What does the "404 Not Found" status code mean, and how can it be used for error handling?

Short answer: Indicates the requested resource does not exist. Use when resource ID is invalid or missing. Helps clients handle missing data gracefully. Example in ASP.NET Core: var user = db.Users.Find(id);

Example code

if(user == null) return NotFound(new { status=404, error="User not found" });

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.