CORS Header Generator is a free, browser-based tool built for developers configuring cross-origin access on an API.
Set your allowed origin, methods and headers to get the raw header values plus copy-paste server snippets.
How to use the CORS Header Generator
- Set the origin you want to allow (or * for any origin).
- List the HTTP methods and headers your API needs to expose.
- Toggle credentials on if your API uses cookies or auth headers cross-origin.
- Copy the raw headers or the Express.js / nginx snippet into your server.
Why use FreeToolsNets's CORS Header Generator?
- 100% free, with no usage limits and no account required.
- Everything runs locally in your browser — nothing you type is uploaded or stored on a server.
- Works on desktop, tablet and mobile in any modern browser.
- No installation, no plugins, and no ads blocking the tool itself.
- Part of FreeToolsNets's Developer & Data Tools collection.
Frequently asked questions
Is * safe with credentials?
No — browsers reject Access-Control-Allow-Origin: * combined with credentials; set a specific origin instead.
Does this configure my server for me?
No — it generates the header values and example snippets; you still need to add them to your actual server config.
Is this tool free to use?
Yes, completely free on FreeToolsNets, with no sign-up and no limits.
Is my data sent to a server?
No. Everything runs locally in your browser using JavaScript — nothing you enter is uploaded anywhere.
Does it work on mobile?
Yes, the widget is fully responsive and works on phones, tablets and desktops.