An interactive whiteboard in a virtual classroom is a multi-user canvas where the instructor and learners can draw, type, insert shapes, and annotate images in real time, with every stroke visible to all participants within tens of milliseconds. The underlying technology is typically a conflict-free replicated data type (CRDT) or an operational-transformation engine that merges concurrent edits without conflicts, running over WebSocket or a WebRTC data channel. Unlike screen sharing, the whiteboard produces structured vector data rather than a video stream, so it remains sharp at any zoom level and its final state can be exported as a PDF or image for the class record. Pedagogically the shared canvas enables spatial reasoning — diagramming a process, labeling an anatomy chart, working through an equation step by step — that chat and audio alone cannot support. Permission control is important: in a large class the instructor may restrict drawing rights to avoid chaos, granting write access to individual learners for specific tasks. Integration with the session recording is a practical consideration: the whiteboard state at each moment should be reflected in the video recording so that an async viewer sees what the live participants saw. The main trade-off is latency versus consistency: optimistic local rendering with server reconciliation feels fast but can cause brief visual glitches when two users draw in the same region simultaneously.
