Microsoft today announced that they will enable apps in Outlook.com from Spring 2015. Outlook.com will support third-party apps that will allow users to be more productive than ever. This is also a great opportunity for developers as their apps can reach 400 million active Outlook.com customers. Last year, Microsoft announced Office 365 platform for developers which allowed developers to build apps on top of Office 365 platform for the enterprise customers. Microsoft is now bringing the same APIs to Outlook.com. Developers can now start building apps for Outlook Web App in Office 365 and it will work with Outlook.com.
For Outlook.com customers, these apps can be used in any browser without plugins or extensions, and will be available wherever you log in.