Firefox for Android is genuinely different from Chrome for Android in one important way: it supports WebExtensions. This means uBlock Origin, Dark Reader, Multi-Account Containers, and other extensions work on mobile — something no other mobile browser offers at scale.
Why Firefox Android is Unique
Chrome for Android doesn't support extensions. Firefox for Android runs a limited but growing subset of Firefox extensions.
Extensions available on Firefox Android (AMO):
- uBlock Origin: Full content blocking, same as desktop
- Dark Reader: Dark mode for all sites
- Multi-Account Containers: Isolated cookie jars
- Privacy Badger: Tracker blocking
- HTTPS Everywhere (archived but still works): Force HTTPS
- Bitwarden: Password manager
- 1Password: Password manager
The extension list is curated by Mozilla for mobile compatibility. Not all desktop extensions work, but the most important ones do.
Installing Firefox for Android
Standard: Download Firefox from the Play Store.
Firefox for Android (code name Fenix) — this is the main release.
Firefox Nightly for Android: Beta builds, access to experimental features.
Firefox Focus: Separate app — privacy-focused, no sync, no extensions (different value proposition).
Installing Extensions on Firefox Android
- Open Firefox Android
- Three-dot menu → Add-ons
- Browse or search available extensions
- Tap "+" to install
Or visit addons.mozilla.org from within Firefox Android — you'll see a mobile-compatible version with install options.
uBlock Origin install: The most impactful extension to install. Mobile web browsing with uBlock is significantly less cluttered than without. Many mobile sites load 2x faster with ads/trackers blocked.
Firefox Android vs Chrome Android Performance
With extensions: Firefox Android (with uBlock) often loads pages faster than Chrome Android because it blocks the tracking and ad network requests Chrome loads.
Without extensions: Chrome Android is generally faster. Chromium on Android is highly optimized for the platform.
Memory: Firefox Android historically used more RAM than Chrome. Recent versions have improved, but Chrome is still generally lighter on RAM.
Battery: With uBlock blocking network requests, Firefox may use less battery for browsing than Chrome despite slightly higher baseline overhead.
Privacy Protections
Enhanced Tracking Protection: Same as desktop — blocks trackers, social share buttons that track you, crypto miners, fingerprinting scripts.
DNS over HTTPS: Settings → Privacy and Security → DNS over HTTPS → Enabled.
Firefox Total Cookie Protection: Available on Android — cookies are partitioned per-site, preventing cross-site tracking.
Private Browsing mode: Standard — no history, no cookies kept after closing.
Firefox Sync on Android
Sign in with Firefox Account → your desktop bookmarks, passwords, and open tabs sync to Android.
Most useful sync feature on mobile: "Open tabs" — see tabs open on your desktop directly from your phone. Under Address bar → ↻ tab icon, or the Tab Count button → Other device tabs.
Cross-device search: Start typing in Firefox Android's address bar — it shows matching open tabs from your desktop. This is genuinely useful for "I was looking at this page on my computer, where was it?"
Custom URL Bar Position
Firefox Android lets you move the URL bar to the bottom (like Safari's option):
Settings → Customize → Address bar position → Bottom
For one-handed phone use, bottom bar is significantly more ergonomic on larger phones.
Reader Mode on Android
Tap the page icon in the address bar (when on an article) → switches to Reading Mode.
Reading Mode on mobile:
- Strips ads/nav/sidebars
- Adjustable text size
- Sepia/dark background
- Text-to-speech reading
For reading long articles on mobile, this is much better than the default cluttered page view.
Firefox Focus: The Companion App
Firefox Focus is separate from Firefox for Android:
- No browsing history
- Auto-erase at session end (one tap)
- Fast (no extensions, no sync, no history to load)
- Content blocking enabled by default
Use case: Quick lookups, searches, or anything you want private and temporary. The "erase" button at the bottom deletes everything instantly.
Not for daily browsing: No bookmarks (well, limited), no sync, no extensions. Pure ephemeral browsing.
Firefox for Android Configuration Worth Doing
After installing:
Set as default browser: Settings (phone) → Apps → Default apps → Browser app → Firefox
Install uBlock Origin: Three-dot → Add-ons → search uBlock Origin → install
Enable strict ETP: Settings → Privacy and Security → Enhanced Tracking Protection → Strict
Enable DoH: Settings → Privacy and Security → DNS over HTTPS
Sign in to Firefox Sync: Three-dot → Sign in to Sync
Move URL bar to bottom (optional, but recommended on large phones)
Known Limitations vs Desktop Firefox
- Extensions: More limited selection than desktop AMO
- Multi-Account Containers: Supported but container support in extensions may be limited compared to desktop
- DevTools: No DevTools on mobile (use about:debugging on desktop to remote-debug Android Firefox)
- Customization: Less about:config access (accessible but not recommended on mobile)
- Download manager: Less capable than desktop
Remote Debugging Firefox Android
Developers can debug Firefox for Android from desktop:
- Enable USB debugging on Android (Settings → Developer options → USB debugging)
- Connect phone to computer via USB
- Desktop Firefox → about:debugging → Runtime tab → "Connect" for the Android device
- Open any page in Firefox Android
- That page appears in about:debugging on desktop
- Click "Inspect" → full DevTools panel connected to the mobile browser
This is invaluable for debugging mobile-specific issues (viewport, touch events, mobile CSS).
Tab Management on Android
Firefox Android's tab management:
- Tab grid view: tap the number in the bottom bar to see open tabs
- Swipe to close individual tabs
- Tab tray at bottom
Extension option: Tree Style Tab doesn't exist for mobile, but the Sidebery team has discussed mobile plans.
Session management: Firefox Sync handles sessions across devices better than any extension. Your tabs are always available via "Other device tabs."
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