Privacy policy Draft

This is a plain-language draft that describes how Syntropium works today. It is not yet in effect and will be reviewed before Syntropium opens to the public. Where something is not decided yet, it says so.

Draft of 26 October 2026. “Syntropium”, “we” and “us” mean Sunergeo Systems, which makes Syntropium. “The app” means the Syntropium web app at app.syntropium.app and the Syntropium iPhone app.

In short

Without Premium, your catalog and photos stay on your device. We receive none of it.
With Premium, your catalog and photos are encrypted on your device before they reach us. We cannot read them and cannot decrypt them.
We don’t use analytics, advertising or tracking, in the app or on this website, and we don’t sell or share data about you.
Our sync service holds no name, email address or password for you.

1. Using the app without Premium

Everything you enter — containers, items, descriptions, tags, quantities, value estimates and photos — is stored on your device only: in your browser’s storage for the web app, or in the app’s storage on iPhone. It is not sent to us. You don’t create an account.

To load the web app, your browser requests its files from our web server, which, like any web server, receives your network (IP) address and browser details with each request. See server logs.

2. Using Premium sync

When you turn on Premium, our sync service stores:

Your encrypted catalog and photos. Encrypted on your device with a key we never receive. We can’t read their contents or see how they relate to each other.
A random account ID that identifies your account. It is not linked to your name or email address in the sync service.
Device records: the public part of each device’s passkey, the device name you see in your device list, when it was added and last used, and your encryption key in a wrapped form that only your passkey can unwrap.
Account records: subscription status, how many things and how much storage your account uses, and when it was created and last active.
Session records: for each signed-in session, the network (IP) address and browser or app version it reported, kept for security (see retention).
Messages to you shown in the app’s notifications.

From the encrypted data, we can unavoidably tell how many things you have, their approximate sizes, and when they change and sync. We don’t use this for anything except running and protecting the service.

3. Email addresses and payment

During the beta no one is charged. Beta invitations are issued through a small billing service that we run on our own server, separate from the sync service. It stores the email address the invitation was sent to and the state of the complimentary subscription.

When Premium goes on sale, payments will be handled by a payment provider acting as the seller (we intend to use Lemon Squeezy). It will hold your email address and payment details under its own privacy policy, and send messages about your subscription. We will receive your subscription status and a customer reference, not your card details. This section will be updated, and the provider named, before that happens.

4. What we never collect

The readable contents of your catalog or photos.
Your encryption key, your passkey, or a password (there is none).
Your name, phone number, contacts or location.
Analytics, advertising identifiers or usage tracking.

5. How we use what we hold

Only to provide sync to your devices, keep your account secure, enforce plan limits, and send you messages about your account. We don’t sell, rent or share it for advertising, and we don’t use it to build profiles.

Payment provider (from when Premium goes on sale), as described above.
Legal requests. If we are legally required to provide data, we can provide only what we hold: encrypted data we cannot decrypt, and the records listed above. We intend to publish a yearly transparency report about such requests.

We don’t use other third-party services that receive your data.

7. Where it is stored

Our servers are in the United States. If you use Syntropium from elsewhere, your encrypted data is transferred there. Undecided: the legal mechanism we will rely on for transfers from the EU, UK and similar regions.

8. How long we keep it

As currently built:

Deleted things. When you delete something with Premium on, the server keeps an encrypted “deleted” marker for 90 days so your other devices learn about the deletion, then removes it.
Photos. An encrypted photo that nothing refers to any more is marked for removal after 7 days and deleted 30 days after that.
Sessions. Session records, including network address, are deleted automatically, at the latest about three months after the session ends.
Notifications. In-app messages are dismissed after a year and deleted about three months later.

Undecided: how long data is kept after a Premium account is deleted or a subscription ends; how long our encrypted server backups are kept; and how long web server logs are kept. Until there is a delete button in the app, you can ask us to delete your Premium account by email.

9. Server logs

Our web servers record requests (such as the address requested, the time, your network address and browser details) to keep the service running and secure. Server logs never contain your catalog or photos in readable form. Undecided: the retention period for these logs.

10. Your choices and rights

Export everything at any time from the app’s Settings.
Clear all data from a device in Settings.
Turn sync off on any device, or remove a device from your account.
Ask us what we hold about your account, or ask us to delete it, at hello@syntropium.app, including your account ID. Because we don’t know who you are, the account ID (or your passkey) is how we confirm the account is yours.

Depending on where you live, you may have further rights under laws such as the GDPR or state privacy laws. Undecided: the exact statement of those rights for the final policy.

11. Security

Encryption happens on your device; we hold no key that can decrypt your data, and there is no recovery mechanism. If you lose every device and your passkey account, your synced data cannot be recovered by anyone. See Privacy & trust.

12. Children

Syntropium is not directed at children under 13, and Premium is for adults or people with their parent’s or guardian’s permission. Undecided: the final age wording.

13. Changes

We will post any change here with its date before it takes effect, and tell Premium users in the app about material changes.

14. Contact

Sunergeo Systems — hello@syntropium.app.