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Last updated · CalcoWorks
Overview
About Mock API Generator
Frontend work often stalls waiting on a backend that is not ready yet. A mock REST endpoint returns fixed JSON with the status code, headers, and latency you choose so UI teams can keep shipping screens, loading states, and error paths without blocking on services.
CalcoWorks Mock API Generator turns a JSON paste into a temporary public URL under /api/mock/{token}. Configure method, status, delay, custom headers, and expiry, then hit the endpoint from any fetch client, Postman, or your app. No account is required for creating short-lived mocks.
Use the on-page playground to copy the URL, open it, and send test requests. Request counts and a recent activity log help you confirm traffic while you iterate on the stored response body. Ready-made snippets for Fetch, Axios, cURL, Python, Node, PHP, Java, and C# speed up client wiring.
Keep mocks temporary and free of secrets. Prefer redacted fixtures. When the real API lands, switch base URLs and delete or let the mock expire.
Benefits
- Generate a live REST URL in seconds
- Control status codes for success and error UI
- Simulate latency with response delay
- Add custom response headers
- Edit JSON without regenerating the token
- Track request count and recent hits
- CORS-friendly for local frontend apps
- No signup for everyday frontend testing
- Delete when you are done
- Pairs with JSON Formatter and Validator
Use cases
- Prototype screens before the backend ships
- Demonstrate API contracts in demos
- Test loading spinners with deliberate delay
- Trigger 401/403/404 UI states
- Share a temporary fixture URL with a teammate
- Validate client retry behaviour
- Workshop teaching REST response shapes
- Smoke-test webhooks consumers with static JSON
- QA scripts that need a stable endpoint
- Mobile app mocking on the same Wi-Fi network
Examples
Example 1
Happy path user
GET 200 with a sample user object for profile pages.
Preview: open Mock API Generator and recreate this scenario with your numbers.Example 2
Unauthorized gate
GET 401 JSON error to verify redirect-to-login UI.
Preview: open Mock API Generator and recreate this scenario with your numbers.Example 3
Slow network
200 with 2000 ms delay to exercise skeletons.
Preview: open Mock API Generator and recreate this scenario with your numbers.Example 4
Create resource
POST 201 with an id field returned after create forms.
Preview: open Mock API Generator and recreate this scenario with your numbers.
How to use Mock API Generator
- 1
Open Mock API Generator
Go to Developer Tools → Mock API Generator.
- 2
Paste JSON
Enter the response body you want the endpoint to return.
- 3
Validate or format
Use Format/Validate so the payload is syntactically correct.
- 4
Choose options
Pick method, status code, delay, headers, and expiry.
- 5
Generate
Create the endpoint and copy the unique URL.
- 6
Test
Send a request from the playground or your app.
- 7
Edit or delete
Update the body/status later, or delete when finished.
Frequently asked questions
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