Next Best Action is a paid Salesforce product but also is available for free use for up to 5000 requests each month.
What is a Request and how do they get generated?
A ‘request’ is a call to the NBA engine that causes an NBA ActionStrategy to run and return some recommendations. The primary way these requests are made is via the placement of the Einstein Next Best Action lightning component on a record page in App Builder or via the placement of the Suggested Actions community builder component on a Community page:
Each time a page with an NBA component is loaded into a web browser, a new request will be generated.
The secondary way requests are made is by calling the NBA endpoint from some other piece of software, such as an IOS or Android native app. An app that does this will make requests in response to custom UI, and get back the recommendation information as text that it is then responsible to present.
A request is also made when i) a record detail page includes the Next Best Action component and a record field is updated and ii) when the communities contact support page includes the Next Best Action component as the user types in the subject/description fields.
Where Can I See My Usage?
Look in Setup —> Company Information.
Learn More: Try out Next Best Action via this video tutorial.