🖧 ATLYSS Dedicated Server Plugin

Originally made by FleeTime.

This BepInEx plugin adds headless dedicated server support to ATLYSS, enabling you to run the game in a terminal as a dedicated server — no graphics or UI needed.

⚠️ This is for hosting servers only. It will disable itself when the game is being launched normally.

✅ Mod Compatibility

• Fully compatible with other BepInEx mods that modify or enhance hosting behavior.
  This includes:
  • Chat formatting mods (e.g., colored messages)
  • Uncapped party size or connection limit mods
  • Custom stat or balance changes
  • Lobby tweak plugins

As long as the mod loads under BepInEx and applies during host/server initialization, it will work seamlessly with this dedicated server plugin.

🔍 Known Issues

• Connecting to the dedicated server using the same Steam account is not possible.
  • While you may be able to launch a new game instance in parallel with the dedicated server, it is not possible to connect to it using the same account as the one hosting the dedicated server.
  • As such, it's best to host the dedicated server using a separate Steam account with a copy of ATLYSS on it.

✅ Requirements

• BepInEx 5.x
• ATLYSS 112025.a4
• Must launch the game with the following arguments:

-batchmode -nographics -server

🛠️ Launch Syntax

ATLYSS.exe -batchmode -nographics -server [options...]

You must include at least-server before your own custom arguments for the mod to activate.

Specifying -batchmode -nographics is optional, but desirable to enable proper headless support.

The mod also generates start_dedicated_server.cmd on Windows and start_dedicated_server.sh on Linux that do it for you, however you might need to have the Steam client active for it to work correctly.

🔧 Available Arguments

⚠️ The priority of server type argument is -public, -private, then -friends in that order.
⚠️ The priority of server tag argument is -pve, -pvp, -social, then -rp in that order.
⚠️ If -hostsave is not specified, the server will default to using save slot 0.
⚠️ If there is no valid character in the given slot, a new random one will be created in it.

📦 Example Usages

Start a public PvE server with 16 players:

ATLYSS.exe -batchmode -nographics -server -name "MyServer" -motd "Welcome!" -maxplayers 16 -public -pve

Start a private PvP server with a password:

ATLYSS.exe -batchmode -nographics -server -name "Private Warzone" -password "hunter2" -maxplayers 10 -private -pvp

Start a friends-only social server:

ATLYSS.exe -batchmode -nographics -server -name "CozyHub" -motd "Grab tea and chill." -friends -social

Start a public PvE server with 64 players that restarts every 36 hours when the server is less than 25% full:

ATLYSS.exe -batchmode -nographics -server -name "Poontastic" -motd "Welcome!" -maxplayers 64 -public -pve -autorestart -autorestartin 36h -autorestartthreshold 25

🧠 Behavior Notes

• The host player is fully hidden from view.
• Console input works for typing commands directly
• Server can be force restarted with /restart, and force shutdown with /shutdown in the console window
• Server shutdowns and restarts (including the automatic restart) can be cancelled with /cancelrt or /cancelsd in the console window
• In-game chat is mirrored to the terminal (color tags handled)
• Audio is disabled via AudioListener.volume = 0
• Server config and startup logs are shown in the console

🧪 Troubleshooting

• ❌ Nothing happens? Make sure you're running with -batchmode -nographics -server
• ❌ Can't see the terminal? Check if console logging is enabled in BepInEx/config/BepInEx.cfg, or launch it through a CMD / bash shell

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[0.1.0] - 2025-Dec-23

Added

• Added a configuration file under BepInEx/config/FleesDedicatedServer.cfg as an additional option to specify dedicated server settings
• Added an option to schedule a server restart after a specified amount of time
  • The automatic restart can be configured to go through only when the server player count drops below a certain percentage of the maximum player count
  • The time interval is specified in the [XXd][XXh][XXm][XXs] format, such as 4h for 4 hours, 1d6h30m for 1 day, 6 hours and 30 minutes, etc.
  • The minimum time interval is 30 minutes
• Added /restart to the server console - this will restart the server after 20 seconds have elapsed
• Added /cancelrt - this command and /cancelsd will cancel a pending server shutdown or restart
• The mod will now generate start_dedicated_server.cmd on Windows and start_dedicated_server.sh on Linux with Proton
  • These scripts can be used to launch a dedicated server directly instead of having to specify launch options through Steam
  • You will need to first launch the game normally using this mod for those scripts to appear or be updated
• The mod will now generate steam_appid.txt to allow to boot the game without going through the Steam Client

Changed

• In-game audio is now muted while running with -batchmode -nographics
• The host player is now hidden from view instead of being teleported in an off-screen area

[0.0.7] - 2025-Nov-26

Version bump without significant changes

[0.0.6] - 2025-Apr-09

Fixed

• Updated mod code to work with the new update of ATLYSS.
• Cleaned up console output.

[0.0.5] - 2025-Apr-09

Fixed

• Removed deprecated dependency from mod (thanks for the heads up Marioalexsan).

[0.0.4] - 2025-Apr-09

Fixed

• Updated mod code to work with the new update of ATLYSS.

[0.0.3] - 2025-Apr-09

** Undocumented update **

[0.0.2] - 2025-Apr-09

Added

• -hostsave argument to specify which save slot the server host character uses (range: 0–6).
  • If not provided or out of range, defaults to save slot 0.
  • Warning logged if an invalid slot is given.

Changed

• You must have a valid character in the selected save slot to start the server.

[0.0.1] - 2025-Apr-09

Initial mod release