Prettier is an open-source code formatter that helps developers maintain consistent code style across their projects. It automatically formats code in various programming languages, including JavaScript, HTML, and CSS, making it easier to read and understand. By enforcing a standard style, it reduces the time spent on code reviews and minimizes the chances of errors. Developed by James Long, Prettier integrates seamlessly with popular code editors like Visual Studio Code and Atom. It can be configured to fit specific project needs, allowing teams to customize formatting rules while still benefiting from its automatic formatting capabilities.