PythonTutor is a web-based tool that helps you understand code like a friend explaining it step-by-step! Since 2010, it’s helped over 20 million learners visualize how Python, Java, JavaScript, C, C++, and Ruby programs run. Write code in your browser, watch variables and memory change with each line, and debug with an AI tutor for instant help. Features include a visual debugger, function call tracking, iframe embedding for classrooms, and support for small code snippets. It is ideal for students learning programming, teachers explaining concepts, or beginners grasping algorithms, it’s free, open-source, and super easy to use.