About — HeaderForge

What it is

HeaderForge is a Chrome extension for modifying HTTP request and response headers, plus request cookies. It's aimed at developers, QA engineers, and anyone who needs to test how a site behaves under different headers without standing up a proxy or changing server code.

It's built on Chrome's modern declarativeNetRequest engine, which means Chrome itself performs the header changes from rules the extension registers — the extension never reads the content of your requests or the pages you visit.

🇺🇸 Made in the USA

Designed and maintained by an independent developer in the United States.

🔒 Local-first by design

No server, no analytics, no telemetry. Your rules and profiles live only in your browser.

∞ Always free

No accounts, no paywalls, no "pro" tier. Free today and meant to stay that way.

🧩 Chrome only, for now

Available for Google Chrome at the moment, on any OS Chrome supports.

License & free-software agreement

HeaderForge is released under the MIT License — one of the most permissive open-source licenses. In plain terms: you're free to use it for anything, including at work, study how it functions, modify it, and share it. It comes with no warranty, and the copyright notice must be kept with copies.

MIT License Copyright (c) 2026 HeaderForge App Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Privacy

HeaderForge collects nothing and transmits nothing. There is no account to create and no data to leak, because there's no server on the other end. Anything you configure — including sensitive values like tokens — is stored locally in your browser and is sent only to the sites your own rules target. For the full statement, see the privacy policy shipped with the extension.

Contact

Questions or anything else — reach out:

✉️ contact [at] headerforgeapp [dot] com

Suggestions & kudos

Have an idea, hit a bug, or just want to say thanks? Pick one — it opens a pre-addressed email, no account needed.

💡 Send a suggestion ⭐ Say thanks 🐞 Report a bug

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