API key accessible in the Dasboard > Collections > License. It is also present in the config.xml file.
field is the field from which the related search terms are to be fetched eg: content, keywords, title, description or custom meta field
whether it is phrase or fuzzy search for related terms
AND or OR operator between the terms if multiple words are available in search term
number of related queries returned
number of associated terms returned for each query
Try It!to start a request and see the response here!