qr — render text or a URL as a QR code
SYNOPSIS
qr [-l L|M|Q|H] <text|url> echo text | qr
DESCRIPTION
Encodes the given text (everything after the command) as a QR code and renders it inline as black-on-white blocks, with the standard quiet zone so it scans reliably.
The code is generated entirely in your browser by the command's own encoder (byte mode, UTF-8, versions 1–40) — nothing is sent anywhere. Text can also be piped in.
OPTIONS
-l <level> error correction: L (7 %), M (15 %, default), Q (25 %), H (30 %) — higher survives more damage but is denser
HOW IT WORKS
The text is encoded as UTF-8 bytes, then the command picks the smallest QR version (1 to 40) that fits, adds Reed–Solomon error-correction codewords, places the data in the standard zigzag pattern and applies the mask with the lowest penalty score, as specified by ISO/IEC 18004. The code is drawn with Unicode half blocks on a white card, with the quiet margin scanners need.
USE CASES
- share a URL with a phone in one scan;
- Wi-Fi access (WIFI:T:WPA;S:name;P:password;;), contact cards, e-mail addresses or plain text;
- a code that survives damage or a logo on top: use -l H.
PRIVACY
Unlike many online generators, nothing is uploaded or tracked: the code is computed entirely in your browser.
EXAMPLES
qr https://ludovic.toinel.com qr WIFI:T:WPA;S:MyNetwork;P:secret;;