How I Develop APIs

Wed, 21 Oct 2026 19:30:00 +0000

Every backend I build is an ASP.NET Core API, and they all look alike on purpose. When the structure is the same everywhere, I never have to remember where a thing lives, a new feature is a list of files to add rather than a design decision, and a test that fails points at one small piece of code.

This page describes that shape, using Heimdall as the example throughout. Heimdall is my identity management API: people, applications, logins, two-factor authentication and permissions, for several client systems at once, each in its own scope. It is the largest API I have, so every pattern here has been tested against a real use case rather than a toy one. All code on this page is taken from it, trimmed only where noted.

The .NET Libraries I Reach For

Wed, 21 Oct 2026 13:20:00 +0000

Every new .NET project starts with the same handful of decisions. How will I test it? Where does fake data come from? How do I validate input, survive a flaky dependency, export a spreadsheet, run something every night? The base class library answers some of these. For the rest, I have settled on a short list of NuGet packages that I add almost without thinking.

This page is that list, with the reasoning written down. For each library I explain what it is for, why I use it, show a small example and say when I would pick something else. A recommendation is only as good as what it leaves out, so I also flag what I would want to know before adding a dependency: licence, maintenance, breaking changes, and in two cases events that every user of the library should know about.

XUnit on Artur Rios Lab

How I Develop APIs

The .NET Libraries I Reach For