ModHeader v3

About

**Modify HTTP Headers, Response Headers, Cookies, Redirects & Content Security Policy (CSP) — 100% Local & Offline**

Take complete control over your web traffic with a fast, privacy-focused header modification tool that runs entirely on your device. Modify **HTTP request headers**, **HTTP response headers**, **cookies**, **URL redirects**, and **Content-Security-Policy (CSP)** rules using customizable profiles for development, testing, debugging, and security research.

Unlike cloud-based alternatives, all configuration, rules, and profiles are stored **locally on your computer**. No data is collected, transmitted, or uploaded to external servers. The extension works completely **offline**, ensuring maximum privacy, security, and performance.

### Features

* Modify HTTP request headers in real time.
* Edit HTTP response headers before they reach the browser.
* Add, remove, or rewrite cookies.
* Create custom URL redirect rules.
* Override or modify Content-Security-Policy (CSP) headers.
* Organize rules into reusable profiles.
* Enable or disable profiles instantly.
* Works entirely offline with no internet dependency.
* No tracking, analytics, telemetry, or data collection.
* All data remains on your device for complete privacy.

Perfect for **web developers**, **API testing**, **browser debugging**, **QA engineers**, **security testing**, and **local development** workflows that require precise control over HTTP traffic without sacrificing privacy.