Google's App Engine hosted development environment has been upgraded to allow applications to exchange instant messages with networks based on the XMPP open standard.

The support for XMPP (Extensible Messaging and Presence Protocol) is part of the latest upgrade to the App Engine software development kit for the Python and Java programming languages, said Google.

The new XMPP API will allow applications built and hosted on App Engine to communicate via IM with users of services like Google Talk and of others whose networks are based on XMPP, also popularly known as Jabber.

Google plans to extend the IM functionality beyond the exchange of text messages to other areas, like the recognition of users' status, also known as IM presence.

In addition, version 1.2.5 of the App Engine SDK also adds a task queue API for Java applications, something that already existed for Python applications.

Another new feature is an App Engine launcher for Windows, which the product already had for Mac OS X. The launcher is designed to simplify the creation, local testing and uploading to App Engine servers of Python applications, according to Google.

"In addition, we're releasing the source code for both Mac and Windows App Engine Launchers as open source projects," reads the Google blog posting.

App Engine, introduced in limited availability in early April of 2008 and opened up widely about a month later, isn't intended to be a hosted development environment for all types of applications and developers.

Instead, Google designed App Engine for the types of applications the search company develops, namely web applications with mass appeal that don't require long-running processes to, for example, crunch scientific data.

App Engine's sweet spots are database-backed web applications like blogs, office productivity programs and social-networking tools.

Unlike other hosted computing and development services, like Amazon's AWS, App Engine offers developers a tightly integrated set of components, which reduces the tuning and configuring that developers must engage in.

While this design sacrifices flexibility and control by reducing options, it is in line with App Engine's goal of appealing to developers who want to create and deploy applications quickly, relying on Google to handle the rest.