How to Test API Endpoints Online for Free
Testing API endpoints is essential for developers building web services, but installing heavy tools like Postman isn't always practical. This guide shows you how to test any REST API endpoint directly in your browser using fixie.tools' free API tester - no installation, no signup, and your request data stays private.
Step 1: Choose Your HTTP Method and Enter the URL
Go to fixie.tools/api-tester and select the HTTP method you need (GET, POST, PUT, DELETE, PATCH, etc.). Enter the full API endpoint URL you want to test.
Step 2: Add Headers and Authentication
Click the Headers tab to add any custom HTTP headers your API requires. Common headers include Authorization for bearer tokens or API keys, Content-Type to specify JSON or XML payloads, and custom headers like X-API-Key.
Step 3: Set Request Body (For POST/PUT/PATCH)
If you're sending data to the API, click the Body tab and choose your format - JSON is most common. Enter your request payload in the text editor. The tool supports raw JSON, form data, and URL-encoded formats.
Step 4: Send Request and Inspect the Response
Click the Send Request button. The tool displays the complete HTTP response including status code (200, 404, 500, etc.), response headers, and response body. You can view the body as formatted JSON, raw text, or preview HTML responses. Response time is also shown.
Step 5: Debug Errors Using Status Codes and Headers
If your request fails, check the HTTP status code first. 401/403 usually means authentication issues. 404 means the endpoint doesn't exist. 500 errors indicate server problems. The response headers often contain debug information like rate limit status or error details.