HeaderForge

Local-only, open-source HTTP header modifier. No ads, no telemetry, least-privilege.

HeaderForge modifies HTTP headers on the sites you choose. Built for developers, testers and security engineers who need to reshape requests without a proxy. WHAT IT DOES • Header rules: add, override or remove request and response headers, grouped into profiles you can switch with one click. • Precise scope: every rule applies only to the origins you grant. Broad host access is optional and requested by your own action, never at install. • Safety gate: rules that weaken protective headers (CSP, X-Frame-Options and the like) are flagged and require explicit confirmation before they apply. • Response mocks: replace or patch fetch/XHR responses to test edge cases without touching the backend. • Cookie editor: structured editing of the Cookie header instead of hand-typed strings. • Import/export: share profiles as files; imported files are validated and dangerous rules are re-confirmed. PRIVATE BY DESIGN No account, no server, no analytics. Your configuration lives in your browser and nowhere else. The code is open source (MIT).