Headers, your way
Add, modify, remove, or append request and response headers. Scope rules by URL pattern or resource type.
ModHeaderX
Browser extension for developers
Your browser traffic. Under your control.
Modify request and response headers, organize rules into profiles, and inspect HTTP requests and WebSocket traffic. Built for Chrome and Firefox.
- Chrome
- Firefox
Inspect the full-size screenshot (opens in a new tab)Thoughtfully built
What makes it yours.
Profiles for every workflow
Create, clone, and reorder profiles. Pause modifications globally or lock them to the current tab.
Inspect patched requests
Record HTTP traffic on demand, filter by resource type, inspect headers and bodies, and copy a request as cURL.
Look inside WebSockets
Inspect connection state, handshake headers, and observed messages with Text, JSON, Hex, Base64, and MessagePack views.
Move your setup with you
Export and import profiles as JSON, or back them up and restore them with browser sync.
Session-only inspection
Request and WebSocket recording is opt-in. Captured traffic stays in the session and is not included in profile exports.
Inside ModHeaderX
See it in action.
Scroll to explore. Select any screen to inspect it at full size.
Inspect the full-size screenshot (opens in a new tab)
Inspect the full-size screenshot (opens in a new tab)ModHeaderX