Google has updated App Engine to 1.4.3. The new version adds:

Prospective Search API for Python – this lets you register a large set of queries which are executed against a flow of data so you can create notifications or other actions whenever a match is found.

Testbed Unit Test Framework for Python – this lets you create stubs for Google services for lightweight unit tests.

Concurrent requests for Java – a single application instance can now serve multiple requests provided it is marked threadsafe. An important feature.

Java Remote API – the remote API lets you access an App Engine datastore from your local machine.

I have had the sense that Google App Engine is more attractive to start-ups and small organisations than to enterprise customers. It is interesting to see Google working on bringing the Java and Python runtimes closer to parity, as Java is more widely used for enterprise development.

Another initiative aimed at enterprise customers is App Engine for Business, currently in preview. What you get is:

An Enterprise Administration Console console for managing all apps built by your company, with access control lists.

99.9% service level agreement

Hosted SQL:

While many applications can be built on the App Engine Datastore (which uses Google’s BigTable database system), we know SQL is the industry standard for the enterprise, so we’ve got you covered. SQL database support on App Engine gives enterprise developers access to the full capabilities of a dedicated relational database, without the headache of managing it.

SSL to an URL that uses your domain, such as https://myapp.apps.example.com.

Pricing – $8 per user up to a maximum of $1000 per month. In other words, if you have more than 125 users the cost per user starts coming down; if you have 1000 users it is a bargain.

Has Google done enough to make App Engine attractive to enterprise customers? This post from a frustrated developer back in November 2010 complained about stability issues and other annoyances that do not really exist on Amazon or Microsoft Azure; the Salesforce.com platform does have some throttling limitations. But it does seem that Google is determined to address the issues and App Engine for Business looks promising.