wxWidgets - wxWidgets: Cross-Platform GUI Library
HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
Electron - Build cross platform desktop apps with web technologies
iMocha - Make intelligent talent decisions.
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.
Codility - Codility provides a SaaS platform with advanced validation, security and protection features to evaluate the skills of software engineers.