LeetCode is an online platform designed for software engineers and developers to practice coding skills through a variety of programming challenges. It offers a wide range of problems categorized by difficulty levels, allowing users to improve their problem-solving abilities and prepare for technical interviews. In addition to coding challenges, LeetCode provides resources such as discussion forums, tutorials, and mock interviews. Users can also track their progress and compete with others in coding contests, making it a popular choice for those looking to enhance their programming knowledge and skills.