Client mods implement IClientMod or inherit ClientModBase / ClientMelonModBase. Use S1DS.Client for access to dedicated-client systems.

Lifecycle Hooks

• OnClientInitialize()
• OnClientShutdown()
• OnConnectedToServer()
• OnDisconnectedFromServer()
• OnClientPlayerReady()
• OnCustomMessage(string messageType, byte[] data)

Use OnClientPlayerReady() for logic that depends on UI and messaging already being initialized.

Client Systems

Available in CLIENT builds via S1DS.Client:

• ClientCore
• Connection
• UI
• Console
• Quests
• Loopback
• Transport
• IsConnected
• IsInitialized

Example:

public override void OnClientPlayerReady()
{
    if (!S1DS.Client.IsConnected)
    {
        return;
    }

    // Messaging and UI are safe to use here.
}

Registration

Auto-discovery

Any MelonMod that implements IClientMod is discovered automatically. This includes:

• SideAwareMelonModBase
• ClientMelonModBase
• direct IClientMod implementations

Manual registration

internal sealed class MyClientHandler : ClientModBase
{
    public override void OnClientInitialize()
    {
    }
}

public sealed class MyMod : MelonMod
{
    public override void OnInitializeMelon()
    {
#if CLIENT
        ModManager.RegisterClientMod(new MyClientHandler());
#endif
    }
}

Registration ensures client message forwarding is wired so OnCustomMessage can be delivered.

Do not manually register a MelonMod that already implements IClientMod or inherits ClientMelonModBase / SideAwareMelonModBase.

Declaring Client Mod Identity

If your client mod may be checked by a dedicated server, declare its stable identity at the assembly level:

using DedicatedServerMod.API;

[assembly: S1DSClientModIdentity("ghost.marketterminal", "2.1.0")]

This is strongly recommended for:

• client companions paired with a server mod
• client-only mods that server owners may want to identify by stable mod ID

When the mod is paired, the modId should match the server-side S1DSClientCompanionAttribute.

See Companion Mods and Verification Metadata for the full paired-mod workflow and strict-mode notes.

For exact signatures and XML documentation, use the generated API reference alongside this guide.