Real Dev - Real-life coding skill challenge
hackattic - No nonsense, real world programming challenges
HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
Takehome - Effective and humane coding challenges for candidates
Career Switch To Coding - Converting newly minted coding skills into a dream career
Lytmus - Lytmus automates technical recruiting.