Surface guide
QR codes on email signatures
A QR code in an email signature is scanned from a second device (someone photographing their own screen), so size it in pixels: 80–120 px displayed, exported at 2× for retina. Most email clients block images by default, so a text link is still required.
| Typical scan distance | screen |
|---|---|
| Minimum code width | 80–120 px |
| Error correction | M |
Images are blocked by default
Outlook, Gmail and most corporate clients block remote images until the reader clicks show images. A signature that depends on a QR code is a signature that usually shows a broken-image box. Always include the plain text link.
Sizing for screens
Display at 80–120 px. Export at 2× (160–240 px) and set the display size in HTML, so the code stays crisp on high-DPI displays.
<img src="…" width="100" height="100" alt="Scan for my contact details">
Embed, do not hotlink
Base64-embed the image (data: URI) or attach it inline (cid:). Hotlinking to an image
on your site means every open leaks a signal to your server and breaks entirely if the file
moves. Some clients strip data: URIs, so cid: inline attachment is the most reliable.
Alt text
A QR code is invisible to a screen reader. alt="Scan for my contact details" is the
minimum; the text link beside it is what actually serves those readers.
Keep it modest
A signature block with a 200 px QR code, a logo and three social icons is why people mute threads. One small code, one line of text.