Edabit

Edabit serves up 10,000+ interactive coding problems ordered from beginner to expert difficulty. Each challenge includes immediate feedback, hints, and community solutions to learn from. The interface is clean and focused, and the challenges are genuinely bite-sized, so you can solve one in five minutes or spend an hour on harder problems without the platform imposing a lesson structure.

It's particularly strong for daily practice and skill reinforcement across multiple languages. The format suits developers who code in short sessions or want targeted practice in specific areas without committing to a full course, and the sheer volume of problems means you'll find plenty at your level.