ModHeader v3

ModHeader: Modify HTTP request & response headers, cookies, redirects, and CSP. All data stays on your device.

**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.