The ESME REST API is now available for you to build some cool applications with, checkout this presentation David gave at TechEd for a detailed documentation of the API.
Our API server address for http://esme.us is http://api.esme.us/esme/api/
The ESME team is looking forward to all the cool applications you will build with the ESME API. If you have questions please ask them at our developer discussion group.
