When would you use minimal APIs instead of controllers in ASP.NET Core?

When would you use minimal APIs in ASP.NET Core?

Explains minimal APIs, endpoint groups, dependency injection, typed results, filters, and when they fit real services.

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TL;DR

Minimal APIs let me map endpoints directly with methods like MapGet, MapPost, or endpoint groups instead of writing controller classes. They still support dependency injection, binding, authorization, filters, and OpenAPI metadata. They work well for small services, focused internal APIs, health endpoints, and simple endpoint groups. They are not automatically better than controllers.

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Endpoint style judgment, maintainability, endpoint grouping, typed results, filters, and team conventions.

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Why this matters
Minimal APIs are common in modern ASP.NET Core, but a strong interview answer is not framework marketing. It explains where they are useful and when controllers still make sense.
Minimal APIs let me map endpoints directly with methods like MapGet, MapPost, or endpoint groups instead of writing controller classes. They still support dependency injection, binding, authorization, filters, and OpenAPI metadata. They work well for small services, focused internal APIs, health endpoints, and simple endpoint groups. They are not automatically better than controllers.
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Stronger answer
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I would use minimal APIs when the API surface is small or when endpoint definitions are clearer close to route configuration. For example, a small internal pricing service with ten endpoints can be clean with grouped minimal APIs and typed results. The trade-off is organization: if handlers grow large or everything lives in one file, minimal APIs become harder to maintain than controllers. I still keep application logic outside the handler.

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Putting every endpoint in Program.cs.
Skipping validation or consistent errors because the API is 'minimal'.
Mixing business logic directly into route lambdas.
Saying controllers are obsolete.
Saying minimal APIs are only for demos.

When would you use minimal APIs instead of controllers in ASP.NET Core?

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