This is fairly raw functionality so far, but it is now technically possible to import and export data. Every type of data you put in Cassette Nest can be exported separately into its own CSV file.
Some of this work remains behind a feature flag until I can polish it up a bit more (at the time of this update, it was all behind feature flags and only available to yours truly). While it is possible to import every bit of data back into the system, depending on the order you do it and whether or not your account is empty, it can be a bit fiddly.