WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.
Bitbucket is a web-based version control repository hosting service for source code and development projects that use either Mercurial or Git revision control systems.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.