Node.js project ideas for advanced developers

Systems problems: concurrency, reliability, scale. 2 Node.js projects at this level:

Collaborative whiteboardMultiple people draw on a shared canvas in real time, with undo and offline tolerance.Advanced6 to 8 weeksTypeScriptNode.js
Background job queue with retriesA job queue on Postgres with retries, backoff, scheduling and a small dashboard.Advanced5 to 6 weeksNode.jsSQLTypeScript

Generate one for my stack and time