TypeScript at Craftzing, Belgium. Expo apps and the APIs behind them.

Mostly I care that the types are honest at the boundary. On the API side that means generating them from a TypeSpec contract instead of maintaining them by hand. On the Expo side it means checking the TypeScript surface against what the Swift and Kotlin actually do — when they disagree, the types are the bug.

Working with TypeScript · Expo · React-Native · TypeSpec / OpenAPI · Zod · Effect · ts-pattern · NestJS

Recent upstream work

• expo/expo — anchor support for Apple Maps annotations, and two fixes to iOS camera barcode scanning where the ZXing fallback path disagreed with AVFoundation on type strings
• microsoft/typespec — a dropped discriminator.mapping entry when the first union variant caused a circular emit
• react-native-passkey — Android Credentials 1.6.0 / Android 15 support, and realigning the TypeScript types with what the native implementations actually do
• facebook/react-native — custom fonts rendering the heaviest face on iOS Fabric when combined with an explicit fontWeight

How I like to build

• Contract-first. The API is authored in TypeSpec, compiled to OpenAPI, and the types, Zod schemas, controller interfaces and SDK are generated from it — implementation and docs can't drift apart.
• Typed domains. DDD and hexagonal ports & adapters, making illegal states unrepresentable rather than validating after the fact.
• Architecture you can read. C4 levels as Mermaid in the repo, updated in the same PR as the code.
• Declarative machines. Fedora + mise + chezmoi: a laptop is one command from ready.