And there it is! the ArcGIS Portal REST API documentation was made public today. The API was there all the time of course, but using it needed some detective work using FireBug or your favorite HTTP sniffer.
You can of course continue on that path. You never know what you find along the way. But for those who want to get going quickly developing custom apps on the ArcGIS Online platform, the documentation should come in handy.
We've been using the API in some of our projects (like the gallery in geo.data.gov and the open government data label in geoplatform.gov), Kentucky's KyGovMaps site, and even the integration of Geoportal Server with ArcGIS Online I described earlier is possible thanks to this API. But it doesn't end there. Want to build your site in Drupal or Microsoft SharePoint? Now there's an API for that.
Or if you want to develop a custom application template like this one:
Whether you want to access a group to build your gallery from or do something interesting with the content of individual webmaps, the ArcGIS Portal REST API documentation helps you build your apps.
Perhaps this will now push me to finish up this Drupal module I had started a while ago. OR perhaps someone out there is adventurous enough to help me with that...