Composer is a tool for dependency management in PHP. It is not a package manager in the same sense as Yum or Apt are. Yes, it deals with “packages” or libraries, but it manages them on a per-project basis, installing them in a directory (e.g. vendor) inside your project. By default it does not install anything globally.

PHP Standards Recommendations, PSR


The composer.json Schema

  • Introduction
  • Basic usage
  • Libraries
  • Command-line interface / Commands
  • The composer.json Schema
  • Repositories
  • Config
  • Community


Packagist is the main Composer repository. It aggregates public PHP packages installable with Composer.