xHeader - Modify HTTP headers

A modern ModHeader alternative for modifying request headers and response headers with profiles, filters, tab targeting, and sync.

xHeader is a modern ModHeader alternative that makes it easy to modify HTTP request and response headers directly from a compact browser popup. Create reusable profiles for different projects, environments, or testing scenarios. Click a profile to make it active, or pause it instantly from the toolbar. xHeader applies only the header changes and filters you configure. Key features: - 📤 Modify request headers and response headers - 🛠️ Set, append, or remove headers - 🎨 Create color-coded profiles - 🔍 Search names, values, and filters - ✨ Autocomplete common headers and values - 🌐 Filter by request or tab domain - 📌 Target tabs and tab groups - 🔢 See active filter counts - ↩️ Undo and redo changes - 🔄 Sync profiles with Chrome - 💾 Import and export JSON - 🌙 Switch between light and dark mode - 🖥️ Edit in the popup or a full tab - ↔️ Collapse the profile sidebar Advanced features, including filters and enabling multiple profiles at the same time, require App Pass activation. Core request and response header editing remains easy to access from the popup. xHeader is useful for web development, API testing, debugging, CORS experiments, localization testing, staging environments, and any workflow that needs repeatable HTTP header changes. Use header modifications carefully. Incorrect request or response headers can change how websites behave.