Wikipedia
HackerRank is a company that focuses on competitive programming challenges for both consumers and businesses and has an online community of over one million computer programmers. HackerRank's programming challenges can be solved in a variety of programming languages (including Java, C++, PHP, Python, SQL) and span multiple computer science domains.
On the consumer side, when a programmer submits a solution to a programming challenge, their submission is scored on the accuracy of their output and the execution time of their solution. Programmers are then ranked globally on the HackerRank leaderboard and earn badges based on their accomplishments to drive competition among users. In addition to individual programming challenges, HackerRank also hosts contests (often referred to by HackerRank as "CodeSprints") where users compete on the same programming challenges during a set period of time and are then ranked at the conclusion of the event. HackerRank is seen as a market leader in the growing gamification trend within competitive computer programming and the consumer-side of their website is free for coders to use.