About

I'm Diego Castillo, a software engineer and builder. I focus on craftsmanship and simple, thoughtful products.

I work at Buffer, a fully remote team building social media tools for creators and small businesses. Most of my time goes to the parts developers and agents build on top of. I write mostly in TypeScript, Elixir, and Ruby.

On the side I build my own things, like ToneBuilder and Momentum. A few more are on the products page. I also play jazz as @diegocasmo.

This blog is where I think out loud about software, building with AI, and the occasional CS rabbit hole.

My work history is on my resume and LinkedIn. You can also find me on GitHub and X.