HackerRank

While it is designed for those with previous coding experience, HackerRank is one of the biggest competitive programming websites available. HackerRank helps you code, create, and collaborate with an IDE built to showcase real-world skills in a real-world environment. With online challenges and leaderboards to see how you score, this coding community can show you how your programming stands up against the competition.

It's not all a contest, though; HackerRank offers you lots of lessons and explanations to help you improve your abilities — and because it's aimed at helping developers get noticed by major tech organizations, it may help you earn a job. The challenges appeal to people of all skill levels, the lessons help beginners, and the forums are an excellent resource for learning more. It is also an excellent platform for assessing technical expertise, with features such as live coding and the capacity to customize your application process to your organization's specific needs.

"The challenges are great for every skill level. They manage a diverse set of programming languages"; "I like the different paths it offers for different programming languages. And it also offers free certification on many skills like algorithms and data structures", the website users' feedback.

Website: hackerrank.com