Firefox 1

Firefox 1 (en-US) 21.0

Legacy version of Firefox that's no longer supported

WARNING: This is a very old version of Firefox. View full description


WARNING: This is a very old version of Firefox.

To download the most recent stable release, click here.

We'll leave this one up for a while in case advanced users would like to download it for other purposes!

Mozilla Firefox is a fast, full-featured browser for Windows that makes browsing more efficient than ever before. It offers a complete set of features to give you a truly user-friendly experience.Firefox has quickly become the reference in alternative web browsers.

Here are its main features:

Popup blocking

Stop annoying popup ads in their tracks with Firefox's built in popup blocker

Tabbed browsing

View more than one web page in a single window with this time saving feature. Open links in the background so that they're ready for viewing when you're ready to read them.

Privacy and security

Built with your security in mind, Firefox keeps your computer safe from malicious spyware by not loading harmful ActiveX controls. A comprehensive set of privacy tools keep your online activity your business.

Smarter search

Google Search is built right into the toolbar, and there is a plethora of other search tools including Smart Keywords (type "dict " in the Location bar), and the new Find bar (which finds text as you type without covering up anything).

Live bookmarks

RSS integration lets you read the latest news headlines and read updates to your favorite sites that are syndicated.

Hassle-free downloading

Files you download are automatically saved to your Desktop so they're easy to find. Fewer prompts mean files download quicker.

Fits like a glove

Simple and intuitive, yet fully featured, Firefox has all the functions you're used to - Bookmarks, History, Full Screen, Text Zooming to make pages with small text easier to read, etc.

S, M, L or XL—it's your choice

Firefox is the most customizable browser on the planet. Customize your toolbars to add additional buttons, install new Extensions that add new features, add new Themes to browse with style, and use the adaptive search system to allow you to search an infinite number of engines. Firefox is as big or small as you want.

Setup's a snap

At only 4.7MB (Windows), Firefox takes just a few minutes to download over a slow connection and seconds over a fast connection. The installer gets you set up quickly, and the new Easy Transition system imports all of your settings - Favorites, passwords and other data from Internet Explorer and other browsers - so you can start surfing right away.

A developer's best friend

Firefox comes with a standard set of developer tools including a powerful JavaScript and CSS error/warning console, and an optional Document Inspector that gives detailed insight about your pages.

Firefox 1


Firefox 1 (en-US) 21.0

— User reviews — about Firefox 1

  • CygnusCentauri

    by CygnusCentauri


    Just an outdated version of Firefox. Try the latest version if you want the best. More.

    reviewed on December 10, 2015

  • RobertAlfon

    by RobertAlfon

    "Best browser of all."

    I like it alot, it's fast, reliable, and secure. It shows all websites properly, unlike any other internet browser. More.

    reviewed on February 23, 2012

  • smurray

    by smurray


    Whatever Microsoft do with the next version of IE, there´s no way it´s going to come close to FF. Apparently Microsoft h... More.

    reviewed on October 31, 2005