hackattic - No nonsense, real world programming challenges
Daily Coding Problem - Get exceptionally good at coding interviews
HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
FaceCode - Hire top tech talent with video interviews
Takehome - Effective and humane coding challenges for candidates
HackerEarth - HackerEarth is the network of top developers across the world. They connect to start-ups, tech companies, organizations and discover the best developer jobs. They participate in programming challenges and compete against other top developers.