Modify Header

Add, override, or remove request and response headers with domain-scoped rules.

Modify Header puts you in control of the HTTP headers your browser sends and receives. Whether you're debugging an API, testing a staging environment, spoofing a value your backend expects, or stripping a header a page sends back, Modify Header makes it a two‑click job — no proxy, no command line, no DevTools gymnastics. What you can do • Add or override headers — Set any request or response header to a value of your choice. • Remove headers — Strip a header from requests or responses entirely. • Scope rules precisely — Apply a rule while you're on a specific domain, to requests going to a domain, to both, or globally across all sites. • Match by URL pattern — Narrow a rule to specific paths (e.g. */api/*) using declarativeNetRequest filter syntax. • Toggle instantly — Enable or disable any individual rule, or flip a master switch to pause everything, without deleting your setup. • Manage from the toolbar — The popup shows exactly which rules apply to the page you're on and lets you add one on the spot. • Full rule manager — An options page for creating, editing, and organizing every rule, with multiple headers per rule. • Import & export — Move your rules between browsers or share them with your team as JSON. • Syncs across devices — Your rules travel with your browser profile. Who it's for Web developers, QA engineers, and API builders who need to shape headers for testing and debugging — set an Authorization token, force a User-Agent, add a X-Debug flag, drop a caching header, override Referer, and more. Built the modern way Modify Header is a Manifest V3 extension. It uses Chrome's built‑in declarativeNetRequest engine to apply your rules, so header changes happen inside the browser's networking layer — the extension never reads the content of your requests or responses. Privacy Your rules are stored in your browser and synced through your own browser account. Nothing is sent to any server operated by the developer. There is no tracking, no analytics, and no third‑party code.