Matrix's video calling and screen sharing feature 'MatrixRTC,' which is attracting attention as an alternative to Discord, has rollback processing and synchronization functions, making it possible to develop multiplayer games.

The VoIP team at instant messenger Element presented the latest information about MatrixRTC , the video calling and screen sharing feature of Matrix , the decentralized protocol used by Element, at the open source software event FOSDEM 2026 .

Exploring MatrixRTC: Real time communication in rooms
https://element.io/blog/exploring-matrixrtc-real-time-communication-in-rooms/

FOSDEM 2026 - MatrixRTC x Godot, a Battle Royale (Remix) - YouTube


Element's VoIP feature and Element Call development team is working on 'MatrixRTC' with the aim of building the foundation for incorporating large-scale, secure VoIP solutions into Matrix.

While Matrix has historically focused on durable, asynchronous messaging, real-time communication requires low latency, flexible connectivity, and non-durability, while maintaining the core principles of Matrix: decentralization, collaboration, and security.

Previously, Matrix clients only supported one-to-one peer-to-peer WebRTC calls, and Matrix rooms were primarily used for call-oriented control and for persisting transient state in the room history. However, as call scale and use cases expanded beyond simple audio and video, it became clear that the protocol itself needed to formally support real-time communications and be more resilient to accommodate diverse use cases beyond one-to-one calls.

MatrixRTC is an attempt to natively embed real-time applications into Matrix while meeting the practical requirements of decentralized, scalable, low-latency, and end-to-end encrypted data communication.

MatrixRTX introduces the concept of 'slots,' which allow room administrators to add real-time communication capabilities to rooms. Slots can be anything, from voice calls and video calls to 3D worlds and multiplayer games. By combining an application and an identifier that specifies the type of data participants will exchange, multiple parallel sessions can be enabled within the same room.

The new m.call VoIP method will cover basic voice and video calling, and third-party apps will be fully supported, allowing developers to build virtual simulations, multiplayer games, and more.

'Slots' are managed via state events, ensuring persistence, permissions, and moderation by room administrators. When a participant joins a slot, they send a membership event to connect and publish media via the WebRTC SFU of their choice. The LiveKit SFU is supported, with FullMesh WebRTC and WebSocker also under consideration.

As live demos, the 'FlappyBird'-style game ' Godot-MatrixRTC-FlappyRoyal ' and the multiplayer racing game ' Godot-MatrixRTC-Keyboard-Kart ' have been released. An animated GIF of playing Godot-MatrixRTC-FlappyRoyal looks like this.


Although the MatrixRTC SDK is provided in JavaScript, the widget architecture allows low-level Matrix processing to be implemented in other SDKs.