Privacy policy
Last updated 24 September 2026
Demijohn is a batch log. We store what you type into it so it shows up on your other devices, and as little else as the service needs to run.
Who we are
Demijohn is operated by the Demijohn team ("we"). Contact: hello@demijohn.app.
What we store
- Account: e-mail address, display name, sign-in method (e-mail and password, Apple or Google), time zone and language, notification preferences.
- Your log: batches, readings, events, recipes, reminders, cellar items, tasting notes, hydrometer devices and the readings they send, photos you upload.
- Devices: a push token per installation so reminders reach the right phone, plus platform and app version for support.
- Subscription: status, plan and renewal dates as reported by RevenueCat. We never see card numbers; Apple and Google handle payment.
- Technical: server logs with IP address and request path, kept for 30 days, used for abuse prevention and debugging. Error reports without personal data.
What we do not do
- No advertising, no ad identifiers, no selling or renting of data.
- No tracking across other apps or sites.
- No reading of your notes for any purpose other than showing them to you and the people you share a batch with.
Sharing you choose
A batch is private until you turn on its public page or invite household members. A public page shows the batch name, style, readings, timeline and, if you allow it, the recipe. It never shows your e-mail. You can switch it off at any time; the address stops working immediately.
Processors we rely on
- DigitalOcean (EU region): application server and database.
- Cloudflare R2: photo and export file storage.
- RevenueCat: subscription status from the App Store and Google Play.
- Firebase Cloud Messaging: delivery of push notifications.
- Resend: transactional e-mail (sign-in codes, invitations).
- Apple and Google: sign-in and payment, under their own policies.
How long
As long as you have an account. When you delete it, everything is erased after a 7-day grace period (see deleting your account). Backups roll over within 30 days.
Your rights
You can export everything from Settings → Export data, correct anything in the app, and delete the account yourself. For anything else, including access or objection requests under the GDPR, write to hello@demijohn.app. We answer within 30 days.
Children
Demijohn is for adults of legal drinking age in their country. We do not knowingly keep accounts of minors; tell us and we remove them.
Changes
If this policy changes in a way that matters, the app tells you before the change applies. Earlier versions are available on request.