When Opera Software launched Turbo, it was one of a kind service that users of the browser -- desktop and mobile -- could make use of to tunnel traffic through Opera servers to reduce the bandwidth needed to download the data.
This was done by compressing data before sending it to the user. Google later on introduced a data compression proxy for mobile clients of Chrome, and Opera launched a standalone client called Opera Max for Android as well.
Mozilla has been working on project Janus for some time without revealing much about it to the public. The goal of the project is to improve the browsing experience of the user. Here it is mobile users that Janus is targeting mainly but desktop users will gain access to the same technology as well.
The official wiki entry lists the goals of the project:
- Reduce page load times
- Reduce bandwidth requirements
- Increase user privacy
- Increase responsiveness for slow sites.
- Reduce radio time.
Like Opera Turbo and Max, and Google's Off-Road modus, it is making use of a proxy server that sits between the user's device and the Internet.
Traffic flows through the proxy server, and several methods are used to ensure that the goals listed above are met.
Among other things, this includes compressing images, text and certain types of streams, utilizing caching technologies, or reducing HTTPS round trips.
Mozilla notes that compression should not have an impact on the visual quality of the image. This means that it will work well on images that are not optimized, while you may not see a large difference in size when it comes to images that have been optimized by the webmaster.
The majority of features up until now are similar to other proxy technologies. Mozilla has additional ideas on how to improve it further. This includes
converting gifs to videos to reduce their size, entering readability mode automatically for some sites, ad blocking, Opera Mini-like pre-rendering of pages, and adding support for adaptive-streaming (some items are already implemented, see update below).
Try it out right now
Mozilla has released an add-on that Firefox users can install to try out the proxy right now. It is only compatible with Firefox 33 and newer versions of the browser which means that only Aurora or Nightly users can install the proxy at the time of writing. The mobile version of the add-on is compatible with all versions of the Firefox browser from 32 on.
All you need to do is install the add-on. The proxy is automatically enabled and will improve the browsing in the ways mentioned above.
You can click on the icon to display information about traffic and the bandwidth savings. Here you can also disable the proxy.
The proxy seems to work only on http websites at the time of writing and not on https sites.
Update: you can enable ad blocking and gif to video conversions in the program options. Here you can also switch from bandwidth saving to low latency optimizations instead.
Janus is a very interesting project, not only for mobile versions of Firefox but desktop versions as well. While mobile users may benefit the most from it on average, as their connection speeds are usually lower and less reliable than on desktops, it may improve browsing all across the board thanks to the features that it offers.
On top of the speed benefits, it is also improving user privacy in a number of ways. Since you are connecting to the proxy, it is the proxy's IP address that servers on the Internet interact with.
This could be a game changer for Mozilla if implement and marketed correctly.