An online Python compiler is a web-based tool that allows users to write, execute, and test Python code directly in their browser without the need for local installations. These platforms typically support Python 3.x versions and offer features like syntax highlighting, real-time code execution, and interactive debugging tools. They are ideal for learning, prototyping, and sharing code snippets, especially for beginners or those working on devices with limited resources. Some platforms also support popular libraries such as NumPy, Pandas, and Matplotlib, making them suitable for data analysis and scientific computing tasks.