CORS Header Generator
Generate CORS headers configuration
CORS Header Generator is a free online tool from BrowserUtils that generate cors headers configuration. It runs entirely in your browser — your data never leaves your device. No account required.
How to use CORS Header Generator
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About CORS Header Generator
Free online CORS header generator. Generate Access-Control-Allow-Origin and other CORS headers for your API. Get configuration for Express, Nginx, Apache, and more. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
CORS Header Generator specs
- Runtime
- 100% client-side (browser)
- Built on
- WHATWG URL API and Headers/Fetch standards as implemented by modern browsers
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
What is CORS?
CORS (Cross-Origin Resource Sharing) is a security mechanism that allows web applications on one domain to request resources from another domain. It uses HTTP headers to tell browsers which cross-origin requests should be permitted.
What is the Access-Control-Allow-Origin header?
The Access-Control-Allow-Origin header specifies which origins are allowed to access the resource. It can be set to a specific origin (e.g., https://example.com), or * to allow any origin (not recommended for credentialed requests).
What is a CORS preflight request?
A preflight request is an OPTIONS request the browser sends automatically before certain cross-origin requests (like those with custom headers or non-simple methods). The server must respond with the appropriate CORS headers to allow the actual request to proceed.
What server configurations does the CORS generator output?
The generator produces CORS header configurations for Express.js, Nginx, Apache (.htaccess), and raw HTTP headers, so you can copy the snippet directly into your server setup.
Is it safe to set Access-Control-Allow-Origin to *?
Using * allows any website to make requests to your API, which is fine for public APIs. For APIs that use cookies or authentication tokens, you must specify exact origins instead of * to prevent security risks.
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