HackerRank is an online platform that provides a wide range of programming challenges and coding competitions, as well as a learning environment for developers and coding enthusiasts. It serves as a virtual hub where programmers can improve their coding skills, practice algorithms, and compete with others in a variety of programming domains.

The platform offers a vast collection of coding challenges across different programming languages and domains such as algorithms, data structures, artificial intelligence, databases, and more. These challenges are designed to test problem-solving abilities and coding proficiency.