Header Editor - Modify Request & Response Headers

Modify request headers, response headers and redirect URLs, with rules isolated per site.

Header Editor modifies HTTP request headers, response headers and redirect URLs — with one key difference: every rule lives in a profile that is scoped to a single site, so rules for one domain never leak into another. FEATURES • Request headers — set, append or remove any header (Authorization, User-Agent, custom X-* headers, …) • Response headers — e.g. add Access-Control-Allow-Origin for local development, strip Content-Security-Policy while debugging • Redirect URLs — wildcard patterns or RE2 regex with \1–\9 capture groups (e.g. rewrite /v1/(.*) to /v2/\1) • Per-site isolation — each profile is scoped to a domain (subdomains included) or a URL pattern; leave the scope empty to apply everywhere • Three-level switches — master pause, per-profile, per-rule • Toolbar badge shows the number of active rules; invalid rules (e.g. a bad regex) are reported in the popup instead of failing silently • Duplicate profiles, export them as JSON BUILT ON MANIFEST V3 Header Editor uses Chrome's declarativeNetRequest API: headers are rewritten by the browser's network layer. No content scripts are injected into pages, nothing slows your browsing down, and the extension cannot read the traffic it modifies. PRIVACY All data stays in your browser's local storage. Header Editor collects nothing, transmits nothing, and talks to no server.