Header Master

About

Header Master — Short Store Description

Modify outgoing HTTP request headers for web testing, API debugging, and Quality Assurance workflows.

Header Master is a Manifest V3 developer extension that lets users create, manage, and apply custom request headers directly in the browser. Configure domain-based rules, use dynamic variables, and control header conflicts with overwrite, append, or bypass modes.

Designed for developers, QA teams, backend engineers, staging environments, feature flag testing, localization testing, and request tracing.

 Features

1.Add, edit, enable, and disable custom headers
2. Apply headers using Manifest V3 network rules
3. Scope rules to selected domains
4. Support dynamic variables
5. Master on/off switch
6. Local-only storage with no external accounts or analytics

Permissions

declarativeNetRequest — Modify outgoing request headers
declarativeNetRequestWithHostAccess — Apply rules to selected websites
storage — Save local extension settings and header rules
Privacy

 No accounts required
 No remote analytics
 No data sent to external servers
 All configuration stored locally in the browser