Header Injector

Add or override custom HTTP request headers per URL pattern.

Header Injector lets you add or override custom HTTP request headers for specific URL patterns in Chrome. Features: - Add any number of header rules, each scoped to a URL pattern - Toggle individual rules on/off without deleting them - Uses Chrome's native declarativeNetRequest API — no broad content scripts, no background network calls, no analytics - All rules are stored locally on your device and never leave your machine Built for internal development and testing workflows where you need specific headers (e.g. staging environment flags, feature toggles, auth headers for local API testing) sent only to particular hosts — without affecting normal browsing on every other site.