|Initial release||1999/2000 [?] (first version)|
|Operating system||Microsoft Windows, and Mac OS and Linux in the newest QT client|
Soulseek is a peer-to-peer (P2P) file-sharing network and application. The term Soulseek might refer to (1) one of the two networks, or (2) one of the three official user client interfaces. Soulseek is used mostly to exchange music, although users are able to share a variety of files. Soulseek was created by Nir Arbel, a former Napster programmer.
Two independent networks make up Soulseek since 2006, both run by the same management. The older and now the less used one is accessed by SoulSeek client 156; the newer network and one with greatest usage is accessed by SoulSeek client 157 (Windows only) or SoulSeekQT (Microsoft Windows, Mac OS, or Linux platforms). There are reportedly five times more users on the network accessed by clients 157/QT than 156 as of August 2011.
New developments are solely on the SoulSeekQT client interface. Work on Client 157 (Windows only) stopped in 2008. SoulSeekQT has somewhat different functionality compared to the 157 client interface.
Key features 
As a peer to peer (P2P) file sharing program, the accessible content is determined by the users of the Soulseek client, and what files they choose to share. The network has historically had a diverse mix of music, including underground and independent artists, unreleased music, such as demos and mixtapes, bootlegs, live tracks, and live DJ sets, but copyrighted releases from major and independent labels can also be found.
Central server 
Soulseek depends on a pair of central servers. One server supports the original client and network Version 156, with the other supporting the newer network (functioning with clients 157 and QT). While these central servers are key to coordinating searches and hosting chat rooms, they do not actually play a part in the transfer of files between users, which takes place directly between the users concerned. (See Single Source Downloads below).
Users can search for items; the results returned being a list of files whose names match the search term used. Searches may be explicit or may use wildcards/patterns or terms to be excluded. For example, searching for blue suede -shoes will return a list of files whose names containing the strings blue and suede, but files containing the string shoes in their names will be excluded.
A feature specific to the Soulseek search engine is the inclusion of the folder names and file paths in the search list. This allows users to search by folder name. For example, typing in experimental will return all the files that are contained in folders having that name, providing quick access to bands and albums in a determined musical genre.
The list of search results shows details, such as the full name and path of the file, its size, the user who is hosting the file, together with that users' average transfer rate, and in the case of mp3 files, brief details about the encoded track itself, such as bit rate, length, etc. The resulting search list may then be sorted in a variety of ways and individual files (or folders) chosen for download.
The Soulseek protocol search algorithms are not published, as those algorithms run on the server.
Single source (one-to-one) downloads 
Soulseek does not support multi-source downloading or "swarming" like other post-Napster clients, and must fetch a requested file from a single source. (By contrast, swarming allows a requested file to be sourced from a number of users who have that file, thus pieces of the file may be downloaded concurrently from a number of sources, typically giving improved performance.)
The 156 and 157 clients (but not QT, as of July 2011) also contain a ban feature whereby selected users may be banned from requesting files. This is in response to users who might be free-riding (i.e. taking files from others without sharing any files themselves) or who might be causing a nuisance for other reasons, such as a personal argument through the chat facilities or just taking up a user's bandwidth by downloading too many files, or simply on the whim of the banning user. Banning can be a contentious subject, and was the subject of much discussion in the user forums particularly in the early days. Users with download privileges can still be banned.
Album downloads 
While Soulseek, like other P2P clients, allows a user to download individual files from another by selecting each one from a list of search results, a Download Containing Folder option simplifies the downloading of entire albums. For example, a user who wishes to facilitate the distribution of an entire album may place all tracks relating to the album together in a folder on the host PC, and the entire contents of that folder (i.e. all the album's track files) can then be downloaded automatically one after the other using this one command.
File transfer monitoring 
The Soulseek client features two file transfer monitoring windows where the progress of files being uploaded and downloaded can be monitored and controlled.
User profiles 
Users may complete a profile which contains basic free-form text information (e.g. basic information about themselves or their 'file transfer rules') together with a list of things they like, a list of things they dislike, and optionally an image file. These items may then be viewed by other users when selecting the username from a list of members in a chat room or a list of files returned by a search.
The list of items a user likes may also be used to obtain global rankings for that item in the Soulseek community or to obtain recommendations from other users who have the same items in their list of things they like.
The Soulseek 156, 157 and QT clients provide a "wishlist" feature which functions like a stored search. Search terms are input as entries in a wishlist and each wishlist entry is then periodically executed as a search automatically by the client software, returning results as appropriate.
While the Soulseek software is free, a donation scheme exists to support the programming effort and cost of maintaining the servers. In return for donations, users are granted the privilege of being able to jump ahead of non-donating users in a queue when downloading files (but only if the files are not shared over a local area network).
Support forums and blog 
Like numerous other software titles, Soulseek has a set of forums where users may seek help on a variety of topics, such as technical aspects of using the software. Separate forums now support clients 156 and 157, and QT. The first blog was created in the latter part of 2003.
Soulseek is entirely financed by donations, with no advertising or user fees. Nir Arbel writes, as of July 1, 2008:
I would also like to take this opportunity to address some of the lies that have been spread about our lifestyle and the money we make off Soulseek. We live from hand to mouth. A few months ago we had to let go of sierracat, our system admin, despite his excellent work, because we could no longer afford his services. We are pretty heavily in debt. We are fighting a legal battle in France. We are not poor nor starving, but neither of us drives a fancy car nor could we begin to afford one if we wanted to. I don't like discussing money issues, but I feel it necessary to defend ourselves from accusations that are, and have always been, patently untrue. With that, I would like to thank you all for using Soulseek and making it a significant, if not hugely popular or successful, experience. Thanks.
Copyright issues 
Soulseek claims to be against copyright violation and that the purpose of their service is to promote unsigned artists. This is a quote from their homepage:
Soulseek® does not endorse nor condone the sharing of copyrighted materials. You should only share and download files which you are legally allowed to, or have otherwise received permission to, share.—quote
However, the above policy is apparently hardly enforced. Soulseek was taken to court in 2008 by two French music industry groups.
The original Soulseek user base around 2000 was composed mostly of members of the IDM mailing list, and most of the music first found on Soulseek was underground electronic music or music created by the users themselves. The developer released new versions of the client very frequently, according to new features or bugs fixes requested and noted by the users that helped greatly the developer Nir Arbel.
There is no known published data as to historical or present usage. Soulseek got a boost in 2002 when the site Audiogalaxy was closed down in 2002. Nir Arbel stated in an interview published December 26, 2003 that there were, at that time, over a million registered usernames and that 80,000–100,000 users log on during peak hours. When comparing the number of users in the then new feature of being able to create rooms in Soulseek, the most joined rooms before the shutdown of Audiogalaxy was around 50 or so people and then jumped to 100 or more after the shut down of Audiogalaxy. Soulseek is more a community than a simple file sharing client. In Soulseek users can find other users with similar music tastes, share information and files, chat and being part of chat rooms that they can create themselves inviting other users with similar tastes do discuss about their favorite music. Many musicians from the electronic scene are themselves too Soulseek users. Around 2004 Soulseek users from all the world met in Augsburg - Germany. Since then every year that meeting still takes place in a digital arts festival called Lab30 (30 being the street number of the Abraxas Theater)in Augsburg, Germany organized by longtime Soulseek user Manfred Genther and other Augsburg locals. This festival focuses on showcasing digital musicians, digital artists, and netlabels from all over the world. Many Soulseek artists have performed at the festival, and a large number of them have performed live for the very first time there. Lab30 has steadily grown in size since the first event, and continues to be a meeting place for the musicians and users of Soulseek. Attendees usually come from all over Europe and the United States. Lab30 is a well known event in Augsburg, and widely supported and cherished by the Augsburg music and art scene.
Soulseek Records 
Many of the original Soulseek users are also music producers, and Soulseek Records (not to be confused with "SLSK Records") was formed in 2002.
The first release was 139, which ran for about 12 months from 2002–03. Following a change in servers, a new version was released to coincide with this event. Whilst the main interface has largely remained unchanged since its inception, additional features such as the chat room 'ticker' were introduced into the 156 version.
Version 156 first appeared in 2005. A second 'test' version of the server, version 157, was set up shortly afterwards, which became the primary client in 2008.
Since July 6, 2008, there have been two versions of the Soulseek client, with entirely different users, user groups, and files. The older version, v.156 is progressively being wound down, but still operates as of August 2011, albeit with few users. Users are not obligated to upgrade, and new users may still inadvertently download the 156 client.
The 157 "test" network has been around since 2005, to circumvent poor search capability on the 156 client. The v.157 test 12c was released in November 2007. All recent versions have several bugs which can hang or cause the system to stop searching or downloading.
The client SoulSeekQT was set up in 2009.
For the older clients (156 and 157) no official client was developed for non-Windows operating systems, but a number of unofficial third-party clients existed at the time. Development of third-party clients was discouraged (but not prohibited), as coding errors or explicit circumvention of network rules in third-party clients had, at times, a drastic negative impact on the Soulseek network.
Non-Windows clients 
Another such client, named Nicotine, ran on all Unix-based systems, such as Mac OS X, and on Microsoft Windows. It may still be available from some package distributors on Linux-based systems. Nicotine-Plus (also styled as Nicotine+) is a continuation of the older Nicotine client and is based on the original PySoulSeek project. Nicotine+ runs under Linux and Windows.
GoSeek is a Soulseek client for Android devices.
MewSeek was originally iSlsk, a Soulseek client for iPod Touch and iPhone clients running jailbroken versions of iOS. MewSeek no longer supports Soulseek.
- . While other non Soulseek clients may still be able to access the network
- Thomas Mennecke: Interview with Nir Arbel Slyck.com December 26, 2003
- SoulSeekQT and 157 access one network, and 156 another. Effectively, the clients access separate networks, with separate userbases that do not communicate with each other. However both networks can be run simultaneously on the same (Windows) computer. The newer SoulseekQT (multi-OS) interface operates on the 157 network (albeit with somewhat different functionality compared to the old Windows 157 client).
- "Soulseek". Slsknet.org 157 forum. Retrieved 2011-08-11.
- "Soulseek". Slsknet.org 157 forum. Retrieved 2011-08-11.
- Dorian Moore
-  for more on the Soulseek Protocol
- Official website slsknet.org
- "New Beta-Client available – Soulseek Network Community Forums". Forums.slsknet.org. Retrieved 2010-04-01.
- Official website
- "Music Industry takes Soulseek to court", Torrentfreak
- IDM Mailing List – Hosted by Hyperreal.org
- "News SoulSeek Interview". Slyck.com. Retrieved 2010-04-01.
- Official website See SLSK
- "Other systems" (in (Russian)). Sensi.org. 2003-02-16. Retrieved 2010-04-01.
- MacUpdate.com. "Nicotine 1.0.8rev3". MacUpdate. Retrieved 2010-04-01.
- "Other systems". Other systems
- "Nicotine-Plus page at Sourceforge". Retrieved 2012-03-19.
- "Other systems and ssX". Solarseek.net. Retrieved 2010-04-01.