Backstamp

Privacy Policy

Last updated 8 August 2026

Backstamp is built to need as little about you as possible. There are no accounts, no sign-up, no advertising, and no analytics or tracking SDKs. Most of the app runs entirely on your device.

The short version. The marks library and the decoder work offline on your phone. Nothing leaves your device unless you photograph a mark and ask us to read it — and that photo is used to produce a transcription, then discarded. We never sell or share your data, and we do not track you across apps or websites.

What we collect

Data	Why	Kept?
A random install identifier	Enforces the free-tier daily scan limit. Generated on your device, not linked to you, not an advertising identifier.	Until you delete the app
Photos you choose to scan	Sent to our server, read by an AI model to transcribe the mark, then discarded.	No. The image is not stored.
A one-way hash of the image, and the resulting text	Cached so the same mark isn't re-processed. A hash cannot be turned back into your photo.	30 days
Purchase status	Tells the app whether you have an active subscription.	Managed by Apple and RevenueCat

What stays on your device and never leaves it

Your ledger of finds — every mark, what you paid, and the estimated range
The full marks library and the field guide
Every decode you make by typing a mark rather than photographing it

Typing a mark instead of photographing it involves no network request at all.

Who else is involved

Service	Role
Anthropic	Processes scan images to transcribe the mark. Images sent via the API are not used to train models.
Cloudflare	Hosts the service that holds our API credentials, enforces scan limits and stores the hash cache.
RevenueCat	Validates subscription receipts and tells the app what you're entitled to.
Apple	Processes all payments. We never see your payment details.

What we never do

Sell or rent your data to anyone
Track you across other apps or websites
Show advertising, or share data with advertisers
Ask for your name, email, phone number or address
Access your photo library beyond the specific images you pick

Children

Backstamp is not directed at children under 13, and we do not knowingly collect information from them. There is nothing in the app that asks for personal details.

Deleting your data

Delete the app. That removes your ledger, your install identifier and every local setting. The 30-day image-hash cache expires by itself and contains nothing that identifies you. To cancel a subscription, use your Apple ID subscription settings.

Availability

Backstamp is not offered in the European Union or the European Economic Area.

Changes

If this policy changes materially we'll update the date above and note the change in the app's release notes.

Contact

Questions about privacy: privacy@backstamp.app