Read a QR code from an image

The reason to decode before you tap

A QR code is unreadable by humans by design. That is the whole security problem: you cannot see where a code goes until you have already gone there. Fraudulent codes stuck over legitimate ones on parking meters, charging points, restaurant tables and utility bills exploit exactly that gap.

Decoding first closes it. Paste the code, read the destination, then decide. Cases where it is worth the extra ten seconds:

• Any code that asks for a payment or a login.
• Codes on public infrastructure — parking, chargers, ticket machines — where a sticker can be applied by anyone.
• Codes arriving by post or email claiming to be from a bank, a tax authority or a delivery company.
• Codes on a package you were not expecting.
• Any code where the destination domain is the thing you are being asked to trust.

Proofing codes before a print run

The other use is quality control. Export your code, scan the file back here, and confirm the payload is byte-for-byte what you intended. This catches:

1. Typos in a URL that you have read past five times.
2. Wi-Fi passwords broken by an unescaped semicolon.
3. vCard fields that silently truncated.
4. Wallet or account numbers altered by clipboard malware between copy and paste.
5. Codes that were resized or compressed into unreadability by a layout application.

For a print run of any size, this is a two-minute check that prevents an expensive reprint.