Last updated: 5 August 2026
Bookworth ("the app") is provided by B Chalmers-Stevens ("we", "us"), the data controller for the limited processing described below.
Contact: support@bookworth.co.uk
The app uses your camera to read the ISBN barcode printed on a book. Frames are analysed on your device to extract the barcode number. No image or video is ever uploaded, saved to your photo library, or retained by us. Only the resulting ISBN number is used.
When you scan or type an ISBN, the app sends that ISBN to:
An ISBN is a product identifier, like the barcode on a tin of beans. It says nothing about you. We do not attach a user identifier, account, or profile to these requests, because none exists.
Books you scan are saved locally on your phone. This data is never uploaded to us. It is removed when you delete the app, and you can erase it at any time via Settings → Clear my collection.
If you subscribe, the purchase is processed by Apple. We use RevenueCat to validate the purchase and determine whether your subscription is active. RevenueCat receives purchase information associated with a randomly generated anonymous identifier. We do not provide RevenueCat with your name, email address, or any other identifying information. We never receive or store your payment card details.
Our pricing service records minimal, non-identifying operational information (such as whether a lookup succeeded and how long it took) so we can keep the service working. We do not record your IP address alongside your scan activity, and we do not build a profile of what you scan.
| Recipient | What they receive | Where |
|---|---|---|
| Open Library (Internet Archive) | An ISBN | United States |
| Google Books API | An ISBN | United States |
| Supabase (pricing service host) | An ISBN | London, UK (AWS eu-west-2) |
| Keepa GmbH (Amazon marketplace pricing) | An ISBN | Germany (EU) |
| RevenueCat | Purchase records, anonymous identifier | United States |
| Apple | Payment and subscription data (as its own controller) | Worldwide |
We do not share your data with anyone else, and we do not sell it.
Some services above are based outside the United Kingdom. Where personal data is transferred internationally, we rely on the UK International Data Transfer Addendum to the EU Standard Contractual Clauses, or on the UK Extension to the EU–US Data Privacy Framework where the recipient is certified. Note that the ISBN lookups described above do not contain personal data.
Under UK GDPR you have the right to: access your data; have inaccurate data corrected; have data erased; restrict processing; data portability; object to processing; and, where processing is based on consent, to withdraw that consent at any time.
Because the app has no accounts and we hold no information that identifies you, we are usually unable to link any data to you personally. The most direct way to erase everything the app holds is to clear your collection in Settings or delete the app. To exercise any right, contact support@bookworth.co.uk.
If you are unhappy with how we have handled your data, you may complain to the Information Commissioner's Office (ICO) at ico.org.uk or on 0303 123 1113. We would appreciate the chance to address your concerns first.
No. There is no statutory or contractual requirement to provide personal data, and you do not need an account to use the app. Camera access is optional — you can look up any book by typing its ISBN instead.
Bookworth is not directed at children and we do not knowingly collect data from anyone under 13.
Values shown in the app are estimates generated from third-party online listings. They are not offers, guarantees, or appraisals, and they are not financial advice. Actual selling prices vary by condition, edition, timing, and buyer.
If we change this policy we will update the date at the top and, where the change is significant, tell you in the app.