QR codes & printing

leidang's labels are globally unique QR codes minted in batches before anyone decides what they'll be stuck on. Print them, stick them, and bind each code to an item by scanning — registration happens on the floor, not at a desk.

The code

Ten characters of Crockford base32 — no I L O U, so a scuffed sticker can be typed by hand without misreads. Displayed grouped for humans: 7Q4X-K2M9-C3, printed under the QR as a text fallback. The QR itself carries https://go.leidang.app/{code}.

Printed URLs are permanent. Codes are never reused, and voided codes stay dead forever — a sticker in the world keeps resolving for the life of the product.

Mint & export

Mint (QR → Batches, permission-gated): choose a size and a label — "2026 spring sticker run".
PDF label sheets — A4 grids with Avery presets or custom rows/columns, and roll-label single-label pages (25×25, 50×25 mm).
SVG bundle — one vector file per code, for print shops and laser engraving.
CSV manifest — code, URL, batch, position — for your records and the print shop's workflow.

Codes print at error-correction level Q (25% of the sticker can be scuffed, painted, or gaffed over and still scan). Print at 25 mm or larger for arm's-length scanning, and use laminated polyester stickers for gear that travels.

Binding on the floor

Scan an unassigned sticker → the app offers bind to an existing item or register a new item here, pre-filled from the product picker. Multiple codes per item is normal — label big items on several sides, or add a fresh sticker when one wears out without retiring the old binding. Unbinding and re-assigning is permission-gated and lands in the item's history.

Voiding

Lost a sheet of unassigned stickers? Void them. A voided code answers with "gone" at the resolver and can never be assigned — tombstoned, not recycled.