What is the cacheability principle in REST?

Short answer: Responses from the server should indicate whether they are cacheable or not, to improve performance and scalability. Clients and intermediaries can reuse cached responses. 👉 Example in ASP.NET Core: [HttpGet("products")] [ResponseCache(Duration = 60)] // Cache for 60 seconds public IActionResult GetProducts()

Example code

{
return Ok(new[] { "Laptop", "Mouse", "Keyboard" });
}

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.