An active user means someone logging into your product in any given month. If the same user logs in multiple times, we count them as one active user. We don't charge you for dormant users who may be in your database but don't log any activity during a given month. If you have a lot of guest users (ie. prior to log-in), reach out to us for a custom quote. We use this as part of our pricing because our costs are proportional to the number of users we need to track and maintain data for, and the number of API calls we need to make.