Composer is the dependency manager for PHP and you are on a one-page-only documentation for this tool.
Official documentation is on the official website, this page just brings you the essential.

• Composer CheatSheet for developpers @ GitHub.

Fast detection of composer dependency issues (unused dependencies, shadow dependencies, misplaced dependencies)

Run Composer packages, effortlessly. The entire PHP ecosystem, always at your fingertips.

Run any command from any composer package, even if it's not installed in your project.

• cpx @ GitHub.

PHP Installer for Extensions

PHP Extension installer

Pickle is a new PHP extension installer. It is based on Composer and the plan is to get Composer to fully support it.

Composer repository for private PHP packages.
Private Packagist makes the code in your private repositories available for use with Composer.

This package provides a wonderful PHP skeleton to start building your next package idea.

PHPSandbox + Packagist.
This is a playground to try Composer packages. With it, you can try 350k+ packages using a standard PHP v8.1 environment.

This class is a port of the original Sphinx API class by Andrew Aksyonoff and Sphinx Technologies Inc to PHP 5.3 and above.