Gameplay systems

Just like on the client, the server SDK provides systems — classes that expose a tick method, run on the server's own update loop. Use these for logic that should run continuously on the server, independent of any single RPC call: passive income, timers, periodic world state checks, and so on.

Declaring systems

A server-side system derives from ModSystemBase and overrides OnUpdate:

Minimal server system example

public class MySystem : ModSystemBase
{
    protected override void OnUpdate(UpdateTick tick)
    {
        // do something every server tick
    }
}

The UpdateTick passed to OnUpdate exposes deltaTime (seconds since the last tick) and time (seconds since server start).

important

Unlike client-side systems, server-side systems are not discovered automatically. Register each one explicitly in your mod's Init method:

protected override void Init()
{
    Services.RegisterSystem<MySystem>();
}

You can inject dependencies — such as EcsApi — through the constructor, same as any other service resolved from the dependency injection container.

A system with a dependency

public class PassiveIncomeSystem(EcsApi ecsApi) : ModSystemBase
{
    protected override void OnUpdate(UpdateTick tick)
    {
        ecsApi.Query<WalletComponent>((ref wallet) =>
        {
            wallet.Balance += 1;
        });
    }
}