Minimal APIs vs. Controllers in ASP.NET Core

• JD

  John Doe

  Posted: 2023-10-27 10:30 AM

  Hi everyone,

  I'm working on a new ASP.NET Core project and I'm trying to decide whether to go with Minimal APIs or traditional Controllers for my endpoints. I understand the basic differences, but I'd love to hear from those who have experience with both. What are the real-world pros and cons of each approach?

  Specifically, I'm interested in:

  • Scalability: Which approach is generally more scalable for larger applications?
  • Maintainability: How does the code organization and ease of maintenance differ?
  • Performance: Are there any significant performance differences?
  • Testability: Which approach makes unit testing easier?
  • Use cases: When would you strongly recommend one over the other?

  Any insights or examples would be greatly appreciated!

  Thanks!

• AS

  Alice Smith

  Posted: 2023-10-27 11:15 AM

  Great question, John!

  I've used both extensively. For smaller projects or microservices, Minimal APIs can be incredibly concise and efficient. The boilerplate is significantly reduced. For example:

  // Minimal API Example
  var builder = WebApplication.CreateBuilder(args);
  var app = builder.Build();
  
  app.MapGet("/", () => "Hello World!");
  
  app.Run();

  Controllers, on the other hand, shine in larger, more complex applications where you need more structure. They offer better separation of concerns, easier management of routes, and more straightforward integration with features like dependency injection and filters for a whole controller class.

  Scalability: For very large applications, controllers often provide a more manageable structure. Minimal APIs can become harder to navigate if you have hundreds of endpoints defined in a single file. However, you can split Minimal APIs into multiple files or use the `MapGroup` feature for better organization.

  Maintainability: Controllers generally win here for complexity. The class-based structure is very clear. Minimal APIs can get messy if not managed carefully. Splitting them into logical groups and services is crucial.

  Performance: The performance difference is usually negligible in most real-world scenarios. Minimal APIs might have a slight edge due to less overhead, but it's rarely a deciding factor.

  Testability: Both are testable. Controllers can be tested by mocking dependencies injected into the controller. Minimal APIs can be tested by setting up a minimal `WebApplication` host and sending requests to specific endpoints.

  Recommendation:

  • Minimal APIs: Ideal for simple CRUD operations, microservices, or when you want to keep the API surface small and reduce boilerplate.
  • Controllers: Better for larger, enterprise-level applications with complex business logic, extensive use of filters, or when you prefer a more structured, class-based approach.

  Hope this helps!

• MJ

  Mark Johnson

  Posted: 2023-10-27 11:45 AM

  Building on Alice's excellent points, I've found that a hybrid approach can also be very effective. You might use Minimal APIs for very simple, common endpoints (like health checks or basic data retrieval) and then switch to controllers for more complex operations or areas that require extensive cross-cutting concerns handled by filters.

  One thing to consider with Minimal APIs is how you handle dependency injection. While it's perfectly supported, the syntax can sometimes feel a bit more inline compared to the constructor injection you're used to with controllers.

  // DI in Minimal API
  app.MapGet("/items/{id}", async (int id, IMyService service) => await service.GetItemAsync(id));

  This is very clean for simple cases but can become less readable if you have many injected services.

  For testing Minimal APIs, I've had good success with the built-in testing utilities in ASP.NET Core, which allow you to create an in-memory web host.

  // Test Example
  [Fact]
  public async Task Get_EndpointReturnsSuccess()
  {
      var app = CreateMinimalApiApp(); // Helper to build the app
      var client = new TestClient(app);
  
      var response = await client.GetAsync("/items/1");
      response.EnsureSuccessStatusCode();
      // Assert response content
  }

• JD

  John Doe

  Posted: 2023-10-27 12:05 PM

  Thanks, Alice and Mark! Your insights are very helpful. The hybrid approach sounds like a good compromise for many scenarios. I'll definitely keep the organization and testability aspects in mind as I make my decision. The code examples really clarify the differences.