Contextual Merchandising is supported on the Item-based Recommendations family widgets. It works similarly to Item-based recommendation widgets and uses the Product ID/Context ID as an identifier for the item on your site to display relevant recommendations.
Contextual Merchandising is applied on the Item-based Recommendations Widget API by passing an additional Context PID (context_pids) parameter (not mandatory).
What is Context PID
Context PID is the latest addition to Item-based recommendations API parameters. Context PID comes into play when a user decides to add a Contextual Merchandising rule as an attribute rule during the widget creation process. An example of a Context PID API parameter is: &context_pids=4500928.
Is Context PID API parameter mandatory?
Currently, the Context PID API parameter is not mandatory. In case a Context PID is not passed as an API parameter, our system will consider Item ID as Context PID and Item ID will work as a fallback for Contextual recommendations.
But it is highly recommended to add a Context PID as an API parameter whenever a contextual attribute rule is added for better widget recall set and performance.