The goal of Microsoft Codename Astoria is to enable applications to expose data as a data service that can be consumed by web clients within corporate networks and across the internet. The data service is reachable over regular HTTP requests, and standard HTTP verbs such as GET, POST, PUT and DELETE are used to perform operations against the service. The payload format for the data exchanged with the service can be controlled by the client and all options are simple, open formats such as plan XML and JSON.
The use of web-friendly technologies make it ideal as a data back-end for AJAX-style applications, Rich Interactive Applications and other applications that need to operate against data that is across the web.

The first Astoria CTP is a dual release, making Astoria available in the form of downloadable bits that can be used to build data services that are entirely contained within a single computer or network and as an experimental online service that you can use to create online stores that are hosted by Microsoft and are accessible over the internet. This September 2007 CTP is mostly a refresh of the past May 2007 that enables developers to use Astoria together with Visual Studio 2008 Beta 2 and the ADO.NET Entity Framework and Tools Beta 2.