Technical Architecture of Rec Room's Multiplayer Scripting System: Solving Synchronization Challenges

Circuits is Rec Room's technology for programming rooms: a multiplayer-synchronized realtime scripting system that lets players build interactive experiences together.

Creating Circuits is one of the top honors of my career. I'd like to share how we solved core networking challenges, for anyone working on similar problems.

For shapes, the unit of synchronization was a game object, but for Circuits we needed something more sophisticated - we needed to synchronize not just objects but the execution of logic across multiple clients.

The key insight was that we needed deterministic execution - every client had to arrive at the same state given the same inputs, regardless of network conditions.

We ended up with a hybrid approach: some operations were fully deterministic and executed locally, while others required server arbitration to maintain consistency across all players.