packagecloud.io vs Packagist: What are the differences?
packagecloud.io: apt, yum, and rubygems repositories with powerful tooling, security and automation. Install packages with apt-get install, yum install or gem install exactly like you do now. No additional software required. Track, analyze and control access to your packages. Programmatically issue and revoke credentials with our API; Packagist: A default Composer package repository. It is the main Composer repository. It aggregates public PHP packages installable with Composer. It lets you find packages and lets Composer know where to get the code from. You can use Composer to manage your project or libraries' dependencies.
packagecloud.io and Packagist can be primarily classified as "Hosted Package Repository" tools.
Packagist is an open source tool with 1.29K GitHub stars and 392 GitHub forks. Here's a link to Packagist's open source repository on GitHub.