Firefox
Mozilla's independent Gecko browser with strong customization, privacy controls, and a separate extension ecosystem.
Published by Mozilla (United States) · Verified
Runs on
- macOSmacOS: Available
- WindowsWindows: Available
- LinuxLinux: Available
- AndroidAndroid: Available
- iOSiOS: Available
Choose it when
Choose Firefox when engine independence, a mature privacy control set, and the Firefox Add-ons ecosystem are priorities.
Avoid it when
Avoid it if a site or enterprise workflow is tested only against Chromium or if Chrome-only extensions are essential.
Quick answers
Read straight off the verified record - every one of these is expanded with its source below.
- Which platforms does Firefox run on?
- Documented on macOS, Windows, Linux, Android, and iOS.
- Can I install Chrome extensions?
- No - the Chrome Web Store is not supported.
- Does it block trackers out of the box?
- Yes - tracker or ad blocking is on by default. Enhanced Tracking Protection blocks known trackers by default.
- Does it have built-in AI features?
- Yes - 5 of 9 documented AI capabilities are built in.
- Is it open source?
- Open source under Mozilla Public License 2.0 and compatible licenses
- Is it still being developed?
- Active - Actively developed by Mozilla across desktop and mobile platforms.
What Firefox does
Open any row for the wording and the source behind it
Privacy and tracking
4 built in
Blocks trackers by defaultBlocks trackers by default: Built in
Enhanced Tracking Protection blocks known trackers by default.
Anti-fingerprintingAnti-fingerprinting: Built in
Enhanced Tracking Protection includes fingerprinting protection controls.
Telemetry postureTelemetry posture: Built in
Firefox offers telemetry and data-collection controls in settings.
Built-in VPN or proxyBuilt-in VPN or proxy: Built in
A built-in browser VPN is rolling out regionally; Mozilla VPN remains a separate paid full-device service.
Private windowsPrivate Windows discard local history and use stricter tracking protections; they are not anonymous browsing.
Private Windows discard local history and use stricter tracking protections; they are not anonymous browsing.
- Default search engineGoogle
Extensions and blocking
4 built in · 1 not available
- Chrome Web StoreChrome Web Store: Unsupported
- Firefox Add-onsFirefox Add-ons: Supported
Native content blockingNative content blocking: Built in
Enhanced Tracking Protection is native but is not equivalent to a universal ad-blocking promise.
Manifest V3Manifest V3: Built in
Firefox supports Manifest V3 with browser-specific API differences.
Manifest V2Manifest V2: Built in
Firefox continues to document WebExtensions APIs with its own compatibility policy.
Known limitationsChrome extensions are not a supported installation path; Firefox Add-ons compatibility is the relevant measure.
Chrome extensions are not a supported installation path; Firefox Add-ons compatibility is the relevant measure.
Workflow
7 built in · 2 partial · 2 not available
Vertical tabsVertical tabs: Built in
Vertical tabs are a built-in layout option, enabled from the tab strip or sidebar settings.
- Tab treesTab trees: Unavailable
- Workspaces or spacesWorkspaces or spaces: Unavailable
ProfilesProfiles: Built in
Profiles or equivalent browser identities are available.
Split viewSplit view: Built in
A native Split View shipped in Firefox 149.
SidebarSidebar: Built in
Firefox includes a sidebar for bookmarks, history, and tabs.
Reader modeReader mode: Built in
Reader View is built in.
Command paletteCommand palette: Available by extension
Command palettes are available through add-ons.
Sync across devicesSync across devices: Built in
Sync is provided by the browser or its upstream project.
TranslationTranslation: Built in
Firefox Translation is available for supported language pairs.
Progressive web appsProgressive web apps: Minimal or opt-in
Native taskbar web apps are Windows-only since Firefox 143; other desktops need an extension.
AI features
5 built in · 1 partial · 1 not available · 2 undocumented
Built-in assistantBuilt-in assistant: Built in
AI chatbot sidebar and AI Controls provides a built-in assistant surface.
Page summarisationPage summarisation: Built in
AI chatbot sidebar and AI Controls documents page or multi-tab summarisation.
Acts on pages for youActs on pages for you: Unavailable
Agentic actions are not documented.
AI answer engineAI answer engine: Minimal or opt-in
Smart Window, documented as a beta, provides AI answers with live web results and cited sources.
Works across open tabsWorks across open tabs: Built in
AI chatbot sidebar and AI Controls documents awareness of multiple tabs or history.
Text or image generationText or image generation: Unknown
Generation features are not documented.
Choice of modelChoice of model: Built in
AI chatbot sidebar and AI Controls documents a choice of models or local model support.
Retention or training controlsRetention or training controls: Built in
AI chatbot sidebar and AI Controls documents retention, training or kill-switch controls.
Voice or image inputVoice or image input: Unknown
Voice or image interaction is not documented.
On a phone
5 built in · 5 undocumented
Undocumented is not the same as absent - it means the publisher does not state it.
Extensions on mobileExtensions on mobile: Built in
Add-ons install on Android from addons.mozilla.org through an in-app extensions manager; Mozilla states add-ons are unavailable on iOS.
Can be the phone defaultCan be the phone default: Built in
Mozilla documents the steps to make Firefox the default browser on both Android and iOS.
Biometric lockBiometric lock: Built in
Android private tabs can be locked behind face, fingerprint, or PIN.
Offline readingOffline reading: Unknown
Reader View is documented; saving a page to read offline is not.
Desktop-site modeDesktop-site mode: Built in
Switching a page to desktop view is documented for both mobile builds.
Download managerDownload manager: Built in
Android documents a Downloads screen; the iOS pages cover saving files without naming a manager.
Background playbackBackground playback: Unknown
Background or picture-in-picture playback is not documented.
Web pushWeb push: Unknown
Web push support is not documented.
- Data saverData saver: Unknown
Address-bar placementAddress-bar placement: Unknown
Address-bar placement is not documented.
Under the hood
- Rendering engine
- Gecko
- JavaScript engine
- SpiderMonkey
- Upstream project
- Mozilla Firefox
- Release channel
- stable
- Code and licence
- Open source under Mozilla Public License 2.0 and compatible licenses
- Install method
- Official installer, Linux package, or app store.
- Hardware support
- Official desktop builds cover common 64-bit architectures.
Active. Actively developed by Mozilla across desktop and mobile platforms.
Editorial view
Firefox is the only mainstream browser that is not a Chromium distribution, and that single fact carries most of the argument for it. Gecko and SpiderMonkey are an independent engine lineage, open source under the Mozilla Public License, with official builds for macOS, Windows, Linux, Android, and iOS. The iOS app renders with WebKit like every iPhone browser, so engine independence is a desktop and Android story.
Privacy: better defaults, honest limits
The defaults beat Chrome's without reaching the fork extremes.
- Enhanced Tracking Protection blocks known trackers out of the box, with fingerprinting controls included.
- Telemetry exists but has real settings.
- A built-in browser VPN is rolling out by region, separate from the paid full-device Mozilla VPN.
- Private Windows drop local history and tighten protections, and they still do not make you anonymous.
Search defaults to Google, which quietly funds a large share of Mozilla, an arrangement worth knowing about when you weigh the independence argument.
The extension trade
Firefox Add-ons is a separate ecosystem, Chrome extensions do not install, and both Manifest V2 and V3 remain supported under Mozilla's own policy. In practice that means uBlock Origin keeps working here at full strength, and it also means any Chrome-only tool needs a replacement before you switch. On Android, Firefox installs real add-ons, including content blockers, which no mainstream Chromium browser matches.
Workflow, no longer an apology
Vertical tabs are native now, a right-click on the tab strip away. Split View arrived in Firefox 149. The sidebar, Reader View, sync, and translation are built in. Command palettes still need an add-on, and native web-app installs only exist on Windows so far.
The verdict
Choose Firefox for engine diversity, strong defaults you can actually configure, and mobile extensions. Avoid it when a site or enterprise workflow is only tested against Chromium, or when one Chrome-only extension is non-negotiable. If you switch, move bookmarks and passwords first, then rebuild the extension set deliberately rather than hunting one-to-one equivalents, because the good Firefox setup is usually a shorter list. Organisations that want fewer changes can also use Mozilla's ESR channel, which batches feature updates while keeping security fixes current.
Where these facts come from
Every capability above is read from a primary source and dated. 0 of 30 fields stay recorded as unknown rather than assumed.
- Firefox official product pageVerified
Product and platform scope.
Alternatives to Firefox
- LibreWolfLibreWolf contributorsGeckoActive
A Firefox derivative with privacy-hardening defaults and reduced Mozilla service integration.
View profile - BraveBrave SoftwareChromiumActive
A Chromium browser with native Shields blocking, optional privacy services, and Chrome extension compatibility.
View profile - FloorpFloorp ProjectsGeckoActive
A Firefox-based browser with vertical tabs, workspaces, sidebars, and customization for power users.
View profile
Reviewed comparisons featuring Firefox
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