What is content negotiation in REST, and how does it work?

Short answer: Content negotiation allows clients to specify desired response format. Uses HTTP headers: Accept: application/json → Request JSON. Accept: application/xml → Request XML. The server returns response in requested format (if supported). 👉 Example in ASP.NET Core: Add XML formatter with services.AddControllers() .AddXmlSerializerFormatters();

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

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.