Typed Routes

Typed routes is an Expo Router feature that turns the files in your app/ directory into TypeScript types. Every href you pass to <Link>, router.push() or router.replace() is checked against the routes that actually exist, including the names of dynamic segments.

<Link href="/settings">Settings</Link>
<Link href={{ pathname: '/post/[id]', params: { id: '42' } }}>Post</Link>

router.push('/setings'); // type error: route does not exist

It matters because navigation strings are the one part of a React Native app the compiler usually cannot see. Renaming profile.tsx to account.tsx used to leave broken links that only showed up when someone tapped them, or when a push notification deep link silently landed on a not-found screen. With typed routes the rename produces a list of type errors.

How it works in practice:

• It is switched on in app config (historically under experiments.typedRoutes; check the Expo Router docs for your SDK).
• The Expo CLI writes the generated declarations into the .expo folder and references them from an expo-env.d.ts file in the project root.
• The types are regenerated while the dev server runs, so adding a file updates autocomplete straight away.

The gotcha is that the types are generated, not written. On a fresh clone or in CI, a type-check can fail with errors about every href until the Expo CLI has produced the declarations, and committing a stale copy causes the opposite problem. Run the generation step before tsc in CI rather than checking the files in.

Typed routes check the shape of URLs your code builds. They cannot validate URLs that arrive from outside at runtime, such as links from emails, so the not-found route still matters. See typed routes.