QR Code Generator

What it does

Encodes any text or URL into a QR code using a complete, from-scratch implementation of the ISO/IEC 18004 standard: all three data modes (numeric, alphanumeric, byte — picked automatically for the tightest fit), versions 1-40 (21×21 up to 177×177 modules), all four error-correction levels, Reed-Solomon error correction over GF(256), and automatic mask selection across all eight ISO mask patterns. Output is a crisp SVG (any scale, colors, quiet-zone size) or a PNG rendered at the chosen module size.

The encoder is verified against a published reference matrix, and everything runs locally — your text never leaves the page.

How to use

1. Type or paste text into the box.
2. Pick an error-correction level: L is smallest, H survives the most damage.
3. Adjust module size, quiet zone and colors.
4. Download the PNG, or copy the SVG markup to scale losslessly.

The page URL carries your full setup (text, level, colors, sizes) — Copy share link reopens it exactly.

Examples

https://dev.cosmolabs.org/ at level M encodes as version 2, byte mode. HELLO WORLD at level Q encodes as version 1 in alphanumeric mode — 11 characters fit because alphanumeric packs two characters per 11 bits.

Long content grows the version automatically: up to 2,953 bytes at level L.

Good to know

• Higher error correction costs capacity: the same text grows a bigger symbol as you move from L to H.
• The quiet zone (light margin) is part of the spec — keep at least 4 modules for reliable scanning.
• Dark-on-light contrast matters more than colors: keep the foreground clearly darker than the background.
• SVG output scales infinitely; PNG rasterizes at the chosen module size.