Qt 5.7 | Qt Licensing

Qt 5.7.1 Reference Documentation

# 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.

Notes about PDF Licensing | Details of restrictions on the use of PDF-related trademarks
Third-Party Licenses Used in Qt | License information for third-party libraries supplied with Qt.
Android GNU C++ Run-time Licensing | Provides additional information about the licensing of run-time dependencies of Qt for Android
Licenses for Fonts Used in Qt for Embedded Linux | Information about the licenses of fonts supplied with Qt
Open Source Licensing of Qt | Information about open source licensing of Qt.
Trademarks | Information about trademarks owned by The Qt Company and other organizations.
The qtmain Library | Describes the use and license of the qtmain helper library.
Contributions to the Cocoa Platform Plugin Files | License information for contributions by Apple, Inc. to specific parts of the Qt for macOS Cocoa port.
Qt SVG License Information | License information for Qt SVG