Qt Project

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Qt Project
Founded21 October 2011; 11 years ago (2011-10-21)
FocusFree software
ProductsQt, Qt Creator
MethodDevelopment and documentation
WebsiteThe Qt Company

The Qt Project is an open collaboration effort to coordinate the development of the Qt software framework. Initially founded by Nokia in 2011,[1] the project is now led by The Qt Company.[2]


KDE mascot Konqi showing its Qt heart.

Haavard Nord and Eirik Chambe-Eng (the original developers of Qt and the CEO and President, respectively, of Trolltech) began development of "Qt" in 1991, three years before the company was incorporated as Quasar Technologies, then changed the name to Troll Tech and then to Trolltech.[3]

Until version 1.45 the source code of Qt was released under the Qt Free Edition License.[4] This was viewed as not compliant with the open source principle by the Open Source Initiative and the free software definition by Free Software Foundation because, while the source was available, it did not allow the redistribution of modified versions.

Controversy arose around 1998 when it became clear that KDE's K Desktop Environment was going to become one of the leading desktop environments for Linux. As it was based on Qt, many people in the free software movement worried that an essential piece of one of their major operating systems would be proprietary.

With the release of Qt 2.0, the license was changed to the Q Public License (QPL), a free software license but one regarded by the Free Software Foundation as incompatible with the GPL. A compromise was found between KDE and Trolltech whereby Qt would not be able to fall under a more restrictive license than the QPL, even if Trolltech was bought out or went bankrupt. This led to the creation of the KDE Free Qt Foundation which guarantees that Qt would fall under a BSD-style license should no free/open source version of Qt be released during a period of 12 months.[5]

In 2000, Qt 2.2 was released under the GPL v2, ending all controversy regarding GPL compatibility.[6]

On 28 January 2008 Nokia announced to acquire Trolltech.[7][8]

On 14 January 2009 Qt version 4.5 was relicensed, adding LGPL as licensing option.[9]

The Qt Project was founded on 21 October 2011.[1][10] In August 2012 Digia announced to acquire all rights to Qt and take Nokia's role within the Qt Project.[2]


The Qt Project is not a separate legal entity or organization; Digia retains all trademarks around Qt.[11][12]

Qt's Open Governance is modelled after WebKit's.[13][14]

Decision-making takes place in a process the project describes as "lazy consensus".[15]

The project facilitates online communication among its developers and community members through public forums,[16] mailing lists,[17] and wiki pages.[18]

Participating organizations[edit]

Distribution of non-Digia Qt contributors (2013, Week 18)

Aside from the project leader Digia and various individuals, a number of other organizations participate in the Qt Project.[19] Second-largest Qt contributor is KDAB, a Swedish Qt consulting company.[20] KDAB is involved in many areas, including maintenance of several components.[21][22] KDAB together with RIM/BlackBerry are maintaining the QNX and BlackBerry 10 ports of Qt.[19][23]

Another big participator is Intel, contributing for example Wayland support.[24] AudioCodes maintains IBM ClearCase support in Qt Creator.[25]

Many contributions also come from the KDE community, which is oftentimes adding features from their KDE Frameworks upstream into Qt.[26][27]

See also[edit]


  1. ^ a b Lydia Pintscher (21 October 2011). "KDE Applauds Qt's Move to Open Governance". KDE.News. Retrieved 8 May 2013.
  2. ^ a b "Digia to acquire Qt from Nokia". Digia.com. Archived from the original on 5 March 2013. Retrieved 19 March 2013.
  3. ^ "A Brief History of Qt". Archived from the original on 30 June 2008. Retrieved 20 December 2007.
  4. ^ "Qt Free Edition License". Trolltech. 1992. Archived from the original on 14 October 2016. Retrieved 14 October 2016.
  5. ^ "Free Qt Foundation". KDE. Retrieved 8 May 2013.
  6. ^ "Trolltech to Release Qt Under GPL - Decision Alters Linux GUI Landscape - Reports". LinuxPlanet. 4 September 2000. Retrieved 8 May 2013.
  7. ^ "Nokia to acquire Trolltech to accelerate software strategy". 28 January 2008. Retrieved 28 January 2008.
  8. ^ Paul, Ryan (28 January 2008). "Nokia to buy Trolltech, will become a patron of KDE". Ars Technica. Retrieved 8 May 2013.
  9. ^ "Qt Everywhere: 4.5 To Be Relicensed As LGPL". 14 January 2009. Retrieved 8 May 2013.
  10. ^ Meyer, David (24 October 2011). "Nokia gives Qt open-source governance". ZDNet. Retrieved 8 May 2013.
  11. ^ "About us - Digia Plc". Qt.digia.com. 13 September 2011. Archived from the original on 30 May 2013. Retrieved 8 May 2013.
  12. ^ "Qt Project". Qt Project. Retrieved 8 May 2013.
  13. ^ "Nokia: Qt 5 soll im April 2012 erscheinen" (in German). Golem.de. 16 June 2011. Retrieved 8 May 2013.
  14. ^ Anita Klingler (24 October 2011). "Nokia startet Qt-Projekt mit unabhängiger Infrastruktur" (in German). Zdnet.de. Retrieved 8 May 2013.
  15. ^ "The Qt Governance Model - Qt Wiki". wiki.qt.io. Retrieved 20 July 2022.
  16. ^ "forums". Qt Project. Retrieved 8 May 2013.
  17. ^ "Mailing Lists". Lists.qt-project.org. Retrieved 8 May 2013.
  18. ^ "index | Qt Wiki". Qt Project. 29 March 2013. Retrieved 8 May 2013.
  19. ^ a b Macieira, Thiago. "Qt Project Statistics". Thiago Macieira's blog. Macieira.org. Retrieved 8 May 2013.
  20. ^ "contributions to Qt 5.0 (part 1)". KDAB. 20 December 2012. Retrieved 8 May 2013.
  21. ^ "contributions to Qt 5.0 (part 2)". KDAB. 21 December 2012. Retrieved 8 May 2013.
  22. ^ "Maintaining Qt3D". KDAB. 21 December 2012. Retrieved 8 May 2013.
  23. ^ "Qt5 on the QNX operating system". KDAB. 19 April 2012. Retrieved 8 May 2013.
  24. ^ "[Phoronix] Qt Is Now Drawing On Wayland". Phoronix.com. 21 September 2010. Retrieved 8 May 2013.
  25. ^ "Maintainers | Qt Wiki". Qt Project. 12 April 2013. Retrieved 8 May 2013.
  26. ^ "Frameworks/Epics/Contributions to Qt5". KDE Community Wiki. Retrieved 27 April 2015.
  27. ^ "Project Qt/Latest/Mod". KDE Community Wiki. Retrieved 10 March 2022.

External links[edit]