The official MercadoLibre Ruby SDK by MercadoLibre calls the MercadoLibre RESTful API which provides tools to create an online store. This SDK is used to handle the OAuth WebServer flow, and there is no JSON parsing.
Escrow.com has announced a beta version of its Platform API. Through the API, third party apps and services can integrate the escrow services Escrow.com has long been known for. Once integrated, apps and services can hold money in trust until a transaction has fully completed.