How do you handle a 503 Service Unavailable error in a REST API?

Short answer: 503 indicates the server is temporarily unavailable (e.g., maintenance, overload). Best practices: Return a Retry-After header. Use monitoring/alerts to restore service quickly.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.