# Interview — Reorganization & Rollback

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

A: A previously indexed block can be replaced, invalidating provisional transfers.

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

A: Track block hash and parent hash; rollback orphaned events, then ingest canonical blocks.

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

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