WindowsGSM.Schedule1

A WindowsGSM plugin for hosting Schedule I dedicated servers, powered by the community mod DedicatedServerMod (S1DS) by ifBars.

Schedule I has no official dedicated server. This plugin automates installing the base game via SteamCMD, then deploying MelonLoader (the mod-loading framework) and DedicatedServerMod on top of it, so the game runs as a real headless server instead of a normal client.

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Installation

1. Drop the Schedule1.cs folder into WindowsGSM's plugins folder.
2. In WindowsGSM, click Reload Plugins.
3. Add Server > select Schedule I Dedicated Server (S1DS).
4. When prompted, log in with a Steam account that owns Schedule I. Anonymous SteamCMD login will not work - this is a paid Early Access title with no free/anonymous server depot, unlike games such as Valheim that ship a separate free dedicated-server App ID.
5. Let Install run. On first install, the plugin automatically:
   • Downloads and extracts MelonLoader (Windows x64 build) into the game folder.
   • Downloads and extracts the matching DedicatedServerMod package (auto-detects IL2CPP vs Mono by checking for GameAssembly.dll).
6. Click Start. The very first launch will take noticeably longer than normal - MelonLoader has to generate IL2CPP interop assemblies once. Subsequent launches are fast.

IL2CPP is the correct target for current Schedule I releases. The plugin auto-detects this for you and will deploy the IL2CPP build of DedicatedServerMod - you shouldn't need to do anything about it, but if you ever see it behaving like it deployed the Mono build instead, something's wrong (e.g. GameAssembly.dll missing from the game folder for some reason). IL2CPP is what every current install should end up using.

Ports

• Server Port (default 38465) - UDP for gameplay, also used by S1DS's own TCP status-query endpoint.
• Query Port (default 27016) - Steam game server query port (steamGameServerQueryPort), only relevant if using SteamGameServer auth.

Forward both if you want players connecting from outside your LAN. See "Connecting from a client" below for why a Steam server browser / invite won't work here.

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Post-install configuration

After the first successful Start/Stop, two files get generated under serverfiles\UserData\:

• server_config.toml - the actual server config (name, ports, auth, gameplay, autosave, etc). This is the main file you'll want to review.
• permissions.toml - role hierarchy (default → support → moderator → administrator → operator) for players/admins using in-game or chat commands. Doesn't affect the local host console.

You don't need to touch MelonPreferences.cfg. Running through WindowsGSM already suppresses everything about MelonLoader's own console - it never pops up a window at all - so there's nothing to configure there.

Everything about how the server behaves (auth, mod verification, gameplay, etc.) is controlled through server_config.toml. You don't need to worry about command-line arguments or WindowsGSM's Additional Parameters field for any of this - it's all handled through the config file.

A few settings are controlled by WindowsGSM itself, not the config file: Server Name, Server Port, Server Query Port, Server Maxplayer, and Server GSLT in WindowsGSM's own Edit Server dialog get synced into server_config.toml automatically every time you click Start. Edit those five from WindowsGSM, not by hand-editing the config file - any manual edit to those specific lines in server_config.toml will get overwritten on the next Start.

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Steam authentication - read this before going further

This is the single most confusing part of running this server, so here's everything we figured out.

server_config.toml → [authentication] has an authProvider setting with three options:

Value	Behavior
None	No Steam auth at all. Players connect freely by IP. Good for local testing, not real deployments (no ownership/VAC verification).
SteamGameServer	Recommended for real hosting - the server registers itself with Steam as a game server to verify connecting players.
(GSLT-based)	Set steamGameServerLogOnAnonymous = false + a real steamGameServerToken instead of anonymous login.

Why SteamGameServer mode can fail to initialize: Schedule I doesn't ship as a true standalone dedicated-server binary - it's the actual client executable being repurposed, so anonymous game-server login doesn't always work reliably.

The fix: use a Game Server Login Token (GSLT) instead of anonymous login. A GSLT is a token scoped specifically to a game-server identity - this is what Valve built for exactly this situation, and it's the recommended, reliable way to authenticate.

1. Go to https://steamcommunity.com/dev/managegameservers logged in as the account that owns the game.
2. Enter App ID 3164500, generate a token.
3. Paste the token into WindowsGSM's Server GSLT field in the Edit Server dialog (not server_config.toml directly - see the note above).
4. Start the server - no Steam client needed running in the background.

Leaving Server GSLT blank keeps the server on anonymous login.

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Connecting from a client

This does not use Steam's normal P2P lobby/invite system - S1DS replaces it with direct IP:port connections. Players need MelonLoader and a matching S1DS client package:

1. A legitimate copy of Schedule I on Steam.
2. Download MelonLoader and install it in your own game folder - grab MelonLoader.x64.zip from the MelonLoader releases page and extract its contents directly into your Schedule I game folder (the one with Schedule I.exe in it). To find that folder: in Steam, right-click Schedule I > Properties > Installed Files > Browse.
3. Download the matching S1DS client package (Il2cpp_Client.zip or Mono-Client.zip - must match your server's build type; Il2cpp is the right one for current Schedule I releases) from the S1DedicatedServers releases page and extract its contents directly into the same game folder as above (the one with Schedule I.exe in it).
4. Launch the game normally through Steam.
5. Use the client mod's direct-connect option with your server's public IP and port (38465 by default).

If testing on the same machine/LAN as the server, launch the client before starting the dedicated server - Steam can block starting a client if the game-server process for the same account/app is already running; the reverse order works fine.

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Support

If this plugin saved you some time, Buy Me a Coffee.

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Credits

• WindowsGSM - the server management tool this plugin is built for
• DedicatedServerMod (S1DS) by ifBars
• MelonLoader by LavaGang
• Plugin author: Hotwire90

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MIT License - Copyright (c) 2026 Hotwire90. See LICENSE for full terms.