This is an easy-to-use PHP Composer library for Party And Friends ( Free for Bungeecord, Extended For Bungeecord/Velocity, Extended For Spigot (you need to use MySQL as a data source), or Free For Velocity). You may use it to access data of Party And Friends on your website like who is a friend of whom, or just to know if a player ever joined your server. A little example PHP project which uses this API can be found on GitHub. This project requires PHP 7.4 or later and Composer.

For how to use this API/Library, have a look at the documentation.