Firefox vs Zen Browser

Firefox

• People who want tracker blocking switched on by default
• Users who prefer an open-source browser that is not based on Chromium
• Those who want to pick their own AI chatbot, or turn AI off
• Anyone moving between Windows, macOS, Linux and a phone

Zen Browser

• People who prefer vertical tabs and a minimal interface
• Firefox users who want workspaces and split view built in
• Those who want an open-source browser funded by donations

Firefox

• The built-in VPN is capped at 50 GB per month and protects browser traffic only. Mozilla's paid VPN service costs $59.88 per year or $9.99 per month, plus tax.
• Firefox shows optional ads on its homepage to fund development. They can be turned off.
• The built-in VPN has not reached Firefox for Android or iOS; Mozilla's roadmap lists VPN on mobile as upcoming work.
• Windows 8.1 and below and macOS 10.14 and below are no longer supported by the standard release; they need Firefox ESR.

Zen Browser

• Zen is labeled a beta and is maintained by a small team, so bug reports and feature requests can take time.
• There is no Android or iOS version, and the FAQ says none is planned.
• The FAQ says Zen has no Widevine license, so DRM-protected streaming does not play on Windows or macOS.
• Horizontal tabs are not supported; the team says they will not be added in the near future.

Firefox

Tracking and cookie protection

Enhanced Tracking Protection blocks known trackers by default, and Total Cookie Protection keeps each site's cookies separate. The shield icon in the address bar shows what was blocked.

Built-in VPN

A VPN toggle in the desktop toolbar routes browser traffic through a proxy server to hide the IP address, free for up to 50 GB per month. It covers the browser only, not other apps on the device.

Tab groups, vertical tabs and sidebar

Tabs can be grouped and color coded or stacked vertically, and a customizable sidebar gives one-click access to bookmarks, history, synced tabs and other tools.

AI chatbots in the sidebar

The sidebar can host a third-party assistant such as ChatGPT, Gemini, Copilot, Claude or Mistral Chat. AI features are optional and can be turned off entirely.

Sync with a Mozilla account

Bookmarks, history, saved passwords and open tabs sync across desktop and mobile with end-to-end encryption, and Send Tab pushes a page from one device to another.

Reader mode, PDF editor and translation

Reader mode strips clutter from articles, a built-in editor fills, signs and annotates PDFs, and pages are translated in the browser without sharing the data with anyone else.

Zen Browser

Workspaces

Tabs are organized into Workspaces so that separate projects stay apart, with quick switching from one to another.

Vertical tabs and Compact Mode

The whole interface is built around a vertical tab bar. Compact Mode hides that bar until it is needed, leaving more of the screen for the page.

Split View

Split View shows tabs side by side for comparison. Tabs are selected with Ctrl or Shift and split from the right-click menu.

Glance

Glance gives quick access to the tabs a person uses most, without scrolling back through history to find them.

Zen Mods

Zen Mods are themes and modifications that change how the browser looks and behaves, and the documentation covers live CSS editing for further customization.

Sync through Firefox Sync

Signing in with a Mozilla account syncs add-ons, bookmarks, history, passwords and other browser data across devices.

Firefox

• Free$0

  The full browser on Windows, macOS, Linux, Android and iOS, including tracker blocking, sync and, on desktop, the built-in VPN up to 50 GB a month.

Zen Browser

• Free$0

  The full browser for macOS, Windows and Linux, including Workspaces, Split View, Compact Mode and Zen Mods.