Canvas Streaming

Canvas Streaming lets a participant publish any view — an HTML5 canvas element, a graphics layer, a composited scene — as a live video stream into the room. All other participants subscribe to it exactly like any other video stream. The canvas stream can also be recorded and is the foundation for the Annotation feature.

Common use cases include sharing dynamic data visualisations, rendering presentation slides frame-by-frame, overlaying graphics on a live feed, or running a whiteboard that other participants can watch as a video track.

Canvas Streaming must be enabled at room creation time. Add the canvas: true flag to the room settings object in your Create Room API payload:

{
  "settings": {
    "canvas": true
  }
}

Rooms created without this flag will not support canvas publish operations.

Who Can Initiate Canvas Streaming

Canvas Streaming requires access to an HTML5 <canvas> element to capture frames and encode them as a video stream. This means:

• Web SDK — Can both initiate and receive canvas streams. The canvas element lives in the browser DOM, so full publish + subscribe is supported.
• Android SDK, iOS SDK, React Native, Flutter, Cordova — Can receive and display a canvas stream published by a Web SDK participant. These platforms cannot initiate canvas streaming themselves.

Canvas Streaming methods, stream publication options, and subscriber event callbacks are documented in each SDK's In-Session Communication reference:

• Web SDK — Canvas Streaming
• Android SDK — Canvas Streaming
• iOS SDK — Canvas Streaming
• React Native SDK — Canvas Streaming
• Cordova / Ionic SDK — Canvas Streaming