CodeSignal - CodeSignal is the leading assessment platform for technical hiring.
codebunk - Realtime Collaborative Editor with Code Execution, REPLs and Chat
Codility - Codility provides a SaaS platform with advanced validation, security and protection features to evaluate the skills of software engineers.
Floobits - Floobits brings real-time collaborative editing to text editors, IDEs, and now Atom.
HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
coderpad - Collaborative code editor with in-browser, real-time execution. Conduct programming phone screens like a boss.