api-testing

Test Next.js API endpoints by making HTTP requests to your local routes using curl or a similar tool. For example, curl -s "http://localhost:3000/api/inventory?limit=5" validates GET requests and returns the response payload, letting you verify status codes and JSON structure before deployment.

Debug authentication by first fetching a valid token, then including it in requests to protected endpoints. This workflow verifies token-based auth flows work correctly and helps identify 401/403 errors caused by missing, expired, or invalid credentials.

Validate response status codes across all request types: 200 for success, 400 for malformed requests, 401 for auth failures, 403 for forbidden access, 404 for missing routes, and 500 for server errors. Checking these codes ensures your API handles both happy paths and error cases correctly.

Yes. Test all HTTP methods—GET, POST, PUT, DELETE—by sending the appropriate requests with curl or similar tools, verifying response validation, status codes, and JSON payloads. Each method follows the same validation workflow to catch endpoint issues early.

After making a request, inspect the returned JSON payload against your expected schema. Check that all required fields are present, data types are correct, and nested objects align with your application's contract, catching structural mismatches before they reach production.

Isolate 400 errors by verifying request parameters, headers, and body format match your endpoint's expectations. For 500 errors, check server-side logic, database connections, and error logs. Use curl to reproduce errors in isolation and apply guided fixes based on the error response.