When Minimal APIs came out in .NET 6, they quickly became popular for building fast and lightweight web services. However, earlier versions didn’t have a good way to handle common tasks like validation, logging, or authorization without repeating the same code.
That’s where Endpoint Filters come in — first introduced in .NET 7, improved in .NET 8, and now even better in .NET 9 with easier usage, grouping options, and more control over the request pipeline.
In this post, we’ll look at Filters in Minimal APIs with .NET 9 — how they work and how you can use them effectively with modern best practices.