try one of the following extensions
- Get all TinyDB Extension by Juan Antonio to backup TinyDB as Text or JSON format
- ETinyDB: Extra utilities for Tiny DB Extension by Kumaraswamy_B.G
- TinyDBBackup Extension by Riad_Developer
- SuperTinyDB Extension by rasitech
taken from the extensions directory at App Inventor Extensions | Pura Vida Apps
Taifun