Qt Licensing
Qt is available under different licensing options designed to accommodate the needs of our various users:
- Qt licensed under commercial licenses are appropriate for development of proprietary/commercial software where you do not want to share any source code with third parties or otherwise cannot comply with the terms of the GNU LGPL version 3.
- Qt licensed under the GNU Lesser General Public License (LGPL) version 3 is appropriate for the development of Qt applications provided you can comply with the terms and conditions of the GNU LGPL version 3 (or GNU GPL version 3).
Note: Some specific parts (modules) of the Qt framework are not available under the GNU LGPL version 3, but under the GNU General Public License (GPL) instead. See Licenses Used in Qt for details.
Qt documentation is licensed under the terms of the GNU Free Documentation License (FDL) version 1.3, as published by the Free Software Foundation. Alternatively, you may use the documentation in accordance with the terms contained in a written agreement between you and The Qt Company.
See http://qt.io/licensing/ for an overview of Qt licensing.
Purchasing and Sales Information
To purchase a Qt license, visit http://www.qt.io/download/.
For further information and assistance about Qt licensing, contact our sales; see http://www.qt.io/locations/ for contact details.
Licenses Used in Qt
The following table lists parts of Qt that incorporate code licensed under licenses other than GNU Lesser General Public License (LGPL) or the commercial license, as well as Qt modules that are only available under a specific license or a version of a license.
Third-party licenses used in libraries that are supplied alongside Qt modules are also listed.
Note: Cross-module dependencies are also described on a general level. All Qt modules depend on Qt Core.
| Qt Module/Tool | Component | Description | License Type | Notes |
|---|---|---|---|---|
| Qt Core | ||||
| QSegfaultHandler | Parts of implementation of QSegfaultHandler class. | BSD-style | ||
| QUrl | Implementation of QUrl::fromUserInput(). | Modified BSD | ||
| Cocoa Platform Plugin | Specific parts of the Qt for macOS Cocoa port. | BSD-style | Qt for macOS | |
| qtmain library | A helper library for writing a cross-platform main() function on Windows. | Modified BSD | Qt for Windows | |
| Shift-JIS Text Codec | A character encoding for Japanese. | BSD-style | ||
| ISO-2022-JP (JIS) Text Codec | A widely used encoding for Japanese. | BSD-style | ||
| EUC-JP Text Codec | EUC-JP is a variable-width encoding used to represent the elements of three Japanese character set standards. | BSD-style | ||
| EUC-KR TextCodec | Extended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese. | BSD-style | ||
| GBK Text Codec | GBK is an extension of the GB2312 character set for simplified Chinese characters, used mainland China. | BSD-style | ||
| Big5 Text Codec | Big5, or BIG-5, is a Chinese character encoding method used for Traditional Chinese characters. | BSD-style | ||
| Big5-HKSCS Text Codec | Big5-HKSCS is a Chinese character set with more than 4700 characters. | BSD-style | ||
| TSCII Text Codec | The TSCII codec provides conversion to and from the Tamil TSCII encoding. | BSD-style | ||
| Stack-less Just-In-Time compiler | A platform-independent JIT compiler. | BSD | ||
| Parts of the codecs implemented by Qt | BSD | |||
| Unicode | Unicode character data. | Permissive, GPL-compatible | ||
| Macros for building Qt files | Macros used in CMake files for building Qt. | BSD | ||
| The PCRE library | The PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5. | BSD-style | ||
| Third-party Licenses | ||||
| Android C++ Run-time | GNU C++ run-time library (libstdc++) for Android. | GPLv3 with exception | Qt for Android | |
| forkfd | A tool to facilitate spawning sub-processes. | MIT | Unix systems | |
| FreeBSD strtoll and strtoull | Functions for converting a string to long long integer. | BSD | ||
| V8 double/string conversion library | Functions for converting between strings and doubles. | BSD | ||
| MD4 | implements the MD4 message-digest algorithm. | BSD | ||
| MD5 | implements the MD5 message-digest algorithm. | BSD | ||
| Mesa llvmpipe | Mesa llvmpipe software rasterizer backend (opengl32sw.dll) for Windows builds. | MIT | Qt for Windows | |
| SHA-1 | implements the SHA-1 encryption algorithm. | BSD | ||
| SHA-3 | implements the SHA-3 encryption algorithm. | BSD | ||
| zlib | zlib is a general purpose data compression library. | BSD-style | ||
| The Public Suffix List | A list of all known public Internet suffixes. | Mozilla Public License | ||
| Qt Gui | ||||
| QKeyMapper | Internal class for key mapping. | Custom, BSD-style | Qt for Linux/X11 | |
| QImage | Code used for smooth scaling in QImage::transformed(). | BSD | ||
| Third-party Licenses | ||||
| FreeType | Parts of FreeType project used in font rendering. | GPLv2, FreeType Project License | ||
| HarfBuzz | OpenType layout engine. | BSD-style | ||
| FreeType 2 | Parts of FreeType project used in font rendering. | GPLv2, FreeType Project License | ||
| PNG Reference Library | A library for reducing the time and effort it takes to support the PNG format. | BSD-style | ||
| Pixman | Pixman is a library that provides low-level pixel manipulation features such as image compositing and trapezoid rasterization. | BSD-style | ||
| Drag and Drop | Allows users to transfer information between and within applications. | BSD-style | ||
| ANGLE | Opensource project to map OpenGL ES API calls to DirectX API. | BSD-style | Qt for Windows | |
| Qt Location | ||||
| Third-party Licenses | ||||
| Poly2Tri | Poly2Tri is a sweepline constrained Delaunay Polygon Triangulation Library. | BSD-style | ||
| Clipper | Clipper is a freeware library for clipping and offsetting lines and polygons. | BSD-style | ||
| Clip2Tri | Clip2Tri is an open source polygon triangulation library based on Poly2Tri. | MIT | ||
| Qt Bluetooth | ||||
| Third-party Licenses | ||||
| BlueZ | BlueZ is a Bluetooth stack for Linux based operating systems | GPL v2 | Used by sdpscanner tool which is called by Qt Bluetooth on BlueZ 5 systems. Qt applications do not link to GPL code. | |
| Qt Multimedia | ||||
| Third-party Licenses | ||||
| FFTReal | Fast Fourier transform of real-valued arrays. | LGPL | (Used in example code). | |
| Qt Canvas 3D | ||||
| Third-party Licenses | ||||
| three.js | JavaScript 3D library | MIT | (Used in example code) | |
| Three.js Loader | A parser for loading 3D models from JSON data structures. | MIT | (Used in example code). | |
| gl-matrix.js | High performance matrix and vector operations | MIT | (Used in example code). | |
| Qt SVG | ||||
| Qt SVG License Information | Parts of code for arc handling in Qt SVG module. | BSD-style | Depends on Qt Gui, Qt Widgets | |
| Qt QML | ||||
| Third-party Licenses | ||||
| JavaScriptCore Macro Assembler | The assembly code generated use by the JIT. | BSD-style | ||
| Qt Quick | ||||
| Third-party Licenses | ||||
| Easing Equations | Easing Equations is a collection of swappable functions that add flavor to motion. | BSD-style | Depends on Qt QML, Qt Gui, Qt Network | |
| Qt Quick Controls | ||||
| Native Style for Android | Apache License 2.0 | Qt for Android | ||
| Qt Script | (Provided for Qt 4 compatibility) | |||
| V8 benchmark tests | V8 benchmark tests used in Qt Script. | BSD-style | ||
| Sunspider benchmark tests | Sunspider benchmark tests used in Qt Script. | BSD-style | ||
| Third-party Licenses | ||||
| JavaScriptCore | LGPL v2 | |||
| Qt Test | ||||
| Testlib | Parts of implementation of Qt Test library. | BSD, MIT | ||
| Third-party Licenses | ||||
| Valgrind | A code analysis tool for detecting memory leaks. | GPL v2 | ||
| valgrind.h specific license | BSD-style | |||
| Callgrind | A performance profiling tool. | GPL v2 | ||
| Qt Print Support | Depends on Qt Gui and Qt Widgets | |||
| PDF Licensing | Notes about PDF Licensing. | |||
| Qt Wayland | ||||
| Wayland Protocol | MIT | |||
| Qt WebEngine | ||||
| Qt WebEngine Core | LGPL v3 or GPL v2 + Qt commercial license | |||
| Third-party Licenses | ||||
| Chromium | Third-party licenses in Chromium | LGPLv2.1, BSD, BSL, Apache, APSL, MIT, MPL, others | See Qt WebEngine Licensing for details. | |
| Qt Designer | ||||
| Qt Designer License Information | Implementation of the recursive shadow casting algorithm in Qt Designer. | BSD (MIT) | ||
| Qt Creator | ||||
| Third-party Licenses | ||||
| Botan | A C++ crypto library used in Qt Creator. | BSD | ||
| Qt Image Formats | ||||
| Third-party Licenses | ||||
| JasPer | A collection of software for the coding and manipulation of images. | BSD-style | ||
| TIFF | libtiff is a set of C functions (a library) that support the manipulation of TIFF image files. | BSD | ||
| MNG | Support decoding and displaying of MNG format image files. | BSD-style | ||
| WebP | Support decoding and displaying of WebP format image files. | BSD-style | ||
| Qt SQL | ||||
| SQLite | A C library that implements a self-contained, embeddable, zero-configuration SQL database engine. | BSD-style | ||
| Qt XML Patterns | ||||
| Bison Parser | Bison is a parser generator. | GPL with exception | Depends on Qt Network | |
| Qt 3D | ||||
| Third-party Licenses | ||||
| assimp | Open Asset Import Library | BSD | ||
| Plugins | ||||
| JPEG | C software to implement JPEG image compression and decompression. | BSD-style | ||
| IAccessible2 | An accessibility API for Microsoft Windows applications. | BSD | Qt for Windows | |
| Cycle | A CPU tick counter. | MIT | ||
| callgrind.h specific license | BSD-style | |||
| xcb | A C language binding for the X Window System. | BSD-style | Qt for Linux/X11 | |
| at-spi and at-spi2 | A toolkit-neutral way of providing accessibility facilities in application. | LGPL | Qt for Linux/X11 | |
| xkbcommon | Keymap handling library for toolkits and window systems. | BSD-style | Qt for Linux/X11 | |
| Qt Tools | ||||
| Third-party Licenses | ||||
| Clucene Core Library | A high-performance, full-featured text search engine written in C++. | LGPL/Apache | ||
The following modules are available under the GNU GPL version 3 and commercial licenses:
| Qt Module/Tool | Component | Description | License Type |
|---|---|---|---|
| Qt Charts | GPLv3 or commercial license | ||
| Qt Data Visualization | GPLv3 or commercial license | ||
| Qt Purchasing | GPLv3 or commercial license | ||
| Qt Virtual Keyboard | GPLv3 or commercial license | ||
| Third-party Licenses | |||
| Lipi Toolkit | An open source toolkit for online Handwriting Recognition (HWR). | MIT-Style License | |
| OpenWnn | A Japanese IME | Apache License | |
| Pinyin | An IME for Standard Chinese input. | Apache License | |
| tcime | A traditional Chinese IME. | Apache License | |
| Qt Quick 2D Renderer | GPLv3 or commercial license | ||
| Third-party Licenses | |||
| EGL 1.5 Headers | These headers are based on EGL 1.5 specification. | MIT License | |
| OpenGL ES 2.0 Headers | These headers are based on OpenGL ES 2.0 specification. | MIT and SGI License | |
| OpenGL ES 3.1 Headers | These headers are based on OpenGL ES 3.1 specification. | MIT and SGI License | |
| OpenKODE Core 1.0 Header | The header is based on OpenKODE Core 1.0 specification. | MIT License | |
| V8 double/string conversion library | String conversion routines for IEEE doubles. | BSD-style | |
Additional information
The documents below list related documents, such as information about Trademark and other licenses used in parts of Qt.
Details of restrictions on the use of PDF-related trademarks. | |
License information for third-party libraries supplied with Qt. | |
Provides additional information about the licensing of run-time dependencies of Qt for Android | |
Information about the licenses of fonts supplied with Qt | |
Information about open source licensing of Qt. | |
Information about trademarks owned by The Qt Company and other organizations. | |
Describes the use and license of the qtmain helper library. | |
License information for contributions by Apple, Inc. to specific parts of the Qt for macOS Cocoa port. | |
License information for Qt SVG |
© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.