This document provides an overview of software as a service (SaaS). It defines SaaS as software delivered as a service online through the cloud and on a subscription basis. Key aspects of SaaS include software being hosted on servers and accessed via a web browser or thin client, with monthly billing and automatic updates handled by the provider. Benefits of SaaS for customers are lower upfront costs, easy access from any device, automatic backups, and maintenance handled by the provider. The global SaaS market is projected to reach $112.8 billion by 2019.