Software for C++
CppCMS
CppCMS is a free and open-source, high performance web development framework. CppCMS is not a content management system but rather a C++ web framework that has been designed for rapid web application development. Applications built with CppCMS are capable high loads with high request throughput.
ReactOS
ReactOS is a free and open-source Windows-like operating system for amd64/i686 computers. ReactOS was designed to be binary-compatible with computer programs and device drivers made for Windows Server 2003 and Microsoft Windows NT family of operating systems including Windows NT4, Windows 2000, Windows XP, Windows 2003, Windows Vista and Windows Seven. To Some, ReactOS is a potential open-source drop-in replacement for Windows and for its information on undocumented Windows APIs
GDevelop
GDevelop is a 2D cross-platform, free and open-source game engine that takes visual programming to the next level. GDevelop allows you to take read-made behaviours and add them to your game objects or create new once with intuitive and east to use events. With GDevelop, it is easy to make games for PC and Mobile, as well as launch HTML5 games playable right in your web browser.
SerenityOS
SerenityOS is a graphical Unix-like operating system for desktop computers. The operating system is built from scratch in C++, by the Swede Andreas Kling and a community of developers of all levels. SerenityOS is a love letter to '90s user interfaces with a custom Unix-like core that is built form the ground-up to appeal to today's power-users that want to get things done. The build is monolithic in nature, while allowing anyone to contribute to the core, UI and software for the system.
RethinkDB
RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.
Sandboxie
Sandboxie is a free open-source sandboxing program for Windows. Sandboxie allows you to create isolated operating environment in which applications can be run and installed without permanently modifying the local system. This virtual environment allows for controlled testing of untrusted programs and web surfing.
Phototonic
Phototonic is a fast and functional, open source image viewer and organizer. The software is written in C++/Qt and released for free under GNU General Public License v3. Phototonic takes inpiration from traditional image views and provides overview of your inventory with thumbnails and organized layouts.
Vizzu
Vizzu is a free, open-source Javascript/C++ library utilizing a generic dataviz engine that generates many types of charts and seamlessly animates between them. It can be used to create static charts but more importantly it is designed for building animated data stories and interactive explorers as Vizzu enables showing different perspectives of the data that the viewers can easily follow due to the animation.
Cucumber
Cucumber is a BDD testing and collaboration platform. Whether you are building open source or proprietary software, Cucumber's collaboration tools will boost your engineering team's performance by employing Behavior-Driven Development (BDD).