ScarMultiSession v2.1: Plug and Play Multiplayer Session System

Multiplayer development in Unreal Engine is historically time consuming and frustrating. Sessions fail to appear, level travel breaks, and backend configurations behave inconsistently. Developers often spend more time debugging than building their game.

ScarMultiSession is designed to remove that complexity. It is a plug and play multiplayer session system that handles the entire lifecycle: hosting, joining, lobby management, player synchronization, and match start logic. Built directly on Unreal Engine's Online Subsystem, the framework works across Steam, Epic Online Services (EOS), and LAN with zero backend specific code changes.

What is New in v2.1

• The Setup Doctor: Development builds automatically validate active Online Subsystems, cooked maps, and widget structures on Play to catch packaging and travel issues early.

• Unified Project Settings: Configure your maps, match parameters, and lobby widgets once from a single central settings panel.

• Single Value Sizing: Define match capacity with a single player count number. The session is sized dynamically and triggers travel when full.

Key Features

• Complete Host and Join: Gain full authority and control over multiplayer sessions.

• Smart Quick Join: Matchmaking logic automatically searches for active sessions and joins, or hosts a new session as a fallback if none exist.

• Replicated Lobby System: Includes player count tracking, countdown timers, and host start controls.

• Automatic Session Lifecycles: Handles creation, maintenance, and destruction internally.

• Multi Subsystem Support: Compatible with Steam, EOS, and LAN (NULL subsystem).

• Blueprint First Design: Built for Blueprints with optimized C++ underpinnings, requiring no C++ compile dependencies or manual delegate binding.

How It Works

Create your menu widget, call the setup function, and the multiplayer flow is ready.

• Sequence: Main Menu to Host or Join to Lobby to Game

All player tracking, session handling, and level transitions are managed internally by the plugin.

Use Cases

Suitable for a wide range of multiplayer projects:

• Cooperative games

• PvP experiences

• Party games

• Survival and sandbox multiplayer games

• Prototypes and game jam builds

Documentation

https://drive.google.com/file/d/18Re05Bvvsv4ZlHtdsrZAW4JDtphTIlYn/view?usp=sharing

Support

https://discord.gg/sAQ5FdMXJn