Just-in-time Code Formatting is the process of changing the formatting of any code to the way you want it. Imagine I send you a small project, you open it and find I have prefixed all fields with an underscore. Your development tool, understanding this as a problem, changes the variable prefix for you when you open it. It lays out the code the way you like it. and likewise, when I open it, its changes the way I like it.