CORS Header Builder

Compose explicit CORS response headers for browser APIs and preflight requests.

Input stays in this browser

Build explicit CORS response headers for browser APIs and preflight requests.

Allowed origin

Avoid * when credentials are enabled.

Allowed methods

Allowed headers

Preflight cache (seconds)

Allow credentials

Response headers

Access-Control-Allow-Origin: https://app.example.com
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Headers: Content-Type, Authorization
Access-Control-Max-Age: 600

CORS is enforced by browsers; configure headers on your server or edge runtime.

How it works

Set origins, methods, request headers, credentials, and preflight caching to generate a response-header block.

Privacy

Settings stay in your browser.