LeetCode provides a wide range of coding problems, from easy to hard, with daily challenges and regular contests to test your skills. Compete with others and improve your problem-solving abilities.

HackerRank offers coding challenges across various domains, including algorithms, data structures, and mathematics. Engage in daily challenges and participate in hackathons to sharpen your coding skills.

Codewars provides a gamified experience for coding challenges, where you can solve "kata" problems and advance through the ranks. It’s a fun and interactive way to practice coding daily.

The Educative offers interactive courses with embedded coding challenges designed to test your knowledge as you learn. Their platform is ideal for developers who want to practice coding in an integrated learning environment.