Hi! I'm Philipp, the creator of Passion :)
There's no company behind passion, and I don't make money off your data.
I'm an engineer, and I firmly believe that your data is yours and yours alone.
If you have questions, feel free to contact me:
[my first name]@pssn.app
You can use the app without registering at all - the app will ask you about your name, but you can enter whatever you want. (This name will be visible to your partner).
If you decide to register, your email address will be associated with your account.
Your last few messages are being stored on a cloud server in order to enable data exchange between you and your partner, and allowing you to get your messages back if you reinstall the app. The same goes for your (custom) catalogs.
This is exclusively stored with Google (Android) and Apple (iPhone/iOS). The app will check your purchase history on demand in order to determine whether you previously purchased an app upgrade.
Just reset your current space (Settings -> Reset). This will remove your user ID from your shared space.
Note: Deleting individual messages is not yet implemented. I'll probably add this as a feature in the future.