API Response Mocker

Create mock API responses with custom status codes, headers, and JSON payloads.

HTTP Status Code: Common: 200 (OK), 201 (Created), 400 (Bad Request), 401 (Unauthorized), 404 (Not Found), 500 (Server Error)

Response Body (JSON):

Custom Headers (one per line):

Generate Mock Response Reset

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How to Use the API Response Mocker

This tool helps you design and visualize API responses before implementing your backend, making frontend development faster and more independent.

Step-by-Step Instructions:

1. Choose a status code: Select an appropriate HTTP status code (200 for success, 404 for not found, etc.)
2. Write your JSON response: Enter the JSON structure you want your API to return
3. Add custom headers: (Optional) Add headers like Content-Type, Cache-Control, etc.
4. Generate: Click "Generate Mock Response" to see the formatted result
5. Copy & use: Copy the response to use in your frontend code or documentation

Example Use Cases:

• Frontend Development: Build UI components before the backend API is ready
• Error Handling: Test how your app handles different error responses (400, 401, 500)
• Documentation: Create example responses for API documentation
• Contract Testing: Define API contracts between frontend and backend teams
• Demo & Prototyping: Create realistic mock data for demos and prototypes

Example Mock Responses:

Success Response (200):

{
  "status": "success",
  "data": {
    "id": 123,
    "username": "johndoe",
    "email": "john@example.com",
    "created_at": "2024-01-15T10:30:00Z"
  }
}

Error Response (404):

{
  "status": "error",
  "error": {
    "code": "NOT_FOUND",
    "message": "User not found",
    "details": "No user exists with ID 999"
  }
}

Validation Error (400):

{
  "status": "error",
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid request data",
    "fields": {
      "email": "Invalid email format",
      "password": "Password must be at least 8 characters"
    }
  }
}

Common HTTP Status Codes:

• 200 OK: Request succeeded
• 201 Created: Resource created successfully
• 204 No Content: Success with no response body
• 400 Bad Request: Invalid request data
• 401 Unauthorized: Authentication required
• 403 Forbidden: Access denied
• 404 Not Found: Resource doesn't exist
• 500 Internal Server Error: Server error

Related Tools:

• HTTP Status Codes Reference - Complete status code guide
• JSON Beautifier - Format and validate JSON
• JSON Schema Generator - Generate schemas from JSON
• OpenAPI Validator - Validate API specifications
• JSON Faker - Generate fake JSON data