CORS (Cross-Origin Resource Sharing) headers are HTTP headers that control how web browsers handle requests between different origins. When your frontend application makes a request to an API on a different domain, these headers determine whether the browser allows the response to be read.
This resource provides comprehensive documentation for all CORS-related headers, including syntax, practical examples, common errors, and solutions. Whether you're troubleshooting a CORS error or implementing secure cross-origin access, you'll find the information you need here.
All CORS Headers
Access-Control-Allow-Origin
Define which origins are allowed to access cross-origin resources.
Access-Control-Allow-Credentials
Determine if credentials (cookies, authentication headers) can be included.
Access-Control-Allow-Headers
Specify which headers clients can use in cross-origin requests.
Access-Control-Allow-Methods
Specify which HTTP methods are allowed in cross-origin requests.
Access-Control-Expose-Headers
Enable client-side JavaScript to read non-standard response headers.
Access-Control-Max-Age
Reduce latency by caching preflight results for faster requests.
Access-Control-Request-Headers
Lists the headers the client intends to send with the actual request.
Access-Control-Request-Method
Specifies the HTTP method the client plans to use in the actual request.
Origin
Indicates where the request originated from (scheme, hostname, port).
When Do You Need This Resource
For Web Developers
Use this resource when your frontend application needs to interact with APIs on different origins. You'll find detailed explanations of CORS errors, step-by-step solutions, and code examples to help you troubleshoot and fix cross-origin issues quickly.
For API Makers
Learn how to configure CORS headers correctly to enable secure client-side access to your API. Understand which headers to use for different scenarios, from public APIs to authenticated endpoints, and how to implement proper security controls.
Explore More Tools
CORS Tester
Paste any API endpoint and instantly see if it supports CORS and which headers it returns. Perfect for debugging and verifying your CORS configuration.
CORS Proxy Playground
Bypass CORS errors in development by routing your requests through our CORS proxy. Test and experiment with cross-origin requests in a safe environment.