AppsFuel API system is a standard Oauth2 implementation. It allows developer for gathering information about User, including appsfuel unique id and the user paid status. This service is available at runtime through the API REST service at the address https://api.appsfuel.com/ We give you the chance to setup your integration with Live or Sandbox environments. Sandbox (aka staging area) lets you test your integration without doing any type of real payment. Instead Live (aka production) is the real environment. That means real paywall process flow and payment. You can choose the environments simply changing the api endpoint url from the following:
Sandbox: https://api.appsfuel.com/v1/sandbox Live: https://api.appsfuel.com/v1/live
For the complete reference http://docs.appsfuel.com See an example at https://gist.github.com/allevo/9737027