Custom Header

Easily add, manage, and inject custom HTTP headers into every browser request. A lightweight and elegant alternative to ModHeader.

Custom Header lets you add custom HTTP headers to every network request directly from your browser — perfect for developers, QA engineers, and API testers. Features: - Add unlimited custom request headers (key-value pairs) - Toggle individual headers on/off instantly - Master toggle to enable/disable all headers at once - Headers persist across browser sessions - Works on all network requests (XHR, fetch, images, scripts, etc.) - Clean, modern dark UI - Lightweight — no bloat, no tracking, no permissions beyond what's needed Use cases: - Add Authorization or API key headers for testing - Simulate custom client headers for debugging - Inject X-Forwarded-For or other proxy headers - Override Accept-Language or Content-Type headers Built with Manifest V3 and the declarativeNetRequest API for maximum performance and security.