How we build our products.
Engineering write-ups from the apps we ship and run, with a soft spot for the old devices most apps leave behind.
13 months, $1.5 billion, and one uncomfortable question: the Emergent.sh story
Emergent closed a $130M Series C at 5x its valuation from four months earlier. None of its 200,000 customers know how to code. And it runs on models built by the lab that should be its most dangerous competitor.
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ProFocus Jul 4, 2026 · 4 min read Running on a 2013 phone: the low-end tech stack behind ProFocus
ProFocus turns a spare phone into a desk clock, focus timer, and WiFi photo frame. Supporting that means running on Android 4.3 and iOS 12, with no Firebase and no Play Services. Here is how.
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Hack Não English Jul 4, 2026 · 4 min read Learning English offline: the methods and on-device AI behind Hack Não English
Hack Não English teaches 1500 words across iOS, Android, web, and macOS, with an AI pronunciation and grammar coach that runs entirely on the phone. Here are the learning methods and the cross-platform, on-device stack that powers them.
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GoBrain Jul 4, 2026 · 3 min read One H5 codebase, native on iOS 12: the GoBrain tech stack
How we ship a PixiJS puzzle game to iOS, Android, and the web from a single TypeScript codebase, with over-the-air updates that still reach iOS 12 devices.
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