Header Editor

An extension which can modify the request, include request headers, response headers, response body, redirect requests, and cancel requests.

It's 100% FREE, no ADs, no data collection.

Visit he.firefoxcn.net for more documentations.

Get this extension

• The official download is exactly the same as Mozilla Add-ons, but the Mozilla Add-ons review is very slow, usually taking more than a week, and you may not be able to get the latest version.
• HeaderEditor-xxx-v2 is full version, HeaderEditor-xxx-v3 is lite version.
• Diff between lite and full version

Permissions

Header Editor require those permissions:

• tabs: Open links (such as the options page)

• webRequest, webRequestBlocking, declarativeNetRequest, *://*/*: Modify requests

• storage, unlimitedStorage: Storage rules and settings

• debugger: Modify response body in Chrome

• unsafe-eval: Execute custom function, code at src/share/core/rule-utils.ts#L41 (may change in the future, you can search for the newest location by new Function)

Contribution

Contribute codes: Submitting a pull request

Thanks to them for their contribution: YFdyh000 iNaru hzfi ghcsd

Translation

English: Please submit a issue or pull request to file locale/original/messages.json

Other language: Please translate them on Transifex

Please note that some languages (such as zh-Hans) will not be translated on transifex because the browser does not support them, view full list.

How to build

Build

• Install Node.js 24.x and pnpm 11.x.
• Clone this project, or download the source code and extract it.
• Run pnpm i --frozen-lockfile.
• Run build command
  • For chrome full version, run npm run build:chrome_v2
  • For chrome lite version, run npm run build:chrome_v3
  • For firefox full version, run npm run build:firefox_v2
  • For firefox lite version, run npm run build:firefox_v3
• Find build result at /dist_*

Development

• Modify start command's TARGET_BROWSER to the version you want to build
• Run npm run start
• Open browser, load extension from /dist_* directory or /dist_*/manifest.json

Licenses

Copyright © 2017-2026 FirefoxBar Team

This project is licensed under the ​GNU GPL v2.0 or later. Unauthorized use for training, imitation, learning, generation, or related activities in the field of artificial intelligence (AI) is prohibited.

Technical Sponsorship

CDN acceleration and security protection for this project are sponsored by Tencent EdgeOne.