SimpleModHeader

A fast, open-source HTTP header modifier for developers. Add, edit, and toggle request & response headers with ease. Privacy-first, lightweight, and completely free. Detailed Description SimpleModHeader is a lightweight, open-source Chrome extension that lets developers modify HTTP request and response headers quickly and securely. Built as a transparent, privacy-focused alternative after ModHeader was removed from the Chrome Web Store for injecting malicious code, SimpleModHeader gives you the features you need—without tracking, telemetry, or unnecessary bloat. 🚀 Features 1. Request & Response Headers Add, edit, remove, or override any HTTP request or response header. Perfect for debugging APIs, testing CORS, injecting authorization tokens, or simulating different environments. 2. Profiles Create multiple header profiles for Development, Staging, Production, or any workflow. Switch between them instantly with a single click. 3. URL Filtering Apply headers only to specific URLs using pattern matching. Target your API endpoints without affecting the rest of your browsing. 4. Import & Export Export your header configurations as JSON and easily share them with teammates. Import existing configurations in seconds. 5. Drag & Drop Reordering Reorder headers with an intuitive drag-and-drop interface to keep configurations organized. 6. Duplicate Headers Clone existing header entries with one click instead of recreating similar configurations manually. 7. Per-Header Toggle Enable or disable individual headers without deleting them. Use the master toggle to disable all modifications instantly. 🔒 Privacy & Security Privacy is a core design principle. • No external network requests—nothing leaves your browser. • No analytics, telemetry, or tracking. • No content scripts injected into web pages. • Uses Chrome's Declarative Net Request API, so the extension never reads your request or response data. • Fully open source—inspect every line of code on GitHub: github.com/…/simplemodheader 💡 Common Use Cases Debug API requests by adding Authorization or custom headers. Test CORS behavior during local development. Enable or disable feature flags using custom headers. Simulate different clients or user agents. Override Content Security Policy (CSP) headers for testing. Add tracing or debugging headers for backend services. Test APIs across development, staging, and production environments. ⚡ Built for Developers Open source Chrome Manifest V3 Built with vanilla JavaScript Zero runtime dependencies Fast, lightweight, and privacy-first Whether you're debugging APIs, testing backend services, or working with multiple environments, SimpleModHeader provides a clean, secure, and reliable way to modify HTTP headers without compromising your privacy.