Firefox
Firefox is an open-source web browser developed by Mozilla. It began as Phoenix in 2002 and released version 1.0 in 2004.
Contents14 sections
Key facts
September 23, 2002Phoenix 0.1 Released
The Mozilla project released the standalone browser Phoenix 0.1, later renamed Firefox.[1]
February 9, 2004Firefox 0.8
On February 9, 2004, Mozilla released Firefox 0.8 as a preview, changing the browser’s name from Firebird to Firefox. The preceding Phoenix 0.1 release dates to 2002; Firefox 1.0 followed in November 2004.[2]
November 9, 2004Firefox 1.0 Launch
The Mozilla Foundation released the open-source Firefox 1.0 for Windows, Mac OS X and Linux, including pop-up blocking, tabbed browsing, fraud protection and extensions.[3]
2008Firefox 3.0 Download Day
Mozilla’s retrospective says Firefox 3.0 exceeded eight million downloads in its one-day Download Day campaign, setting a Guinness World Record for software downloads in one day.[4]
2010Firefox Goes Mobile
Firefox debuted on mobile on the Nokia N900 with tabs, its address bar, sync and add-on support.[4]
November 14, 2017Firefox Quantum
Mozilla launched Firefox Quantum with a revised core engine and Photon interface; its Stylo CSS engine took advantage of multicore hardware.[5]
May 3, 2022Firefox 100
Firefox released its 100th version, adding picture-in-picture subtitles for supported sites.[6]
June 14, 2022Default Cookie Isolation
Mozilla announced default rollout of Total Cookie Protection for Firefox desktop users worldwide, separating cookies by site to limit cross-site tracking.[7]
September 1, 2026Built-In iOS Ad Blocker
Mozilla introduced a built-in Firefox iOS ad blocker using WebKit Content Blocker and EasyList. It is off by default and does not block every advertisement.[8]
October 25, 2026Come Back to Firefox Campaign
Platforms and Development
Developed by Mozilla Corporation, Firefox is available for Windows, macOS, Linux, Android and iOS. Mozilla develops Firefox as an open-source project with community contributions and provides documentation for the browser, add-ons and developer tools.[11]
Browser Engine
Firefox for desktop and Android uses Mozilla’s Gecko engine. Gecko includes web-page parsing and rendering, networking, the Document Object Model and JavaScript components; SpiderMonkey executes JavaScript. Implementations can differ between platforms.[12]
Open-source License and Trademarks
Mozilla states that Firefox software is offered under the Mozilla Public License, which permits use, copying, distribution and modification of source code under its terms. The software license does not itself grant rights to the Firefox name or logo.[13]
Sources
- Mozilla Timeline (opens in a new window)
- New round of releases extends Mozilla project’s standards based open source offerings (opens in a new window)
- Mozilla Foundation releases the highly anticipated Mozilla Firefox 1.0 web browser (opens in a new window)
- 20 years of Firefox: How a community project changed the web (opens in a new window)
- Introducing the New Firefox: Firefox Quantum (opens in a new window)
- Celebrating Firefox: How we got to 100 (opens in a new window)
- Firefox rolls out Total Cookie Protection by default to more users worldwide (opens in a new window)
- Introducing Ad Blocker for Firefox on iOS: More control, fewer distractions (opens in a new window)
- Come Back to Firefox: Mozilla launches its most ambitious campaign yet to bring people back to the independent alternative to big tech browsers (opens in a new window)
- Firefox reunites meme royalty to remind you what the internet used to feel like (opens in a new window)
- Firefox — Mozilla | MDN (opens in a new window)
- Gecko — Firefox Source Docs (opens in a new window)
- Firefox Notices (opens in a new window)