Glossary
Decode-verify
Decode-verify is the practice of reading a generated QR code back with a real decoder before shipping it. It is the only way to know that a styled, logo-bearing or heavily coloured code actually scans, rather than assuming it does.
Why generators skip it
It costs work. Rendering a matrix is straightforward; rasterising the result and running a decoder over it is a second pipeline. Most tools render and hope, and push the risk onto whoever prints the code.
What UseQR does
Every code is rendered to SVG, rasterised, and read back with ZXing — in the browser before you download, and in CI for every permutation of module style, eye style, gradient, logo coverage and error-correction level. A permutation that fails is a build failure, not a customer complaint.
What it cannot tell you
Decoding a clean digital raster is a necessary condition, not a sufficient one. It does not model ink spread, glare, motion blur, or a camera at 40°. That is what the validator and a physical proof print are for.
Related
- ZXing — ZXing — "zebra crossing" — is the open-source barcode library that most QR decoding is ultimately built on. UseQR uses a WebAssembly build of it to…
- Contrast ratio — Contrast ratio is the luminance difference between a QR code's dark and light modules. Decoders need a clear threshold; the practical floor is about 40%…
- Error correction level — Error correction level sets how much of a QR code can be damaged and still decode: L tolerates about 7%, M 15%, Q 25% and H 30%. Higher levels cost…