We keep the least data the app can run on: your email (to sign you in and recover your diary), your profile numbers (so calories can be calculated), and the food you log. That's it.
There are no advertising trackers, analytics beacons, or cross-app SDKs in Fuelcairn. No ad code exists in this app at all, so there is nothing to "anonymise".
Passwords are stored salted and hashed (PBKDF2-SHA256). Session cookies are HttpOnly and expire after 30 days, so you are not force-logged-out the way reviewers complained about elsewhere.
Your diary lives on our servers (Cloudflare D1) so it follows you across devices. Export it as CSV any time from Profile, and delete your account to remove it.
Barcode lookups send only the barcode number to the open Open Food Facts service. No account identifiers travel with a scan.