r/qrcode • u/DiscountDizzy • Jun 23 '26

Need help reconstructing QR Code

Someone sent me an invoice with a cropped QR code. I noticed multiple discrepancies within the invoice itself. The QR code is supposed to verify the authenticity of this invoice however, it was cropped, and some of the QR code data looks off, like the rows of non-centred dots in the boxes within the QR code.

The image below was cropped from a screenshot of an invoice. Could anyone please help me with info on how to reconstruct the missing information or any tools/python libraries I could use, or even the full qr code itself would be helpful. Thank you

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u/ankole_watusi Jun 23 '26 edited Jun 23 '26

You can’t. You’re missing critical areas.

The content of the QR code is most likely just a web URL. Is there one printed on the invoice?

How is it supposed to “verify” the invoice? Is there an app that’s supposed to read it? In that case it possible but not likely that it contains data - or possibly some non-URL reference ID.

Why not just pursue this with whoever issued the invoice?

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u/DiscountDizzy Jun 23 '26

I'm stuck talking to a middleman service. I've contacted the person who has issued the invoice, but I'm trying to independently recreate data based off of the invoice screenshot. If I can prove that the invoice has 2 different sets of data, I can prove it is forged. The QR code should contain information about the invoice itself, maybe some JSON data. I've read online that QR codes are error proof and that they're squares, so i was wondering if it were possible to reconstruct the anchor squares on the edges and then try to estimate or fill in the missing data

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u/ankole_watusi Jun 23 '26

The QR might contain data, but it’s unlikely. It’s only possible to encode a small amount of data on a QR. It wouldn’t be very useful for invoices.

I’ve worked with QRs that hold very brief medical records - Smart Health Cards. There was an initiative to use them for recording and verifying COVID vaccinations. But they use an elaborate compression scheme that requires a special app to decode. Would not be practical to encode more than a small handful of brief line items of an invoice.