Free Online API Tester
Send HTTP requests from your browser. Test CORS-enabled APIs instantly — no signup required.
Request Blocked by CORS Policy
The server does not include Access-Control-Allow-Origin headers. Browsers block these responses for security.
What is API Testing?
API testing involves sending HTTP requests to an API endpoint and verifying the response. It ensures that APIs return correct data, handle errors properly, and meet performance requirements. API testing is essential in modern software development where microservices and third-party integrations are common.
HTTP Methods Explained
GET retrieves data from a server. POST creates new resources. PUT replaces existing resources entirely. PATCH partially updates resources. DELETE removes resources. HEAD is like GET but returns only headers. OPTIONS returns supported methods (used in CORS preflight).
Understanding CORS
CORS (Cross-Origin Resource Sharing) is a browser security mechanism that restricts web pages from making requests to different domains. When you test an API from a browser, the server must include Access-Control-Allow-Origin headers to permit the request. Most APIs don't include these headers for browser requests, which is why desktop tools like RestForge work without CORS restrictions.
Browser vs Desktop API Testing
Browser-based API testers are convenient for quick tests on CORS-enabled APIs. However, for professional API testing that requires custom headers, authentication, request scripting, environment variables, and testing against any server, a native application like RestForge provides the full experience without browser limitations.
Need Full API Testing Power?
Download RestForge for unlimited API testing without CORS restrictions, plus scripting, environments, cloud sync, and more.