uTorrent

BitTorrent client for Windows, macOS, Linux (web interface) and Android, written in C++ and featuring a small size and high speed with a fairly large functionality. In January 2011, the number of users per month reached 100 million (shared with BitTorrent).

μTorrent, or uTorrent (see pronunciation) is a proprietary adware BitTorrent client owned and developed by Rainberry, Inc. with over 150 million users. It is the most widely used BitTorrent client outside China; globally only behind Xunlei. The "μ" (Greek letter "mu") in its name comes from the SI prefix "micro-", referring to the program's small memory footprint: the program was designed to use minimal computer resources while offering functionality comparable to larger BitTorrent clients such as Vuze or BitComet. μTorrent became controversial in 2015 when many users unknowingly accepted a default option during installation which also installed a cryptocurrency miner. The miner was removed in later versions, but had already done irreversible damage to μTorrent's reputation.[citation needed]

The program has been in active development since its first release in 2005. Although originally developed by Ludvig Strigeus, since December 7, 2006, the code is owned and maintained by BitTorrent, Inc. The code has also been employed by BitTorrent, Inc. as the basis for version 6.0 and above of the BitTorrent client, a re-branded version of μTorrent. All versions are written in C++.