π Target URL
π Requests go directly from your browser. This tool does NOT log any data.
Free online CORS test tool, pure client-side. Check if a URL supports cross-origin requests. Displays CORS response headers and preflight results to help debug cross-origin issues.
π 100% Client-SideFollow these simple steps. All processing happens locally in your browser.
CORS (Cross-Origin Resource Sharing) is a browser security mechanism that controls how web pages request resources from different origins. If the server doesn't set proper CORS headers, the browser blocks the request.
CORS test focuses on checking cross-origin headers (Access-Control-Allow-Origin etc.), while API test focuses on actual response data. This tool provides both: GET test and OPTIONS preflight.
A preflight is an OPTIONS request the browser sends before certain cross-origin requests to check if the server permits them. This tool lets you manually send preflight requests.
A CORS proxy is a middleman server that adds CORS headers when fetching APIs. Popular options: corsproxy.io, cors-anywhere. Note: your data passes through the proxy server.
CORS support depends on the API server. Public APIs usually support CORS. Private/legacy systems may not. Server-side middleware (like the `cors` npm package) can enable it.
This tool runs 100% in your browser using modern web technologies. No data is ever sent to any server.