Donovan Glover

New Tab Identity

New Tab Identity is a browser extension that lets you browse the web from many different countries at the same time with Mullvad VPN.

The source code is available on GitHub.

Why New Tab Identity?

Having a browser like LibreWolf is cool, but what if you wanted to browse the web from multiple locations at once in addition to having separate cookies with fingerprint resistance?

Thanks to Firefox's Browser API support for ContextualIdentities, it's possible to proxy different tabs with different VPN locations.

Embracing convenience

By making using multiple VPN locations trivial, users are more likely to browse the web from different IP addresses.

A browser extension makes it easy to use many different VPN locations at once without having to open multiple separate browsers with different profiles like you'd have to do with Chromium's --proxy flags or Firefox's prefs.js.

How does it work?

The extension listens for new network connections in the browser and proxies them based on what container the tab is in.

The list of active VPN servers is periodically updated and users are warned when a server they're using goes offline.

How do I use it?

Changing cookies and IP addresses isn't enough to create a unique identity, therefore LibreWolf should be preferred over Firefox for its built-in fingerprint resistance.

  1. As you browse the web, open the extension popup or right click on tabs / pages / links to create new VPN containers.
  2. When you want to delete containers you're no longer using, press the X button in the extension popup.

If you use uBlock Origin (which you should), then you'll need to uncheck Uncloak canonical names in the settings to avoid leaking DNS requests.


The following permissions are used:

  • contextualIdentities: used for creating new containers
  • cookies: used for creating new containers (they have unique cookies)
  • proxy: used for proxying requests and blocking direct connections if enabled
  • storage: used for saving settings and server data
  • contextMenus: used to be able to create new containers by right clicking
  • <all_urls>: used to proxy all urls

What's the stack?

New Tab Identity is written in TypeScript and uses React for the user interface. Vite is used as the build tool and tests are written in Vitest with 100% test coverage. Nix is used for a reproducible development environment with pinned Firefox and Node.js versions.