Build APIs: Prototype, build or scale depending on what architecture phase you are on.
API Cheat sheet helps you to understand the basic differences when building Private, Partner or Public APIs
Private APIs are allowed to be used only by own applications. They contain attributes and data that is business critical and confidential
Partner APIs are available for third-party organizations upon approval of partnership terms and conditions. Partner APIs may contain partner specific or customer data which is not available for general public. Partner is liable for the use of the data according to terms and conditions. The partner may be required to restrict the access of their end-users to the data. For example, a partner may access detailed price and purchase data of all stores but each retailer using partner’s application is only able to access data of their own store.