Upath is a Node.js utility that provides a drop-in replacement for the built-in `path` module, ensuring consistent path handling across operating systems by converting all backslashes to forward slashes. It also adds functions for manipulating file extensions, such as adding, removing, changing, or setting default extensions, and includes utilities for safe path normalization and joining. This library is ideal for developers who need cross-platform path compatibility and advanced file extension management in their Node.js applications.