Psalm Requires PHP >= 7.1 and Composer.

composer require --dev vimeo/psalm

Add a psalm.xml config:

./vendor/bin/psalm --init [source_directory=src] [config_level=3]

where config_level represents how strict you want Psalm to be. 1 is the strictest, 8 is the most lenient.


$ ./vendor/bin/psalm --init src 3
Config file created successfully. Please re-run psalm.

Then run Psalm:


Psalm will probably find a number of issues - find out how to deal with them in Dealing with code issues.

Using the Phar

Sometimes your project can conflict with one or more of Psalm’s dependencies.

In that case you may find the Phar (a self-contained PHP executable) useful.

Run composer require --dev psalm/phar to install it.