HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.
Courseroot - Biggest online course database on the web
AlgoExpert.io - A better way to prep for tech interviews
Alcamy - Free, open self-learning platform. Learn & teach anything.
Codility - Codility provides a SaaS platform with advanced validation, security and protection features to evaluate the skills of software engineers.
Startup Stash - A curated directory of 400 resources & tools for startups