In the previous chapter, you discovered that Laravel is built on top of several third-party packages. Rather than including these external dependencies in its own source code, Laravel uses a dependency manager called Composer to download them and keep them up to date. Since Laravel is made up of multiple packages, they too are downloaded and installed each time you create a new Laravel project.

Strongly inspired by popular dependency managers in other languages, such as Ruby's Bundler or Node.js's Node Package Manager (npm), Composer brings these features to PHP and has quickly become the de facto dependency manager in PHP.

A few years ago, you may have used PHP Extension and Application Repository (PEAR) to download libraries. PEAR differs from Composer, in that PEAR would install packages on a system-level basis, whereas a dependency manager, such as Composer, installs them on a project-level basis. With PEAR, you could only have one version of a package installed on a system...