Google AppEngine is Google's implementation of the cloud. It is enabled through a SDK in Python and Java. Within AppEngine, common services to run a web application are available, like persistent storage, web transaction management, user authentication, image processing and mail sending through Google accounts.
The AppEngine comes with an SDK which can be installed locally to develop and test web applications. The Python version of the SDK includes Django as web framework, but others may be used as well. The Datastore implements a scalable persistent storage of data, using GL, which is a SQL-like data query and manipulation language. Data schema editing tools are also provided.
AppEngine can be used for free for small applications; larger applications are paid based on resource usage.