Psi (instant messaging client)

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Psi icon new.png
Developer(s)The Psi Team
Initial releaseJuly 7, 2001[1]
Stable release1.4 (November 2, 2018; 11 months ago (2018-11-02)) [±]
Repository Edit this at Wikidata
Written inC++, Qt
Operating systemUnix-like, macOS, Microsoft Windows, Haiku
Available inChinese, Czech, English, French, German, Macedonian, Polish, Portuguese, Russian, Spanish, Ukrainian, Vietnamese
TypeInstant messaging client

Psi is a free instant messaging client for the XMPP protocol (including such services as Google Talk[3]) which uses the Qt toolkit. It runs on Linux (and other Unix-like operating systems), Windows, macOS and eComStation[4] (OS/2).[5]

Ready-to-install deb and RPM packages are available for many Linux distributions. Successful ports of Psi were reported for Haiku,[6] FreeBSD and Sun Solaris operating systems.

Due to Psi's free/open-source nature, several forks have appeared, which occasionally contain features that may appear in future official Psi versions. These official and unofficial builds are documented on their external wiki page.[7]

Project name[edit]

'Psi' is the twenty-third letter of the Greek alphabet (Ψ), which is used as the software's logo.

Mission statement[edit]

The goal of the Psi project is to create a powerful, yet easy-to-use XMPP client that tries to strictly adhere to the XMPP drafts and XMPP XEPs. This means that in most cases, Psi will not implement a feature unless there is an accepted standard for it in the XMPP community. Doing so ensures that Psi will be compatible, stable, and predictable.


The application was created by Justin Karneges and it began as a side project. At various points during its existence Karneges was paid to develop the codebase, during which Psi flourished. Typically however, the release cycle of Psi is relatively slow, but the client has always been seen by its fans as a very stable and powerful instant messaging client. Karneges left the project in late 2004 to pursue other endeavors.[8] In 2002 Michail Pishchagin started hacking Qt code which later became libpsi library. Pishchagin joined the team in March 2003 and he is responsible for many large chunks in Psi code.

In November 2004, maintenance was taken over by Kevin Smith, a long-time contributor to the project. In 2009, Smith handed maintenance back to Karneges[9], who also maintains Iris, the Qt/C++ XMPP library upon which Psi is based.[10]

Remko Tronçon started writing his custom patches for Psi in 2003, and became an official developer in May 2005.

In 2009 a Psi fork named Psi+ was started. Project purposes are: implementation of new features, writing of patches and plugins for transferring them to upstream. As of 2017 all active Psi+ developers have become official Psi developers[11], but Psi+ still has a number of unique features. From developers point of view Psi+ is just a development branch of Psi IM client which is hosted at separate git repositories and for which rolling release development model is used.


Because XMPP allows gateways to other services, which many servers support, it can also connect to Yahoo!, AIM, Gadu-Gadu, ICQ and Microsoft networks.[12] Other services available using gateway servers include RSS and Atom news feeds, sending SMS messages to cellular networks and weather reports.

As of 2012, Psi has language packs for 20 languages, with more being created.[13]

Emoticon packs are supported using the jisp format. Many jisp emoticon packs are available, including ones from AIM, iChat, and Trillian.

Psi supports file transfers between other XMPP clients, and it is possible to send to or receive files from other IM networks, if the user's servers support this. Psi supports Contact Is Typing Notification (which works with Yahoo!, MSN, and AIM contacts). Version 0.10, released in January 2006, brought automatically resizing contact list and composing window in chat dialogs, tabbed chats, support for Growl messaging system on Mac OS X, window transparency and many other changes.


Psi has official plugins with GnuPG[14], OTR[15] and OMEMO[16] encryption of private messages. Encryption of messages in group chats is supported only via OMEMO plugin.

See also[edit]


  1. ^ Karneges, Justin. "Justin's Homepage!". Psi. Archived from the original on December 18, 2001.
  2. ^ COPYING
  3. ^ "Other IM Clients". Google Talk Help. 2011. Retrieved January 24, 2012.
  4. ^ Psi build for OS/2. Version 0.15, ZIP package.
  5. ^ "XMPP Software: Clients". XMPP Standards Foundation. Retrieved January 24, 2012.
  6. ^ "Psi". BeBits. February 8, 2010. Retrieved January 24, 2012.
  7. ^ "Builds". Psi wiki. February 12, 2011. Retrieved January 24, 2012.
  8. ^ Karneges, Justin (November 25, 2004). "[Psi-devel] Passing the torch". psi-devel (Mailing list). Retrieved January 24, 2012.
  9. ^ Smith, Kevin (March 5, 2009). "[Psi-devel] Psi - under new^h^h^hold management". psi-devel (Mailing list). Retrieved January 24, 2012.
  10. ^ "Iris XMPP Library". Delta XMPP Project. Affinix Software. December 5, 2004. Retrieved January 24, 2012.
  11. ^ "". March 7, 2018. Retrieved March 7, 2018.
  12. ^ Popa, Roxana (May 29, 2007). "Psi Review". Softpedia. Retrieved January 24, 2012.
  13. ^ Popa, Bogdan (March 27, 2008). "Best 5 Jabber Clients for Windows in Pictures". Softpedia. Retrieved January 24, 2012.
  14. ^ GnuPG Plugin
  15. ^ OTR Plugin
  16. ^ OMEMO Plugin

External links[edit]