action failed. It can either be 'FULL' if all lobbies were occupied, 'NOT_ENOUGH_PLAYERS' if the lobby's configuration requires more than 1 player to start the game and no other players were available. It can also take the value 'UNKNOWN'.

Multiplayer object

Allow the object to be synchronized with other players in the lobby.

Behavior actions

Enable (or disable) the synchronization of a behavior
Enable or disable the synchronization of a behavior over the network. If disabled, the behavior's current state will not be sent to other players anymore.

See parameters

Parameter 0: 👾 Object
Parameter 1 (🧩 Behavior): Multiplayer behavior
Parameter 2 (🧩 Behavior): Object behavior
Parameter 3 (❓ Yes or No): Enable synchronization

Remove object ownership
Remove the ownership of the object from the player. It will still be synchronized to other players, but the host owns it.

See parameters

Parameter 0: 👾 Object
Parameter 1: 🧩 Behavior

Player object ownership
Change the player owning the object.

See parameters

Parameter 0: 👾 Object
Parameter 1: 🧩 Behavior
Parameter 2: 🟰 Operator
Parameter 3 (🔢 Number): Player number

Take ownership of object
Take the ownership of the object. It will then be synchronized to other players, with the current player as the owner.

See parameters

Parameter 0: 👾 Object
Parameter 1: 🧩 Behavior

Behavior conditions

Is object owned by current player
Check if the object is owned by the current player, as a player or the host.

See parameters

Parameter 0: 👾 Object
Parameter 1: 🧩 Behavior

Player object ownership
Compare the player owning the object.

See parameters

Parameter 0: 👾 Object
Parameter 1: 🧩 Behavior
Parameter 2: 🟰 Relational operator
Parameter 3 (🔢 Number): Player number

Behavior expressions

Expression	Description
`Object.MultiplayerObject::PlayerObjectOwnership()`	Return the player owning the object.

The Multiplayer extension is always installed in all GDevelop projects: there is no need to add it from the Project Manager.

This page is an auto-generated reference page about the Multiplayer feature of GDevelop, the open-source, cross-platform game engine designed for everyone. Learn more about all GDevelop features here.