AppSource is a software-development firm and Software-as-a-Service (SaaS) provider. It builds applications to help companies manage specific business functions and then hosts them in third-party data centers. Customers access their applications through a browser and AppSource charges them a monthly fee. Since 2008 AppSource has expanded steadily and now provides a range of applications, all delivered through the SaaS model. These include: Restobot, a tool to help restaurants manage their business processes; Trippingbot, a booking system for travel and ferry companies; and Terrabooks, a ledger-management system for accounts departments.