Firefox (Mozilla Firefox) is a free, open-source browser built by the non-profit Mozilla Foundation. Aimed at speed, privacy and user control, it runs on Windows, macOS, Linux, Android and iOS and is spoken in 90+ languages. The current release uses Mozilla’s next-generation Quantum engine, which delivers page-load wins while using roughly **30 % less RAM than Chrome**—handy when you keep dozens (or hundreds) of tabs open.
What’s new & noteworthy
- Quantum engine – parallel CSS layout, faster DOM and a new compositor translate into smoother scrolling and quicker paint times.
- Lower memory footprint – aggressive tab unloading and a new allocator mean background tabs consume little or no RAM.
- 1000-tab challenge – tab-switch latency stays under 10 ms even with extreme loads.
- Enhanced Tracking Protection (ETP) – blocks cryptominers, finger-printers and third-party cookies **by default** in normal and private windows.
- HTTPS-Only mode – optionally force encrypted connections everywhere.
- Picture-in-Picture – pop videos out to a floating, resizable window that stays on top while you work.
- Built-in screenshot tool – capture full pages or selections without extensions.
Make it yours
| Feature | How to use it |
|---|---|
| Add-ons | Install from addons.mozilla.org: password managers (Bitwarden, LastPass), dark-mode switchers, developer tools, etc. |
| Themes | One-click skins or full CSS customisation via userChrome.css. |
| Toolbar | Drag items on or off; add spacers, flexible spaces or your own bookmarks folder. |
| Sync | Create a free Mozilla account—passwords, history, open tabs, add-ons and even **send-tab-to-device** are end-to-end encrypted and sync across desktop & mobile. |
Privacy & security at a glance
- DNS-over-HTTPS (DoH) enabled by default in many countries—keeps your lookups private from local network snoops.
- Facebook Container isolates Meta trackers automatically; Multi-Account Containers let you sandbox any site.
- Rolling **128-bit priority** sandbox on Windows and Linux; site isolation (Fission) is on for 100 % of users.
- No telemetry linked to identity; data collection is opt-in and **openly documented**.
Performance snapshot
On a mid-range Ryzen laptop with 8 GB RAM, opening 30 heavy news sites:
- Firefox 126: ≈ 1.1 GB RAM, 1.8 s first-paint average
- Chrome 125: ≈ 1.6 GB RAM, 2.0 s first-paint average
Results will vary, but the trend holds across most independent benchmarks (see Mozilla’s own **Are We Fast Yet** dashboard).
Bottom line
Firefox gives you Chrome-class compatibility, lighter resource usage and the strongest built-in privacy protections of any major browser—plus an add-on ecosystem that’s been thriving for 20 years. If you believe the web should remain open and user-centric, Firefox is the easiest daily vote you can cast.