"In the same way that Blogger made it easy to create a blog, Google App Engine is designed from the ground up to make it easy to create and run web applications," wrote Kevin Gibbs, a tech lead for Google App Engine, on the company's corporate blog.

Developers can use the same building blocks that Google uses, such as Google File Systems (GFS), a scalable distributed file system for large distributed data-intensive applications, and Bigtable, a distributed storage system for managing structured data that is designed to scale to a very large size: petabytes of data across thousands of commodity servers, according to Gibbs.

Many projects at Google store data in Bigtable, including Web indexing, Google Earth, and Google Finance, according to the company.

App Engine "provides access to scalable infrastructure that we hope will make it easier for developers to scale their applications automatically as they grow. This means they can spend less time dealing with system administration and maintenance, and more time building and improving their applications," Gibbs said.

The tool is free to use to the first 10,000 developers that sign up during a preview release but Google cautions that the amount of computing resources is limited. "In the future, developers will be able to purchase additional computing resources as needed, but Google App Engine will always be free to get started," Gibbs wrote.

During the preview, applications are limited to 500MB of storage, 200M megacycles of CPU per day, and 10GB bandwidth per day.

"We expect most applications will be able to serve around 5 million pageviews per month. In the future, these limited quotas will remain free, and developers will be able to purchase additional resources as needed," wrote Paul McDonald, Apps Engine product manager at Google in another blog post.