Built-in API Tester

Mock API Builder includes a powerful built-in API testing tool, similar to Postman, that lets you test your endpoints without leaving the application.

Key Features

✓ Test all HTTP methods (GET, POST, PUT, PATCH, DELETE)
✓ View formatted JSON responses
✓ Inspect response headers and status codes
✓ Measure response times
✓ Save and reuse requests
✓ Test with custom headers and query parameters

Testing Different HTTP Methods

GET

Testing GET Requests

Retrieve data from your endpoints

Get All Users:

GET https://www.mockapibuilder.io/api/users

Get Single User:

GET https://www.mockapibuilder.io/api/users/1

With Query Parameters:

GET https://www.mockapibuilder.io/api/users?page=1&limit=10

Expected Response:

200 OK

POST

Testing POST Requests

Create new resources

Endpoint:

POST https://www.mockapibuilder.io/api/users

Headers:

Content-Type: application/json

Body:

{
  "name": "John Doe",
  "email": "john@example.com"
}

Expected Response:

201 Created

PUT

Testing PUT Requests

Update entire resources

Endpoint:

PUT https://www.mockapibuilder.io/api/users/1

Body:

{
  "name": "John Smith",
  "email": "john.smith@example.com"
}

Expected Response:

200 OK

DELETE

Testing DELETE Requests

Remove resources

Endpoint:

DELETE https://www.mockapibuilder.io/api/users/1

Expected Response:

204 No Content

Using External Tools

You can also test your APIs using popular external tools:

cURL (Command Line)

GET Request:

curl https://www.mockapibuilder.io/api/users

POST Request:

curl -X POST https://www.mockapibuilder.io/api/users \ -H "Content-Type: application/json" \ -d '{"name":"John Doe"}'

Postman

Open Postman
Create a new request
Enter your endpoint URL
Select HTTP method
Add headers Authorization (Bearer API token)
Click Send

Frontend JavaScript (fetch)

// GET request
const BASE_URL = process.env.NEXT_PUBLIC_BASE_URL || 'http://localhost:3000';
const response = await fetch(`${BASE_URL}/api/users`);
const users = await response.json();

// POST request
const response = await fetch(`${BASE_URL}/api/users`, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    name: 'John Doe',
    email: 'john@example.com'
  })
});

Understanding Response Codes

2xx

Success Responses

• 200 OK - Request successful

• 201 Created - Resource created successfully

• 204 No Content - Success, no response body

4xx

Client Error Responses

• 400 Bad Request - Invalid request data

• 401 Unauthorized - Authentication required

• 404 Not Found - Resource doesn't exist

• 429 Too Many Requests - Rate limit exceeded

5xx

Server Error Responses

• 500 Internal Server Error - Server error

• 503 Service Unavailable - Server overloaded

Common Issues & Solutions

CORS Errors

Problem: "Access to fetch blocked by CORS policy"

Access-Control-Allow-Origin error

Solution: Mock API Builder automatically handles CORS. If testing from a different domain:

• Ensure your dev server is running on localhost
• Check if you're using the correct port (3000)
• CORS headers are automatically set for all origins

404 Not Found

Problem: Endpoint returns 404 error

Checklist:

✓ Verify the endpoint path matches exactly
✓ Check if the project slug is correct
✓ Ensure the endpoint was saved in project settings
✓ Confirm the HTTP method is enabled for this endpoint

Invalid JSON Response

Problem: Response is not valid JSON

Solution:

• Check your schema definition for syntax errors
• Ensure all mock data follows the schema
• Look for missing commas or brackets
• Use the JSON validator in the schema editor

Slow Response Times

Problem: API responses are taking too long

Solutions:

• Reduce the number of mock records (try 100 instead of 10,000)
• Simplify nested objects in your schema
• Use pagination for large datasets
• Check database connection in logs

Debugging with Request Logs

Every API request is automatically logged for debugging:

Request Log Details

Each log entry shows:

• Timestamp (when the request was made)
• HTTP method and endpoint path
• Status code (200, 404, 500, etc.)
• Response time (in milliseconds)
• Request headers and body
• Query parameters
• Client IP address

Access Logs:

Go to your project → Logs tab to view all requests

Testing Best Practices

✓ Test All HTTP Methods

Don't just test GET requests. Verify POST, PUT, PATCH, and DELETE work correctly.

✓ Test Edge Cases

• Invalid IDs (non-existent resources)
• Empty request bodies
• Very large payloads
• Special characters in data

✓ Monitor Response Times

API responses should be under 200ms for good UX. Use logs to track performance.

✓ Test from Your Frontend

After testing with tools, integrate with your actual frontend app to ensure everything works end-to-end.

Built-in API Tester

Mock API Builder includes a powerful built-in API testing tool, similar to Postman, that lets you test your endpoints without leaving the application.

Key Features

✓ Test all HTTP methods (GET, POST, PUT, PATCH, DELETE)
✓ View formatted JSON responses
✓ Inspect response headers and status codes
✓ Measure response times
✓ Save and reuse requests
✓ Test with custom headers and query parameters

Testing Different HTTP Methods

GET

Testing GET Requests

Retrieve data from your endpoints

Get All Users:

GET https://www.mockapibuilder.io/api/users

Get Single User:

GET https://www.mockapibuilder.io/api/users/1

With Query Parameters:

GET https://www.mockapibuilder.io/api/users?page=1&limit=10

Expected Response:

200 OK

POST

Testing POST Requests

Create new resources

Endpoint:

POST https://www.mockapibuilder.io/api/users

Headers:

Content-Type: application/json

Body:

{
  "name": "John Doe",
  "email": "john@example.com"
}

Expected Response:

201 Created

PUT

Testing PUT Requests

Update entire resources

Endpoint:

PUT https://www.mockapibuilder.io/api/users/1

Body:

{
  "name": "John Smith",
  "email": "john.smith@example.com"
}

Expected Response:

200 OK

DELETE

Testing DELETE Requests

Remove resources

Endpoint:

DELETE https://www.mockapibuilder.io/api/users/1

Expected Response:

204 No Content

Using External Tools

You can also test your APIs using popular external tools:

cURL (Command Line)

GET Request:

curl https://www.mockapibuilder.io/api/users

POST Request:

curl -X POST https://www.mockapibuilder.io/api/users \ -H "Content-Type: application/json" \ -d '{"name":"John Doe"}'

Postman

Open Postman
Create a new request
Enter your endpoint URL
Select HTTP method
Add headers Authorization (Bearer API token)
Click Send

Frontend JavaScript (fetch)

// GET request
const BASE_URL = process.env.NEXT_PUBLIC_BASE_URL || 'http://localhost:3000';
const response = await fetch(`${BASE_URL}/api/users`);
const users = await response.json();

// POST request
const response = await fetch(`${BASE_URL}/api/users`, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    name: 'John Doe',
    email: 'john@example.com'
  })
});

Understanding Response Codes

2xx

Success Responses

• 200 OK - Request successful

• 201 Created - Resource created successfully

• 204 No Content - Success, no response body

4xx

Client Error Responses

• 400 Bad Request - Invalid request data

• 401 Unauthorized - Authentication required

• 404 Not Found - Resource doesn't exist

• 429 Too Many Requests - Rate limit exceeded

5xx

Server Error Responses

• 500 Internal Server Error - Server error

• 503 Service Unavailable - Server overloaded

Common Issues & Solutions

CORS Errors

Problem: "Access to fetch blocked by CORS policy"

Access-Control-Allow-Origin error

Solution: Mock API Builder automatically handles CORS. If testing from a different domain:

• Ensure your dev server is running on localhost
• Check if you're using the correct port (3000)
• CORS headers are automatically set for all origins

404 Not Found

Problem: Endpoint returns 404 error

Checklist:

✓ Verify the endpoint path matches exactly
✓ Check if the project slug is correct
✓ Ensure the endpoint was saved in project settings
✓ Confirm the HTTP method is enabled for this endpoint

Invalid JSON Response

Problem: Response is not valid JSON

Solution:

• Check your schema definition for syntax errors
• Ensure all mock data follows the schema
• Look for missing commas or brackets
• Use the JSON validator in the schema editor

Slow Response Times

Problem: API responses are taking too long

Solutions:

• Reduce the number of mock records (try 100 instead of 10,000)
• Simplify nested objects in your schema
• Use pagination for large datasets
• Check database connection in logs

Debugging with Request Logs

Every API request is automatically logged for debugging:

Request Log Details

Each log entry shows:

• Timestamp (when the request was made)
• HTTP method and endpoint path
• Status code (200, 404, 500, etc.)
• Response time (in milliseconds)
• Request headers and body
• Query parameters
• Client IP address

Access Logs:

Go to your project → Logs tab to view all requests

Testing Best Practices

✓ Test All HTTP Methods

Don't just test GET requests. Verify POST, PUT, PATCH, and DELETE work correctly.

✓ Test Edge Cases

• Invalid IDs (non-existent resources)
• Empty request bodies
• Very large payloads
• Special characters in data

✓ Monitor Response Times

API responses should be under 200ms for good UX. Use logs to track performance.

✓ Test from Your Frontend

After testing with tools, integrate with your actual frontend app to ensure everything works end-to-end.

API Testing & Debugging

Built-in API Tester

Key Features

Testing Different HTTP Methods

Using External Tools

Understanding Response Codes

Common Issues & Solutions

Debugging with Request Logs

Testing Best Practices

API Testing & Debugging

Built-in API Tester

Key Features

Testing Different HTTP Methods

Using External Tools

Understanding Response Codes

Common Issues & Solutions

Debugging with Request Logs

Testing Best Practices