Instances make Mastodon links long — codes make them one scan
The fediverse's great strength is also its addressing problem: your identity is @you@some.instance, and the web address depends on which server you joined. Written on a poster, that's two @ signs and a domain most people have never typed before. A QR code removes every character of it.
This page defaults to mastodon.social because it's the largest instance. If you're anywhere else, switch to "Any link" and paste your full profile URL — the code works exactly the same, and scanning still lands anyone on your profile regardless of which server they use themselves.
Worth knowing for print: a profile URL keeps working even if you migrate instances, because Mastodon leaves a redirect on the old account. It's not permanent, though, so treat a migration as a reason to reprint rather than a guarantee.
Every Mastodon code made here is static: the link lives in the pattern itself, with no redirect service in the middle that can expire, start charging or go down. There's no account, no watermark and no scan limit — download it once and it keeps working for as long as the Mastodon link behind it does.