The Visitor API requires the Super-Affinity add-on for the Frosmo Platform. To get the add-on, if you do not already have it, contact Frosmo support.
The Visitor API allows you to retrieve visitor affinity data from the Frosmo back end. You can retrieve the affinity profile of a visitor based on their Frosmo ID.
For an introduction to visitor affinity, see Feature: Super-Affinity.