Multi-region read path with a sticky write region
Design a global SaaS API: users are worldwide, reads must be fast everywhere, but all durable writes currently go to one primary region (us-east). Show the request path for a logged-in read of a user profile that was updated 2 seconds ago in another region.
- ~20k RPS global reads
- Single primary for writes (for now)
- Profile payload ~5KB JSON
- Stale reads up to a few seconds are usually OK — except right after the user saves
Hint: Separate anonymous/cacheable from authenticated; call out session affinity or version tokens for read-your-writes.
Dojo II rules of engagement
Same loop as Dojo I — but interviewers will punish hand-waving on consistency, money, and races.
- Name the consistency requirement in one sentence before drawing boxes.
- Mark every arrow sync vs async.
- Own one ugly failure (partial outage, duplicate event, clock skew).
- Say what you would ship in v1 vs v2 under time pressure.
Sketch the multi-region read path — including what happens right after a write.