How does the two-phase commit protocol work in a distributed transaction context?

Short answer: The Two-Phase Commit (2PC) protocol is a mechanism to ensure that a distributed transaction is committed successfully across multiple services or databases. It involves two phases:

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

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.