About

The name

The double-slit experiment was the first physics experiment my father showed me as a kid. Two slits, one particle, and a result that changes because you looked. It stuck with me as a symbol of how observation shapes reality, and years later it named my company, Double Slit Apps. This site is that idea, one abstraction up. Everything here is reality as observed by me.

That's also my honest description of building with AI. The craft is increasingly observation: you watch agents work, you notice what matters, and what you notice shapes what gets built.

The record

I'm Filipe Alvarenga. I've spent more than a decade building native iOS apps used by millions: Swift, UIKit, SwiftUI, and yes, Objective-C. I've worked at several startups along the way; led some, founded some. I know the full life of a shipped app, from architecture to App Store review to the subscription stack.

In March 2024 I committed publicly to building with AI and started documenting it. Since then I've shipped TMCBAE and Postr almost entirely by prompting, built a working backend in under eight hours with close to zero prior backend experience, and written it all up, failures included.

Now

I'm building pinned.social: local recommendations from your friends instead of the algorithm. And I'm writing here about what building with AI is actually like, from inside the work.