Content Glass include an API that developers can use to develop custom Content Glass and State Orineted Sharing applications.
The API can be classified as one of the following:
1. Client API - these are API packages that let developers create Content Glass application on varius clients. Currently we are mainly focus on Web Clinet API, and also have preliminary vewrsion for Android API.
2. Server Widgets - This API can be used to create and manage widgets without a client, by making HTTP REST like calls.
3. Data Services - This class of APIs refer to future APIs that can be used to access the shared information sotred on Content Glass.
A more technical description of APIs can be found of developers website.