Azureus is a Java based BitTorrent client, with support for I2P and Tor anonymous communication protocols. It currently supports Windows, Mac OS X, Linux and Unix. Azureus was started at Sourceforge.net mostly to experiment with the Standard Widget Toolkit from Eclipse, in June 2003. It is possibly the most popular of all BitTorrent clients.

Azureus allows the user to download multiple files in a single graphical user interface (GUI). The program also features detailed statistics and a large number of user-configurable settings. While downloading a torrent, the user can view many different statistics.

Features include:

• Multiple torrent downloads

• Upload and download speed limiting, both globally and per torrent

• Advanced seeding rules

• Adjustable disk cache

• Only uses one port for all the torrents

• UPnP sets the forward on your router

• Can use a proxy, for both tracker and peer communications

• Fast resume

• Can set a default download directory and move completed files

• Can import torrents automatically from a set directory

• Highly customizable interface

• IRC plugin included for quick help

• Embedded tracker, host your own torrents, automate your shares

• Distributed Hash Table: host on it a completely decentralized torrent and/or benefit from it when the tracker is offline.