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API Mock Response Generator

LOCAL · Browser-Only

Generate mock API responses for testing

Response Template

Content Type

HTTP Method

Status Code

Items Count

Response Delay (ms)

Seed (optional)

Response Body

Select a template and click Generate to create a mock response

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What is API Mock Response Generator?

Free online API mock response generator to generate realistic mock API responses for development and testing.

Create fake JSON for a REST API, build a mock user list or product catalog, and generate sample error responses like 401 and 404. Choose from common response patterns (user list, product catalog, authentication, pagination, error responses) or build custom JSON structures. Configure status codes, headers, and response bodies. Copy the complete response object for use in tests, mock servers, and frontend development. No signup required.

How to Use API Mock Response Generator

1Select a response template (user list, auth, error, etc.)
2Customize the response body, status code, and headers
3Set the number of items and data patterns
4Copy the complete mock response for your tests

Frequently Asked Questions

What response templates are available?

User list, single user, product catalog, authentication (login/register), paginated list, error responses (400, 401, 403, 404, 500), and empty/null responses. Each template is realistic and follows REST conventions.

Can I customize the response?

Yes. Start from a template and modify the JSON structure, change status codes, add custom headers, and adjust the number of items. You can also write responses from scratch.

How do I use this with my frontend?

Copy the mock response and use it with libraries like MSW (Mock Service Worker), json-server, or simply hardcode it in your tests. The response format matches what real APIs return.

How do I generate fake JSON for a REST API?

Pick a template such as user list or product catalog, set how many items you want, then copy the JSON. The output follows REST conventions so it drops straight into a mock server or test fixture.

Can I create mock error responses?

Yes. Choose an error template like 400, 401, 403, 404, or 500 to get a realistic error body and status code. This is useful for testing how your frontend handles failed requests.

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Keep reading: Git Cheat Sheet and http status codes reference. Doing this in code instead? See the utility endpoints.

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