What kind of NFC tag should I buy?
Any NFC tag, sticker or card that can hold a URL works (NTAG213 and similar). Get a commercial one yourself.
Which phones can write a tag?
Writing works only from Chrome on Android. iPhone cannot write, but it can read a tag.
Can I change things after writing?
You can edit your card page in the dashboard at any time. The URL on the tag does not change, so there is nothing to rewrite. To overwrite the tag itself, write it again the same way. We do not lock the tag.
How is it different from a QR code?
Both open the same card page. With QR, the other person scans your screen with their camera. With NFC, they just hold their phone to the tag.
Do you sell tags?
No. You use a commercial NFC tag. Your card page and exchanges are free.
What if it will not write?
If the "Write to an NFC tag" button does not appear, your browser does not support NFC writing. Open the page in Chrome on Android. If a write fails, hold the tag again or try another tag.