How do I spin up a temporary mock API in 30 seconds?
Paste a JSON template with Faker-style tokens (e.g. `{{name.full}}`, `{{email}}`, `{{uuid}}`, `{{repeat(3,5)}}`), click "Create mock URL" and get a unique address at `/api/mock/{id}` that serves your data.
By default every call returns fresh random values (dynamic mode), or you can freeze the response (static mode). Configure the status code (200, 404, 500, …), the response delay (up to 5 seconds, to simulate slow APIs) and custom headers.
The mock lives for 7 days and then auto-deletes. Great for prototypes, frontend tests, demos without a backend, and mocking third-party APIs in E2E suites.
How to use it
- Paste a JSON template into the editor, or click "Insert sample" for a working starting point.
- Use tokens like `{{name.full}}`, `{{email}}`, `{{uuid}}`, `{{phone}}`, `{{number(1,100)}}`, `{{date.past}}`, `{{boolean}}`, `{{lorem(50)}}`, `{{address.city}}`, `{{url}}`, `{{color}}`, `{{ip}}`.
- Repeating arrays: `["{{repeat(3,5)}}", { ... }]` expands into an array of 3-5 rendered objects.
- Pick a status (200 / 201 / 204 / 400 / 404 / 500), a delay (0-5000 ms) and optionally custom headers.
- Toggle "Dynamic mode" - on = fresh random values every call, off = the same response every time.
- Click "Create mock URL". Copy the URL, the ready cURL line or a `fetch()` snippet and paste into your frontend / Postman / curl.
When this is useful
A mock API is the fastest way to build the frontend before the backend exists, or to simulate an edge case the real server can't easily reproduce:
- UI prototype with no backend. The designer demos at the meeting; the frontend dev already has realistic data wired up.
- E2E tests (Playwright, Cypress). A third-party service has a flaky API or a paid rate limit - mock the response and your test stays deterministic.
- Error simulation. How does your app behave on a 500, a 4-second timeout, or an empty 204? Change status / delay and find out.
- Customer demos. Show a dashboard with 50 orders - no real users, no DB seeding.
- Developer onboarding. New hires get a mock URL instead of a week of local environment setup.
- Postman / Insomnia / Bruno collections. Share a single URL with the team - they hit it and get data immediately.
- Education / workshops. Teaching `fetch()` / Axios / React Query - every example works, no need to run a server.
To validate the mock's response, see JSON formatter. To receive webhooks, webhook receiver.