Mock API Generator
Define mock API endpoints and export as Express, Flask, or JSON Server config.
Free & unlimited
GET/api/users200
Method
Path
Status
Description
Response body
All processing happens in your browser. No data is sent to any server.
About this tool
- 1
Define endpoints
Add API endpoints by specifying the HTTP method, path, and response status code.
- 2
Configure responses
Define response bodies with static JSON or use dynamic templates for realistic data.
- 3
Set headers and delays
Add custom response headers and optional latency to simulate real-world conditions.
- 4
Export the spec
Download the mock API definition as an OpenAPI spec or a Postman collection.
- Use dynamic templates like {{faker.name}} to generate realistic-looking response data.
- Add deliberate delays to test how your frontend handles slow API responses.
- Define error responses (400, 404, 500) alongside success responses for thorough testing.
- Group related endpoints under tags to keep your mock API organized.
- Visual endpoint builder with method, path, and response configuration
- Dynamic response templates with Faker.js-style placeholders
- Configurable response delays and error simulation
- Export as OpenAPI 3.0 spec or Postman collection
- Request/response logging for debugging integrations
- Build a mock backend so frontend development can proceed before the real API is ready
- Create realistic API stubs for automated integration tests
- Prototype an API design and share the spec with backend developers
- Simulate error scenarios like timeouts and 500 errors for resilience testing
Yes. You can require API keys or Bearer tokens and return 401 responses for unauthenticated requests.
Set a delay in milliseconds for any endpoint. This is useful for testing loading states and timeout handling.
Yes. Export your mock API as a Postman collection JSON file that can be imported directly into Postman.