CORS Header Generator
Web & SEOGenerate the correct Access-Control-Allow-Origin, Methods, Headers, and other CORS response headers for your API or web server configuration.
Quick Presets
Allowed Origin
Use * for public APIs or a specific origin for credentialed requests.
Permissions
Allowed Methods
Allowed Request Headers
Exposed Response Headers (optional)
Preflight Max-Age
24hoff1h12h24h
Security Assessment
Wildcard origin allows any website to access this API.
Configuration looks valid for CORS.
Access-Control-Allow-Origin
*
Access-Control-Allow-Methods
GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Headers
Content-Type, Authorization
Access-Control-Max-Age
86400
Access-Control-Allow-Origin: * Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS Access-Control-Allow-Headers: Content-Type, Authorization Access-Control-Max-Age: 86400
About CORS Header Generator
The CORS Header Generator helps you build the exact set of Access-Control-* HTTP response headers needed to implement a correct Cross-Origin Resource Sharing policy for your API or web server. Configure the allowed origins (wildcard or specific domains), permitted HTTP methods, exposed and allowed request headers, credentials mode, and preflight cache duration. The tool outputs ready-to-use header values you can paste into your Nginx, Apache, Express, or any other server configuration.
Features
- ✓Access-Control-Allow-Origin with wildcard or specific origin support
- ✓Access-Control-Allow-Methods selector for GET, POST, PUT, DELETE, PATCH, OPTIONS
- ✓Access-Control-Allow-Headers and Access-Control-Expose-Headers configuration
- ✓Access-Control-Allow-Credentials toggle for cookie and auth header sharing
- ✓Access-Control-Max-Age input for pre-flight response caching
- ✓Output formatted for Nginx, Apache .htaccess, and generic header key-value pairs
- ✓Inline explanation of each header and its security implications
Common Use Cases
- Configuring CORS headers for a REST API consumed by a JavaScript frontend
- Fixing 'No Access-Control-Allow-Origin header' browser errors during development
- Setting up CORS on an S3 bucket or CDN for font or asset serving
- Allowing specific partner domains to call your API while blocking others
- Configuring credentials-enabled CORS for cookie-based authentication
- Generating Nginx add_header directives ready to paste into a server block
Frequently Asked Questions
QWhy can't I use a wildcard origin with credentials?
The browser security model prohibits using Access-Control-Allow-Origin: * together with Access-Control-Allow-Credentials: true. You must specify an explicit allowed origin when credentials are enabled.
QWhat is a pre-flight request?
A pre-flight is an HTTP OPTIONS request that browsers send automatically before certain cross-origin requests to ask the server which methods and headers it allows. Access-Control-Max-Age controls how long the browser can cache this response.
QDo I need CORS headers if my frontend and API are on the same domain?
No. CORS only applies to requests made from one origin (scheme + host + port) to a different origin. Same-origin requests bypass CORS checks entirely.
QCan I test whether my CORS headers are working after applying them?
Yes. Use the API Header Viewer or HTTP Request Tester tools on this site to fetch your endpoint and inspect the Access-Control-* headers in the response.