What is Google App Engine?
Google App Engine enables you to run your web applications on Google’s Infrastructure, so you don’t have to manage servers and you can directly upload this application & let your end-users use it. Applications developed using App Engine are easy to build and maintain and they are also easily scalable as you traffic and data storage needs grow. Using Google App Engine you can serve your app using your own domain or through a free name on appspot.com domain. You can also limit access to this application only to members to your organization or to the whole world.
With App Engine you only par for the resources your application uses such as storage and bandwidth and it does not include any set-up or recurring costs. Using App Engine you can also control the resources your app can consume. All applications on App Engine can use up to 1GB storage and enough CPU & bandwidth to server around 1 million page views per month for free without and charges, and when you enable billing your free limits are raised & you are charged only for those resources that are above free limits.