Firefox 4 Beta 1 is now ready to download and test! This first version gives an early look at what’s planned for Firefox 4. Stay tuned, because there is more to come and we plan to release new beta versions every two to three weeks. Your feedback is essential to help shape the product which is why we’re launching now to hear from you early in our development process.



Firefox 4 Beta 1 includes dozens of major features and improvements – by testing them early we’ll be able to respond to your feedback for future versions of Firefox. Once you download Firefox 4 Beta 1, you’re part of our beta program and will receive regular updates as more features launch.

If you are using a Windows PC, the most noticeable new feature will be the look of the browser. We moved the tabs to the top to make it easier to focus on the web content and easier to control the tools in your Web browser. Also, if you have Windows 7 or Windows Vista the Menu bar was replaced with a single Firefox button so you can get to the most used options with just one click. These changes will be coming soon for Mac and Linux.

There is a lot more to this beta than a facelift on Windows, including:
  • New Add-Ons Manager: gives you more space to manage your Add-Ons, Themes and Plugins. Customizing your browser has never been easier!
  • HD Video: Watch hardware-accelerated, super-smooth, HD-quality HTML5 video on YouTube using the new WebM format.
  • Privacy improvements: Mozilla always puts privacy first, and this latest beta fixes flaws in some Web standards that could expose your browser history.
  • Crash Protection: Experience uninterrupted browsing (now available on all platforms) – when a plugin crashes or freezes, you can resume browsing by simply refreshing the page.
  • Performance: We know that performance is important. In this version, we focused on improving responsiveness at start-up and during page loads. This is just the beginning for performance improvements in Firefox 4.
Web developers will be interested in some of the changes we’ve made under the hood:
  • HTML5 Parser: Run the best Web apps of today and tomorrow – if a user’s browser doesn’t support HTML5, they still won’t miss out on your content.
  • WebSockets: Build real-time, online interactions like gaming and chatting.
  • IndexedDB: Use structured storage in your Web applications to speed them up or provide offline support.
  • Web Console: Peek into dynamic websites with this experimental “Heads Up Display” play” analysis tool.
  • Simpler Add-On Development: Authors can create Add-Ons that don’t require a restart to install, develop their Add-Ons more quickly using the new powerful Jetpack SDK, and safely connect to existing libraries using js-ctypes.
  • For a full list of Web technologies supported by Firefox check out our “big chart o’ features.”
View: Source
Changelog: Release Notes
Download: Firefox 4 Beta 1