Urturn provides a RESTful interface to the resources of urturn e.g. posts, users, etc.
This is NOT the API used to create urturn expression. If you are looking for API used in expression, visit the following project Urturn-expression-api
This project contains the document of the API and a javascript library that help you use this API from a web page. If you want to use the API on the server side you can just use your preferred language and do HTTP request on the API Endpoints.