The Riffyn SDE API (Application Program Interface) is a RESTFUL web API for programmtically interacting with Riffyn. You can use virtually any programming language to read and write data to Riffyn this way. You can find a brief intro to the API and some examples here.
Riffyn SDE AddIns are built on top of this API. You can extend Riffyn capabilities in the same way with your own programs interacting with the API.
Please visit https://api.riffyn.com (or equivalent for your VPC) for full API documentation and SDKs for eleven languages.