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CORS Header Builder

Network

Generate CORS headers with nginx, Express, and Apache config snippets

Fill in allowed origins, methods, and headers and get correct `Access-Control-*` response headers back, alongside ready-to-paste config snippets for Express middleware, nginx, or Apache rather than just raw header values. You still add the output to your actual server or proxy, since this tool only generates the configuration, it doesn't deploy it. Preflight OPTIONS handling is included in the generated snippets, which is easy to get wrong by hand. One subtlety worth internalizing: a wildcard `*` origin can't be combined with credentialed requests (cookies, auth headers); if you need those, you must list exact origins instead of using the wildcard shortcut. Coverage is currently nginx, Express, and Apache; other frameworks need to adapt the raw header values this tool produces to their own CORS API.

corsheadershttpaccess-control

How to use CORS Header Builder

  • 1.Fill in your allowed origins, methods, and headers to generate the correct `Access-Control-*` response headers for your API.
  • 2.Copy the generated Express middleware snippet directly into your Node.js server instead of hand-writing CORS logic.
  • 3.Switch to the nginx or Apache tab when your CORS handling lives in a reverse proxy config instead of application code.

Frequently asked questions

Does this actually configure CORS on my server?
No, it only generates the config snippet or headers — you still need to add the output to your actual server, proxy, or middleware.
What's the difference between wildcard `*` and specific origins?
A wildcard origin allows any site to make the request but cannot be combined with credentials (cookies/auth headers); if you need credentialed requests, you must specify exact origins.
Does it handle preflight (OPTIONS) requests?
Yes, the generated snippets include handling for preflight `OPTIONS` requests with the appropriate `Access-Control-Allow-Methods` and `Access-Control-Allow-Headers`.
Can I generate config for a framework other than Express?
Currently it covers nginx, Express, and Apache; for other frameworks, adapt the raw header values it generates to your framework's CORS API.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/cors-builder \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"origin":"https://example.com","methods":[],"headers":[]}'

Get an API key from your dashboard · Full API docs →

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