schemadiff` is an open-source command-line tool to generate diffs between two MySQL databases, built as a thin wrapper around Vitess's `schemadiff` library. It can be used to validate, normalize, and diff schemas loaded from various sources, including the standard input, file system, or MySQL database. The tool supports MySQL 8 syntax and is released under Apache 2.0 license. With `schemadiff`, users can easily compare two schemas and generate the necessary DDL to execute to get them in sync, making it useful for workflow enabling zero downtime schema migrations like PlanetScale's database branching.