EditorConfig Deep Dive: Syntax, Properties, and Best Practices

Every shared repository eventually rediscovers the same avoidable argument: tabs or spaces, LF or CRLF, trim trailing whitespace or leave it alone, final newline or not. None of these questions are hard. They are just repetitive, noisy, and surprisingly good at wasting review time.
EditorConfig exists to move those decisions out of personal editor settings and into the repository itself. It is a simple, cross-editor standard for defining basic text file formatting rules so contributors using different editors and IDEs still save files in a consistent way.
This matters more than style bikeshedding. Inconsistent indentation creates ugly diffs. Inconsistent line endings break shell scripts and CI jobs. Trailing whitespace produces review noise that hides the change you actually care about. EditorConfig is not glamorous, but it solves a class of problems that should stay boring.
This guide covers how EditorConfig works, the syntax of .editorconfig files, the standard properties you can rely on, where editor support stands, and how to build a practical starter template for a modern repository.