What is the statelessness principle in REST?

Short answer: Statelessness means each client request to the server must contain all the necessary information to process it (like authentication token, parameters, body).

Explain a bit more

The server does not store client session state. 👉 Example in ASP.NET Core Web API: [HttpGet("profile")] public IActionResult GetProfile([FromHeader] string token) if (string.IsNullOrEmpty(token)) return Unauthorized(); // Token is validated each time (stateless, no session memory) return Ok(new { Name = "John Doe", Email = "john@example.com" }); }

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.