Integrate 3rd Party API with existing PHP app using cURL

We have an existing web service that we post form-encoded data to. This service does some minor parsing of the data it receives and makes some small changes to the original form-encoded data and creates cURL post that gets forwarded elsewhere. We can only parse data in this service currently. For certain data, we need to add the ability to make a call to a 3rd party API to get some additional info . This project is for creating an OOP class in PHP that accepts as input a deal id and returns an array of strings. This class will need to make a web service call to an API. The 3rd party we are working with is pipedrive.com. You can sign up for a free trial and go to "Settings" -> "API" to get your API key, which can be used to test in this site: [login to view URL] The name of the function you will need to use is "List products attached to a deal" or "/deals/:id/products". This is a very straight forward intro project that only addresses one of many tasks. If this project ends in success we can talk about adding other functions and other 3rd part web service integrations.