PHPStan

PHPStan is a static analysis tool for PHP that finds bugs in code without running it or writing tests. It scans the whole codebase for obvious and tricky bugs, including in rarely executed branches not covered by tests.

PHPStan runs on a developer machine and in continuous integration, and is designed to be legacy-friendly, working even on old code without an autoloader. It can be tried online.

PHPStan is open source and free, distributed under the MIT licence and actively developed on GitHub (version 2.3.1 in October 2026). PHPStan Pro is a paid package that adds a web interface to browse errors and continuous analysis in the background.