OpenAPI (Swagger): Use OpenAPI (formerly Swagger) for documenting your?

Short answer: RESTful APIs. It provides a standardized format that can be used for automatic generation of API documentation, which can be easily shared and integrated with tools like Swagger UI.

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.