HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
CodeForces - Programming competitions and contests, programming community.
AlgoExpert.io - A better way to prep for tech interviews
Codility - Codility provides a SaaS platform with advanced validation, security and protection features to evaluate the skills of software engineers.
LeetCode - Practice and level up your development skills and prepare for technical interviews.
Codechef - CodeChef is a not-for-profit educational initiative by Directi, an Indian software company. It is a global programming community that fosters learning and friendly competition, built on top of the world’s largest competitive programming platform.