Google App Engine

Google Inc.

Google offers developers the opportunity to share the same infrastructure is uses for its search engine and other services with Google App Engine.

Applications can be run off Google's servers for free with additional computing time made available by a "budget" -- if use of the app exceeds the budget, the app doesn't run.

App Engine is setup to support web-based applications written in Java or Python. There are a number of restrictions that limit its appeal for enterprise-wide applications. For example, an app can only access other computers on the Internet through the provided URL fetch and email services; other computers can only connect to the application by making HTTP (or HTTPS) requests on the standard ports. Apps cannot write to the file system. An app can read files, but only files uploaded with the application code. The app must use the App Engine datastore, memcache or other services for all data that persists between requests.

Python apps can be developed using the Google App Engine SDK which includes Django but the only language supported is Python 2.5. A Java SDK provides a Java 6 runtime environment.