What can this CORS builder generate?

It builds response headers, matching Nginx directives, and a JavaScript fetch example for the selected cross-origin policy.

Why is a preflight request important?

Browsers send an OPTIONS preflight for many non-simple cross-origin requests. The generated policy includes the methods and headers needed to answer it.

Should I allow every origin with a wildcard?

Usually no. Restrict Access-Control-Allow-Origin to trusted origins, especially when credentials or private data are involved.

CORS Policy Builder

Configure cross-origin response headers and server snippets entirely in your browser

CORS configuration

Choose which origins, methods, and headers your server should allow.

Allowed origins

Enter one origin per line.

Allowed methods

Request headers

Expose headers

Allow credentials

Permit cookies and authorization credentials.

Preflight max-age (seconds)

Generated policy

Copy the format that matches your application or server.

Access-Control-Allow-Origin: https://example.com
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Headers: Content-Type, Authorization
Access-Control-Expose-Headers: 
Access-Control-Allow-Credentials: false
Access-Control-Max-Age: 86400

Privacy: your policy is generated locally. No origins, headers, or configuration data leave your browser.

About this tool

Build CORS response headers, Nginx directives, and JavaScript fetch examples for safe cross-origin requests and preflight handling CORS Policy Builder runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.

What this tool does not do

CORS Policy Builder is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.

How do I use this tool?

How do I use CORS Policy Builder?
Open CORS Policy Builder, enter or paste your input, and copy the result. The page works without an account.

CORS Policy Builder

CORS configuration

Generated policy

About this tool

What this tool does not do

How do I use this tool?

How do I use CORS Policy Builder?

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CORS configuration

Generated policy

About this tool

What this tool does not do

How do I use this tool?

How do I use CORS Policy Builder?

Related guides

CORS Explained: A Practical Guide for Web Developers

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