The API Documentation is deprecated because we have moved to JavaScript based installation for LiftSuggest which is easier to set up. Know more about how it works.
API Documentation
A Guide on how you can generate Recommendations.
What does LiftSuggest API do?

The LiftSuggest provides two types of API:

Type1:"Customers who bought this also bought these."
Type2:"Customers who viewed above product ultimately bought these."

LiftSuggest API provides product recommendations for requested product SKU. Once a request is made to LiftSuggest API along with product SKU(s) and other parameters, LiftSuggest API processes the requested SKU(s) and returns the SKUs of the products based on your Google Analytics Data, which are best sold with the requested product for Type1 recommendations and the SKUs of the products which are ultimately bought after viewing the requested product for Type2 recommendations.