Headerlane: HTTP header editor

Headerlane sets, changes or removes the HTTP headers your browser sends, for the sites you choose. Add an Authorization token for your staging API, a feature flag for localhost, or a mobile User-Agent, and switch each one on or off in a click. Moving from ModHeader, which was removed from the Chrome Web Store in July 2026? Import its exported profiles in one step. What it does for free • Request header rules per URL pattern: a host like api.example.com, a path, or a regular expression. Set a header or remove it. • A switch on every rule and every header, and Pause all to turn everything off at once. • The toolbar icon shows how many rules apply on the tab you're on, and its popup lists them so you can switch one off. • Imports a header-editor export file and exports your rules as JSON, so you can copy them to another browser. There's no sync server; the file is the sync. Pro, one payment for up to 3 browsers • Profiles: keep staging, prod debug and local setups apart and switch in one click, or with Alt+Shift+P. • Response headers: change what the server sends back, such as CORS headers for local testing. • Redirects: send a request somewhere else before it leaves the browser, such as production JavaScript to localhost. Every Pro feature is on free for the first 3 days after install, with no card or email. When the trial ends, Pro rules pause; nothing you made is deleted. Private by design • No analytics, no ads, no remote config. • Chrome applies your rules itself. Headerlane never sees your requests or their contents. • Site access is asked for one site at a time, when you add a rule for it. Never "all sites" at install. • Your rules stay in this browser. The only request Headerlane makes is the Pro license check with Lemon Squeezy, who sells it. Clicking Buy opens our site, and Chrome opens a short feedback page there if you uninstall. Honest limits • Works in Chrome 121 and later on a computer. • Chrome lets an extension have up to 1,000 pattern rules, so that's the most Headerlane can apply at once. • It can't return a made-up response body (a mock); Chrome's extension API doesn't allow it. • Chrome doesn't let extensions change requests on chrome:// pages or the Chrome Web Store. Headerlane is made by AISS SOFTWARE and isn't affiliated with or endorsed by Google. Help: hello@aisssoftware.com · https://aisssoftware.com/headerlane