How secure are my data?
Your data are stored only locally on your phone. You can optionally make backups to your private Google Drive space or iCloud.
Data stored in the app's private directories are not accessible by any other apps or processes. You (or anyone else) even can't download the data from the app even if you connect your phone to your computer.
Your backups are transferred to the Google Drive or iCloud via the secure (encrypted) channels. All data stored on the Google Drive are encrypted by Google, data on iCloud are encrypted by Apple.
The most important thing is that only Daylio app is able to read your entries. We don't send your data to our servers so we don't have the access to your entries. Also, any other third party app can't read your data.