Controllers and Routing in ASP.NET Core Web API

Controllers and Routing in ASP.NET Core Web API

Controllers expose the HTTP surface of an API. Routing determines which action handles an incoming request.

Why This Matters

Routing is not just a URL concern. It shapes the public contract of the service, which means it affects discoverability, versioning, and maintainability.

Core Design Guidance

• keep route structures resource-oriented
• use HTTP verbs consistently
• return explicit status codes
• keep controllers thin and move business logic into services

Minimal Example

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    [HttpGet("{id:int}")]
    public IActionResult GetById(int id) => Ok(new { id });
}