I have a vendor who provides API’s for each product they sell to us in JSON Rest. Is this possible to integrate with Infusionsoft?
The source (the vendor’s API is the key component). If you have access to a working api for the third party app then the IS API/REST can be used to send it into your app. The only other major concern would be to be sure that what you want to carry over into IS is something that is mappable to how information is stored in IS. Generally, however, it would not be a problem (we do custom integrations every day so I can tell you that most of the time that’s not an issue but should be assessed just the same)