I built a tool that generates TypeScript fixtures from interfaces and Zod schemas

A developer built FixtureKit, a free browser-based tool that generates TypeScript mock data fixtures from interfaces, types, or Zod schemas. The tool uses semantic field inference to produce realistic values and deterministic output based on field name hashes, supporting up to five fixtures at once without any backend or eval operations.

Every TypeScript project reaches the same point: you've defined your types, now you need mock data for tests, Storybook stories, or local dev. You end up hand-writing the same boilerplate mockUser , mockProduct , mockOrder objects over and over. I built FixtureKit to fix that — a free developer tool, not a product pitch. Paste a TypeScript interface , type , or a Zod z.object ... schema → get a copy-ready export const mock… TypeScript fixture. Try it: https://fixture-kit.vercel.app https://fixture-kit.vercel.app Input: interface Product { id: string; name: string; price: number; inStock: boolean; tags: string ; } Output: js export const mockProduct: Product = { id: "f47ac10b-58cc-4372-a567-0e02b2c3d479", name: "Wireless Keyboard", price: 49.99, inStock: true, tags: "electronics", "accessories" , }; What makes it useful Semantic field inference — it doesn't just fill every string with "value". Field names like email, name, url, price, createdAt map to realistic value pools. Type compatibility is enforced: you won't get an email string on a number field. Deterministic output — uses a hash of the field name + fixture index. No Math.random . Same schema always gives the same output. Safe to commit. No eval, no backend — Zod schemas parsed with a custom recursive-descent parser. TypeScript schemas use the TypeScript compiler API. Everything runs in the browser. Generate up to 5 fixtures at once — useful for seeding UI components or table/list test cases. Supported input TypeScript: interface, type, arrays, nested objects, optional fields, unions, literal types Zod: z.object, z.string, z.number, z.boolean, z.array, z.enum, z.union, z.literal, .optional , .nullable , nested z.object Advanced features generics, utility types, .refine, .transform are out of scope and return a clear error. Tech React 18 · TypeScript 5 · Vite · TypeScript compiler API in-browser Source https://github.com/Wasef-Hussain/FixtureKit https://github.com/Wasef-Hussain/FixtureKit Feedback welcome — especially on schema shapes I haven't handled well.