HeaderVault

Modify HTTP request and response headers with profiles and URL filters. Works locally: no network requests, no analytics.

HeaderVault lets you modify headers in your browser: add, change and remove HTTP headers of requests and responses. It is built for web developers, QA and DevOps engineers who need to send auth tokens, feature flags or debug headers, or override response headers while they test. Everything works locally. HeaderVault makes no network requests, has no analytics or telemetry, and keeps your headers in the browser's local extension storage. The code ships unminified, so anyone can read exactly what it does. Modify headers: • Set, Remove or Append any request or response header • Turn each header row on or off with one click • Several rows for the same header: the lowest row wins, Set + Append are combined for you • Invalid rows are marked next to the field and never break the others Profiles: • Keep separate header sets for staging, production or local development • Switch the active profile with one click; pause everything with one switch • Rename, duplicate, clear or delete profiles URL filters: • Limit a profile to URLs with browser URL patterns (||api.example.com^) or RE2 regular expressions • Exclude URLs and choose resource types (documents, XHR/fetch, scripts and more) Import and export: • Export all profiles or just one to a JSON file, import them on another computer • Imports profiles exported from ModHeader (JSON); every skipped setting is listed before you confirm Privacy: • Two permissions only: declarativeNetRequestWithHostAccess and storage • Site access is optional and asked for only when you enable your first header • No account, no sync, no tracking HeaderVault uses the browser's declarativeNetRequest engine, so header values are fixed text (no scripts or per-request values). Not affiliated with or endorsed by ModHeader. Privacy policy: https://headervault.com/privacy.html Support: support@headervault.com