Apaleo is a Property Management System which is purported as an Open PMS. It provides API access to all its users and vendor partners as well as an App rich marketplace where customers can choose from over 200 Apps to improve their PMS.

Cassandra is a free and open-source, distributed, wide-column store, NoSQL database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure.