This article is about the client. For the protocol, see BitTorrent. For bittorrent clients in general, see BitTorrent client
The BitTorrent client is a computer program developed by BitTorrent, Inc. used to download and upload files via the BitTorrent protocol.
The first client for the BitTorrent protocol was developed by Bram Cohen. He has also named his company, his software, and his protocol BitTorrent. The client software is often nicknamed "Mainline" by developers denoting its official origins. Version 4.20 of the client was dubbed "Allegro" by BitTorrent Inc., in reference to protocol extensions developed by the company to accelerate download performance and ISP manageability, according to "BitTorrent 4.20 Released" (Slyck News). Many alternative BitTorrent clients have been created since the initial release of BitTorrent, and some experts believe that the protocol will eventually be integrated into the download managers of web browsers, as evidenced by the integration by the Opera browser.
The BitTorrent client enables a user to search for and download torrent files, the main window including a Search box, (aka Search for torrents), that allows a search term to be entered and which then opens the user's default web browser at the BitTorrent torrents search engine page with the results of the search.
The current client enables a range of features including multiple parallel downloads. It also intermediates peering between itself, source file servers ("trackers") and other clients, thereby yielding great distribution efficiencies. The client also enables users to create and share torrent files.
BitTorrent Inc recently acquired µTorrent. µTorrent will remain closed source. Ludvig Strigeus, the writer of µTorrent will serve as a technical consultant, but BitTorrent Inc will do the majority of the development work.