Bessy does not collect or store any data whatsoever about your grades. To be blunt, we have no interest in your grades and couldn't care less about what they are.
The only data we collect is how many people use Bessy (powered by Mixpanel, Visual Studio App Center on mobile, and Splitbee on web) and crash logs (powered by Sentry), which are only sent when a user encounters a bug. The third-party services we use have been heavily scrutinized for best privacy practices (notice how we do not use Google Analytics, for example).
If you have any further questions about your privacy, do not hesitate to use the Feedback feature to contact us. We understand that privacy is a sensitive topic and we want to do our best to be as transparent as possible.