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 & details

• Parameter 1: 🗄️ Any variable

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::DisableVariableSynchronization.

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

See parameters & details

There are no parameters to set for this action.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::EndLobbyGame.

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 & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::EndLobbyWhenHostLeaves.

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 & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::GetMessageVariable.

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.

See parameters & details

There are no parameters to set for this action.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::LeaveGameLobby.

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

See parameters & details

There are no parameters to set for this action.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::OpenGameLobbies.

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

See parameters & details

• 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.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::QuickJoinLobby.

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

See parameters & details

• 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.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::QuickJoinWithLobbyID.

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 & details

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

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::RemoveVariableOwnership.

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 & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::SendMessage.

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 & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::SendVariableMessage.

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

See parameters & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::SetObjectsSynchronizationRate.

Player variable ownership
Change the player owning the variable.

See parameters & details

• 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

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::SetPlayerVariableOwnership.

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

See parameters & details

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

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::ShowLobbiesWindowCloseAction.

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 & details

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

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::TakeVariableOwnership.

Conditions

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

See parameters & details

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

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::CurrentPlayerNumber.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasAnyPlayerJoined.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasAnyPlayerLeft.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasLobbyGameJustEnded.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasLobbyGameJustStarted.

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 & details

• Parameter 0 (string): Message name

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasMessageBeenReceived.

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

See parameters & details

• Parameter 0 (🔢 Number): Player number

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasPlayerJoined.

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

See parameters & details

• Parameter 0 (🔢 Number): Player number

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::HasPlayerLeft.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsLobbiesWindowOpen.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsLobbyGameRunning.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsMigratingHost.

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

See parameters & details

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

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsPlayerConnected.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsPlayerHost.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::IsSearchingForLobbyToJoin.

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

See parameters & details

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

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::ObjectsSynchronizationRate.

Player variable ownership
Compare the player owning the variable.

See parameters & details

• 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

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::PlayerVariableOwnership.

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

See parameters & details

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

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::PlayersInLobbyCount.

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

See parameters & details

There are no parameters to set for this condition.

Technical note: parameter 0 is an internal parameter handled by GDevelop.

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::QuickJoinJustFailed.

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 & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::EnableBehaviorSynchronization.

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 & details

• Parameter 0: 👾 Object
• Parameter 1: 🧩 Behavior

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::RemoveObjectOwnership.

Player object ownership
Change the player owning the object.

See parameters & details

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

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::SetPlayerObjectOwnership.

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 & details

• Parameter 0: 👾 Object
• Parameter 1: 🧩 Behavior

Technical note: this action internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::TakeObjectOwnership.

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 & details

• Parameter 0: 👾 Object
• Parameter 1: 🧩 Behavior

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::IsObjectOwnedByCurrentPlayer.

Player object ownership
Compare the player owning the object.

See parameters & details

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

Technical note: this condition internal type (in GDevelop JSON) is Multiplayer::MultiplayerObjectBehavior::PlayerObjectOwnership.

Behavior expressions

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

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

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