I am currently developing a SharePoint 2013 solution that uses ExCM 2013. Is there an API that exposes some of the functionality of ExCM to work with it programmatically? I am specifically looking at adding roles to ExCM programmatically.
The database that stores the Extranet Users and Roles is a SQL Server database whose schema was developed by Microsoft as part of ASP.NET. They also provide classes in ASP.NET for manipulation of the database. In fact, those classes are what our product uses to read and write to the database.
So, you could certainly write a custom program to access the database and read and write data to it. You would just need to remember that it is also being used by SharePoint and our add-on and you want to be careful not to break anything that those two pieces of software are looking for.
You should be able to do a search for something like ASP.NET SQLMembershipProvider or something like that on MSDN and find the documentation on the schema and classes.
Hope this helps,