What tools can be used for API documentation?

Short answer: Swagger/OpenAPI → Standard for REST API design and documentation. Postman → Can generate collections and documentation automatically. Redoc → Static documentation from OpenAPI specs. RAML → RESTful API Modeling Language. Stoplight, Apiary, Docusaurus → Modern documentation and mocking platforms.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

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.