# Interview — Transactional Outbox & Deduplication

**Q: What is the main failure mode?**

A: Writing DB then publishing Kafka can lose events on crash; delivery can be repeated.

**Q: How do you mitigate it?**

A: Persist domain update plus outbox record atomically; retry publication and deduplicate by event ID.

**Q: Is this demo production-ready?**

A: No. It illustrates an invariant in memory; production requires durable storage, retries, monitoring, security, and integration tests.