Justin Horn

Four years of building integration architectures, modernizing legacy apps, and shipping developer tooling.

I've worked across the full spectrum — from a Flutter mobile app and Firebase backend at a startup, to leading refactors and introducing code conventions at a product company, to designing and maintaining integration systems, Electron apps, and CI/CD pipelines at Markup AI.

"The best work happens when you respect what came before and still have the courage to change it."

I've spent years moving between greenfield prototypes and deeply rooted legacy systems. That taught me something: the urge to rewrite everything from scratch is almost always wrong. Real skill is understanding a codebase on its own terms, then improving it piece by piece — not burning it down.

I believe in ownership. Not the performative kind, but the quiet kind — seeing a gap, filling it, and not waiting for someone to assign it to you. Some of the work I'm proudest of started as problems nobody asked me to solve: a missing CI pipeline, a convention the team needed, a refactor that made the next six months easier for everyone.

Frontend, integrations, tooling, infrastructure — I'd rather understand the full picture than master one corner of it. Tests, conventions, and clear architecture aren't bureaucracy — they're how you build things that last beyond the sprint they shipped in.