Headerly

Headerly is a fast, modern, and privacy-friendly browser extension for managing HTTP request and response headers. Whether you are debugging APIs, testing websites, switching environments, or customizing browser traffic, Headerly gives you a cleaner and more flexible way to control headers without the clutter. Why choose Headerly? Fast and reliable Built on Chrome’s Declarative Net Request API for efficient, stable header modification. Clean and intuitive experience A streamlined popup UI makes it easy to create, edit, organize, and switch profiles in seconds. Powerful profile system Use multiple profiles for different workflows such as development, testing, staging, production, or personal browsing. Flexible rule control Choose radio or checkbox modes to control how header rules are applied inside each profile. Advanced targeting Apply rules by URL, regex, domain, resource type, and request method for precise control. Easy backup and migration Import and export profiles for sharing, transferring settings, or keeping backups. Privacy-friendly by design No ads, no unnecessary complexity, and no intrusive behavior. Headerly focuses on doing one job well. Optional cookie synchronization Keep specific cookies in sync across requests when your workflow requires it. Headerly is designed for developers, testers, and power users who want a modern header management tool that is simple to use, powerful when needed, and built with privacy in mind. Open-sourced on [GitHub](https://github.com/headerly/headerly)