qrcody

Standalone Python port of qrcody's styled QR code SVG rendering engine — square/rounded/dots/blob/bars/squircle pixel styles, styled finder eyes and pupils, gradients, and framed export (perimeter / scan-me / scan bands). No browser, no server — pure functions in, SVG string out.

This is a hand-port of src/lib/buildSVG.js from the qrcody web app. The rendering logic itself has no DOM dependency in the original (it already runs inside a Cloudflare Worker), so the two implementations produce visually equivalent output, though exact numeric string formatting may differ slightly (e.g. 500 vs 500.0) — SVG renderers treat these identically.

Install

uv add qrcody
# or, for PNG export too:
uv add "qrcody[png]"

PNG export uses cairosvg, which needs the native Cairo library installed on the system (brew install cairo on macOS, apt install libcairo2 on Debian/Ubuntu).

Library usage

from qrcody import DEFAULT, build_svg, build_framed_svg

settings = {
    **DEFAULT,
    "text": "https://example.com",
    "pixels_style": "dots",
    "eyes_style": "circle",
    "frame": "scan-me",
    "frame_text": "Scan me",
}

qr_svg = build_svg(settings)
framed = build_framed_svg(qr_svg, settings)
svg_string = framed["svg"]  # framed["w"] / framed["h"] give the output dimensions

Layout check

validate_qr_layout(settings) inspects the same settings for problems that hurt scannability — an inadequate quiet zone, text that overflows the error-correction level, a center logo over a finder pattern or beyond error-correction capacity, frame text crowding the QR body — before you render:

from qrcody import validate_qr_layout

result = validate_qr_layout(settings)
if result["severity"] == "error":
    raise ValueError("; ".join(i["message"] for i in result["issues"]))

result["severity"] is "ok", "warn", or "error"; each issue is a dict with code, severity, and a human-readable message.

For PNG (requires the png extra):

from qrcody.png import svg_to_png

png_bytes = svg_to_png(svg_string, width=1000)

CLI

qrcody --url "https://example.com" --pixels squircle --frame perimeter -o qr.svg
qrcody --url "https://example.com" --pixels dots --eyes circle -o qr.png

Run qrcody --help for the full flag list — it mirrors the qrcody /api/qr HTTP API parameters (see the qrcody repo's functions/api/qr.js and the parameter table in its CLAUDE.md).

Settings dict

All keys from qrcody.DEFAULT (see defaults.py) are recognized; unspecified keys fall back to their default. Notable ones:

Development

uv sync --extra png
uv run pytest
uv run ruff check .

Known gaps vs. the JS implementation

• Logo embedding (logo / logo_scale settings) is supported in build_svg the same way as the JS version — pass a data URI as logo. There is no server-side "fetch a logo URL" helper here (that lives in the qrcody Cloudflare Worker's SSRF-hardened fetch, which is deployment-specific and out of scope for this package).
• No automated JS/Python golden-file parity test yet — the port was done by hand against src/lib/buildSVG.js and verified with a matching unit test suite, but the two aren't diffed against each other in CI. If the JS renderer changes, this package needs a manual re-sync.

Note on the package name

This package is published as qrcody on PyPI, distinct from the qrcody npm/web app it's ported from — there's no npm/PyPI namespace collision since they're different registries.