HackerRank
Solve coding problems by topic and take skill tests
HackerRank lets you solve coding problems in the browser and have them checked right away. Practice areas include algorithms, data structures, math, SQL, databases, Linux shell, React and languages such as C, C++, Java, Python and Ruby. There are also contests, skill tests that give a certificate and AI mock interviews.
Free · Browser · Beginner
About HackerRank
It trains basic to advanced problem solving and is a common way to get ready for the coding tests many companies use. It suits students and job seekers who want a broad place to practice.
You can create a free account. Much of the site is aimed at companies that hire, but the practice, contest and certification sections are open to individual developers.
On Breakpoint since 23 Oct 2026.