HeaderVault

Modify request and response headers per site and per profile. Staging and QA headers never leak to other sites.

HeaderVault is a header editor built so that test headers never leak into the wrong site. QA engineers and developers add headers like Authorization, X-Feature-Flag or X-Env to reach staging builds, then forget to switch them off and the same headers follow them to production sites. HeaderVault fixes that by design: every profile is tied to the sites it may touch, and a profile with no scope cannot be turned on. How it works: - Create a profile (for example "Staging QA") and add request headers to set, append or remove. - Pick its scope: a domain (example.com also covers its subdomains), a URL prefix (for ports like http://localhost:3000/). - Switch profiles on and off from the toolbar popup. A badge shows how many profiles are active. One click pauses everything. - The Test URL box tells you exactly which profiles and headers would apply to any URL, or that none do. Built on the browser's declarativeNetRequest engine. No page scripts are injected, no traffic is intercepted by the extension itself, and no request data is ever read. Features: - Named profiles with colors and notes. - Per-profile scopes with excluded domains and resource types. - Request header set / append / remove. - Export and import profiles as JSON to share setups with your team. - Permission requested only for the exact sites you add, when you add them. - Conflict-free ordering: earlier profiles win when two set the same header. This first release is free: 3 profiles with up to 10 request headers each, domain and URL-prefix scopes, JSON export. More is planned for later updates. Privacy: all settings stay in your browser. No account, no analytics, no tracking. The extension makes no network requests. HeaderVault is an independent product and is not affiliated with ModHeader.