Online Whiteboard — Notes

Functional

• Infinite canvas with shapes, text, images, sticky notes.
• Multi-user with cursors.
• Templates, voting, timer, embeds.
• Export, comments.

Non-functional

• Op echo < 200 ms.
• Many concurrent editors per board.
• Large boards (10k+ elements) must scroll smoothly.

Trade-offs

• Per-board owner simplifies; failover requires replay.
• Vector elements stream as ops; raster assets via CDN.
• Excalidraw is open-source and CRDT-friendly; Miro is closed.

Refs

• Excalidraw architecture (open source).
• Miro engineering posts.
• ByteByteGo "Design collaborative whiteboard".