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.

Testcontainers on Artur Rios Lab

How I Develop APIs