Google App Engine

App Engine is a free hosting service offered by Google with services and tools for developing web applications more easily.

As a first step, the service was provided free of charge on a trial basis to 10000 users with limitations in resources, in space and traffic volume permitted.
For example, 5 million page views per month maximum, and to go beyond, you have to pay.

Advantages of App Engine

Google provides the resources, we can then create a Web application focusing on the services of the application itself and without having faced annexes such as hosting and traffic.

The service allows to evolve by adapting resources, including space and traffic volume without it is necessary to restructure the application. Traffic spikes are handled without any problem and anything to change.

The APIs provide predefined components that you will no longer need to implement, such as user authentication, and better integration with the services provided by Google, such as Maps.

Several language are supported including Java.

Disadvantages

There is always a risk to rely on an outside service to an online application. The experience of this user whose domain has been disabled by mistake, and who spent days trying to reach someone who can solve its problem, demonstrates it. There is support, but since his account was disabled, it could not be accessed. The PIN number which is required is regularly updated, so we can not write it down.

The PHP language is not directly supported. But it may be used through Quercus.
In the same vein, data storage is done on the BigTable service and not MySQL that is familiar to webmasters.

Some webmasters have pointed to the conditions of use, they give extended right to Google on the content stored on App Engine. But Matt Cutts pointed out that this license is used primarily to protect Google against all eventualities and not against developers.

Update May 2013: PHP is now supported directly. You can use Wordpress on App Engine now. But to do this, a MySQL database it still required. For this we must use the SQL Cloud service recently created by Google.

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