OAuth 2.0:?

Short answer: The API Gateway can be integrated with OAuth 2.0 to authenticate incoming requests by verifying the OAuth token.

Example code

Check for a valid JWT token passed in the request header (Authorization: Bearer <token>).

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.