Identity Federation: For third-party integrations, use identity federation with OAuth?

Short answer: or OpenID Connect to enable third-party services to authenticate users.

Example code

A user logs in through OAuth, receives a JWT token, and then accesses different microservices (e.g., Order Service, Payment Service) by including the token in HTTP headers.

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.