This document provides an overview of developing applications for SharePoint Online. It discusses the SharePoint Online offerings, key limitations of developing in this environment including restricted file system access and code limitations. It also outlines techniques for overcoming limitations such as using client-side scripts instead of server-side calls and deploying business logic to Windows Azure. The document recommends getting started with a free Office 365 trial and using Visual Studio tools and FxCop rules validated for the SharePoint Online environment.