You cannot cut the corners off a QR code: the three big squares in the corners are what the camera looks for first. So a round QR code is really a square code with a circular field of decorative dots around it. Done carelessly, those dots touch the code and confuse the decoder. Here they never enter the quiet zone, the clear band the standard requires around the grid, and they are drawn smaller than real modules so a reader can tell them apart.
The same construction gives you hearts, hexagons, shields and organic blobs in the Frame tab. Decoration density sets how full the ring is, Reach how far it extends. Round codes read well because the actual code is untouched, which the scan check confirms.
Round codes suit stickers, coasters, badges and social avatars. Cut a circular sticker to the outer edge of the dots and the code looks made for it.
Questions
Do round QR codes scan?
Yes, as long as the square code inside is whole and the ring of dots stays outside the quiet zone, which is how this generator builds them. Codes with the corners actually trimmed do not scan.
Can I make a heart-shaped QR code?
Yes, pick Heart under Outline shape. The code sits in the upper part of the heart and the dots fill the rest.