Sanctum does not collect your personal data. The lines you keep, the topics and collections they're filed into, and your settings are stored on your iPhone. They are not sent to us. We have no servers that receive your lines, and we cannot see them.
There is one small exception, and we'd rather tell you than trick you: book and author lookups, explained below. And two things you may choose to do yourself: hand your words to another AI, or send a collection to a friend. Both are explained here too.