Office Online (previously Office Web Apps) is an online office suite offered by Microsoft, which allows users to create and edit files using lightweight, web browser-based versions of Microsoft Office applications: Word, Excel, PowerPoint and OneNote. The offering also includes Outlook.com, People, Calendar and OneDrive, all of which are accessible from a unified app switcher. The on-premises version of this service called Office Web Apps Server can be installed in private clouds in conjunction with Microsoft SharePoint, Microsoft Exchange Server and Microsoft Lync Server.