Migration

Fetcher v1 is a ky wrapper, not a ky replacement. Migration should preserve ky defaults first, then add OpenAPI typing where it pays off.

From plain ky

const api = ky.create({ prefixUrl: '/api' });

becomes:

const api = createFetcher<paths>({ prefixUrl: '/api' });

Existing ky options, hooks, retry configuration, custom fetch, and extend composition can usually move over unchanged.

Prefer the grouped request shape.

api.get('/users/{id}', {
  params: {
    path: { id: '42' },
    query: { include: 'profile' },
  },
});

Some flat runtime compatibility remains for unknown or untyped calls, but official docs and type contracts use the grouped shape.

If an older helper returned parsed JSON directly, decide per boundary:

keep await api.get(...).json() when you want ky-style lazy parsing
use await api.safe.get(...) when you want parsed data and a non-throwing result

This preserves ky ergonomics while still offering a result-object style where it helps.