Why this one encodes a search, not a profile
Roblox profile URLs are built from a numeric user ID, not your username — roblox.com/users/1234567/profile. There's no public username-to-profile address, so the honest thing to encode from a username alone is Roblox's own user search, which lands people on the right account in one tap.
If you want the code to open your profile directly, that's easy too: open your profile in a browser, copy the URL with the number in it, then switch to "Any link" and paste it. That's the version to use on anything printed, because it skips the search step entirely.
Groups and experiences work the same way — copy the URL and paste it through "Any link". A group code on a thumbnail, a Discord banner or merch is usually more valuable than a personal profile, since that's where people actually join in.
Everything happens in your browser. The QR encoder is built into this page, so your username is never sent to a server, nothing is logged, and there's no daily limit. The code is static — the link lives in the pattern itself, with no redirect service in the middle that can expire, start charging or go down.