QR codes for the tags you sell
You make the tag — resin, glass, engraved metal, laminate. What decides whether it still works in five years is not only the finish; it is also what the QR code says. Here is what our codes encode, how they are verified, and why you can build a product on them without asking permission.
The failure that lands on your shop
Many free QR generators encode a link by default rather than the phone number itself — a shortened URL that bounces through the generator's own server, or a hosted pet profile on someone else's service. The printed code works exactly as long as that service does. When Google shut down its goo.gl shortener, printed codes that depended on it stopped resolving. When a profile service folds or a subscription lapses, the same thing happens quietly: the tag still scans, and the scan goes nowhere. The buyer discovers this long after the sale, and the review lands on your shop, not on the generator you used.
Contact that lives inside the code
Codes from the tag generator encode the contact information itself, in one of two modes. A tel: code holds a single phone number that dials on scan; it fits in QR version 1 or 2, the chunkiest grid a QR code can have, so it stays scannable at small sizes. A vCard code holds a minimal contact card: the pet's name, up to 40 characters, shown on the finder's phone as "Biscuit (lost pet)"; up to two phone numbers; and a note of up to 120 characters for a medical flag or a reward line. Either way, the finder's phone reads the bytes off the printed square directly. There is no server behind the code, no account, and no subscription — nothing that can expire, fold, or be discontinued. A code you sell keeps working no matter what happens to this site.
Verified before download
Every code is decode-verified by machine before it can be downloaded. We rasterize it at three sizes — 800, 1200, and 1600 pixels — and run each through jsQR, an independent decoder. The download stays blocked until at least two of the three decode to an exact byte match against the content entered. What reaches your printer has been read back, not just generated — the methodology page has the details.
Sizes stated in millimeters
A QR module needs about 0.5 mm to scan reliably, and geometry does not negotiate. On a circular insert the code sits as an inscribed square — side equals diameter ÷ √2 — so a 25 mm disc yields 17.7 mm of code. A square insert keeps 94 percent of its width. In practice: tel: mode fits a 25 mm circle, while a vCard carrying two numbers and a note generally needs 32 mm and up on circles, or a square insert. The generator shows the verdict for each of its 20, 22, 25, 28, 32, and 38 mm presets, and refuses to pretend a loaded vCard will scan from a 20 mm disc.
Insert sheets built for batch work
When an order comes in, the insert sheets tool takes one verified code and lays out up to 60 copies on A4 or US Letter, with hairline cut guides — circle or square — a 12 mm printer margin, and a 6 mm gap between guides. The quiet zone — the four modules of white a scanner needs on every side — is part of the code and sits inside the printed square, so your cut lines never touch it. Each sheet carries a printed reminder to print at 100 percent scale, because a scaled print silently changes every module's size — and the fit verdict was computed for the size you asked for.
What we don't do
We do not make tags, and we do not sell them; you are not feeding a future competitor. We do not take a cut, charge a fee, or require attribution — tags made with these codes are yours to sell. We do not see your customers' contact details: the generator runs entirely in your browser, nothing typed is uploaded or stored, and no accounts exist. And we do not prescribe your method. The insert spec defines what the insert needs and stops there; epoxy, glass cabochons, laminate, and lockets are all your call. The epoxy and resin guide documents one proven method — it is not "the way."
A QR tag is a recovery aid, not GPS. We say this plainly to pet owners, and your listings should too — honest claims age better than a refund request.
Questions makers ask
Can I sell tags made with codes from TagThatPet.com?
Yes. Commercial use is welcome, attribution is not required, and there is no fee and no account.
Will the codes stop working if TagThatPet.com shuts down?
No. The contact information is encoded in the printed code itself, and the finder’s phone decodes it directly — no server is contacted during a scan. Codes already printed keep working no matter what happens to this site.
What insert sizes can I offer?
A tel: code fits a 25 mm circle, which yields 17.7 mm of inscribed code. A vCard with two numbers and a note generally needs 32 mm and up on circles, or a square insert. The generator shows the verdict for every preset from 20 to 38 mm.
Do I have to use epoxy resin?
No. The insert spec covers the insert — size, contrast, quiet zone — and never the encasement. Epoxy, glass, laminate, and lockets all work. The epoxy guide exists because it is one proven method, not because it is required.
Do you see the contact details my customers give me?
No. Everything runs client-side in the browser. Nothing typed into the generator is uploaded, stored, or seen by us, and there are no accounts.