First Multiplayer Game

Build the smallest complete RedEngine game: one arena, one game mode, one controller, and one playable character.

Execution model for this tutorial

• Authority — State Authority admits the player, spawns the controller/character, and changes gameplay state.
• Prediction — Input Authority may simulate movement and explicitly prediction-safe abilities.
• Replicated — controller ownership, character pose, attributes, effects, and match state.
• Local only — particles, UI, audio, camera, and render interpolation.

1. Create the project settings

Create Assets/Resources/EngineSettings.asset. Assign a NetworkRunner prefab, the gameplay scene, the server map if it differs, and the default port. Do not add Fusion's default scene manager; RedEngine supplies its own through GameInstance.

2. Add the game mode

Create a prefab with NetworkObject and a GameModeBase subclass. Assign its player-controller and default-character prefabs, then place exactly one instance in the gameplay scene.

public sealed class ArenaGameMode : GameModeBase
{
    protected override bool ReadyToStartMatch() =>
        World.PlayerControllers.Any();
}

3. Prepare the player

Create a PlayerController prefab and a Character prefab. Both must be spawnable Fusion network prefabs. Start by duplicating their showcase counterparts, then remove optional systems after the baseline works.

4. Connect input

Create InputSettings and an InputContext. Map an Input System action to a network channel, then map the channel and trigger to an [InputHandler] method on the controller or possessed character.

[InputHandler]
public void Move(Vector2 value) => characterController.SetMovementInput(value);

5. Add a replicated objective

Start with one authoritative action: entering a trigger applies damage, or interacting with a pickup adds an item. Test it with one peer, then two. Use Fusion network state and TickTimer for gameplay; do not use coroutines or wall-clock delays for replicated outcomes.

6. Verify the complete loop

• the server finds one GameModeBase;
• joining creates one controller and one character;
• each peer controls only its input-authority character;
• leaving removes the controller;
• restarting the map creates a fresh World and world subsystems.

For the longer inspector-by-inspector version, see Your First Multiplayer Scene.

Next: choose a small task from Recipes, then use Where to Go Next to enter the Manual.