ModHeader 4U

ModHeader 4U is a Chrome extension that allows you to modify HTTP headers and response bodies.

Tired of bloated header utilities packed with unwanted tracking scripts and pop-up ads? Welcome to a cleaner alternative. This extension is a lightweight, open-source tool built strictly with modern Manifest V3 standards to give developers full control over their HTTP request headers without compromising security. It is completely free, completely ad-free, and runs entirely locally on your machine. Why use this extension? 100% Safe & Private: Built natively using Chrome's declarativeNetRequest API. It does not monitor your browsing background history, execute remote code (eval), or call home to external servers. Your configurations never leave your device. Completely Free & Ad-Free: Zero telemetry, zero unexpected redirects, and zero corporate bloat. Just a clean dashboard utility built for developers, by developers. Persistent Sidebar Layout: Utilizes the native Chrome Side Panel API so your configuration dashboard stays open persistently and resizes beautifully as you jump across local tabs and dev environments. Effortless Profile Synchronization: Easily configure, toggle, and manage complex header sets for your custom web hooks, authentication tokens, and API endpoints. Perfect for: Debugging local microservices, bypassing CORS restrictions during local development, mimicking specific user agents, and verifying secure request layers. Clean code. Fast performance. No malware.