BitLord is a free, ad-supported and proprietary BitTorrent client for Microsoft Windows and macOS, promoted as "The easiest torrent downloader". The program uses the libtorrent-rasterbar C++ library. BitLord is as of version 2.4 built using Python and the Qt cross-platform framework. It is capable of streaming video, using a built in version of VLC.
BitLord was first released in December 2004, as BitLord 0.56, based on and under license from BitComet. From version 1.2 until 2.3.2 BitLord, was based on Deluge, but has added several features of its own since then.
Features specific to BitLord are:
A built-in video player (VLC).
Ability to stream video and audio files.
Subtitles using API from opensubtitles.org
A built-in torrent search engine with safety verification to avoid malicious files.
Comment system to write and read comments on torrents you are downloading.
A torrent RSS reader.
A "Tracker Adder" that adds trackers that BitLord knows about to your torrent.
Main features supported through use of LibTorrent:
Peer exchange (PEX) with other BitTorrent clients:
libtorrent and clients based on it like Deluge have full µTorrent PEX support
Transmission and clients based on libTransmission have full µTorrent PEX support
KTorrent has full µTorrent PEX support as of 2.1 RC1
Vuze, formerly Azureus, has full support as of version 3.0.4.3
Supports trackerless torrents (using the Mainline kademlia DHT protocol). BEP 5
Supports the bittorrent extension protocol, BEP 10.
Supports the µTorrent metadata transfer protocol (i.e. magnet links) BEP 9
supports local peer discovery (multicasts for peers on the same local network)
Multitracker extension support (supports both strict BEP 12 and the µTorrent interpretation).
Tracker scrapes
Supports lt_trackers extension, to exchange trackers between peers
HTTP seeding, as specified in BEP 17 and BEP 19.
Supports the udp-tracker protocol. (BEP 15).
Supports the no_peer_id=1 extension that will ease the load off trackers.
Supports the compact=1 tracker parameter.
Super seeding/initial seeding (BEP16).
Private torrents (BEP 27).
Support for IPv6, including BEP 7 and BEP 24.
Support for merkle hash tree torrents. This makes the size of torrent files scale well with the size of the content.
Uses a separate disk I/O thread to not have the disk ever block on network or client interaction.
Supports files larger than 2 gigabytes on systems that support it.
Fast resume support, a way to get rid of the costly piece check at the start of a resumed torrent. Saves the storage state, piece_picker state as well as all local peers in a separate fast-resume file.
Has an adjustable read and write disk cache for improved disk throughput.
Queues torrents for file check, instead of checking all of them in parallel.
Does not have any requirements on the piece order in a torrent that it resumes. This means it can resume a torrent downloaded by any client.
Supports both sparse files and compact file allocation (where pieces are kept consolidated on disk)
Seed mode, where the files on disk are assumed to be complete, and each piece's hash is verified the first time it is requested.
Adjusts the length of the request queue depending on download rate.
Serves multiple torrents on a single port and in a single thread
Supports http proxies and basic proxy authentication
Supports gzipped tracker-responses
Can limit the upload and download bandwidth usage and the maximum number of unchoked peers
Possibility to limit the number of connections.
Delays have messages if there's no other outgoing traffic to the peer, and doesn't send have messages to peers that already has the piece. This saves bandwidth.
Selective downloading. The ability to select which parts of a torrent you want to download.
IP filter to disallow ip addresses and ip ranges from connecting and being connected
NAT-PMP and UPnP support (automatic port mapping on routers that support it)
Old releases of BitLord (up to version 1.1) are based on the source code of version 0.56 of the BitComet core. Because of this, certain bugs that have been resolved in later versions of BitComet were still prevalent in BitLord. BitLord has also been criticized for what some perceive as "selfish behavior" and is blocked by some BitTorrent Trackers. In 2007, BitLord 2.0 Beta supposedly resolved these issues and added eDonkey support. The beta version is no longer available from the BitLord website, though installers hosted on other servers still work.
The only major changes in releases of BitLord prior to version 1.2 were the addition of advertisements into the BitLord interface and the replacement of BitComet's list of BitTorrent sites with a search box.
The developers have claimed for a long time that BitLord is open source, but has recently officially made it closed source / proprietary software.
