Why no photo of your cards ever leaves your phone

Most card scanners take a photo and send it to a server that recognises it. It is simple to build, but it means your pictures — and sometimes what is around the card — leave your phone. CardNugget was designed the other way round.

What happens on your iPhone

When you hold up a card, everything that touches the image happens on the device:

1. the camera finds the outline of the card;
2. the image is straightened, as if the card were perfectly flat;
3. the text is read: name, number, set;
4. the card is identified against a catalog of more than 137,000 cards that ships inside the app.

None of these steps needs the Internet. The image is processed in memory and then forgotten.

What goes over the network

Only one thing is needed from the outside world: the price. To get it, the app sends the identifier of the card in its catalog — a short code, nothing more. If the catalog hesitates between several cards, the app sends instead the text it read: number, set, language. Never a picture, never a thumbnail, never anything derived from an image.

Card visuals take the long way round

When you open a card's sheet, the app shows its official visual. It could fetch it directly from the public image server, but that server would then see your IP address and the list of cards you look at. So the request goes through our server, which fetches the image and passes it back. It is slower to build, but nobody else learns what is in your collection.

Where your collection lives

Your collections, quantities and prices are stored on your iPhone and nowhere else. You can delete a card or a whole collection at any time, and uninstalling the app removes everything. There is no cloud copy to forget about.

You can read every detail, including what our server logs, in the privacy policy.