QRCGen API Documentation

Public API for generating ultra-lightweight SVG QR codes. Hosted on Cloudflare Workers with global edge caching.

Base URL: https://qr.qrcgen.com

Quick Start

https://qr.qrcgen.com/qr.svg?data=https://example.com

This returns a 302 redirect to a canonical, edge-cached SVG URL. The same input always produces the same URL — perfect for sharing and embedding.

Endpoints

`GET /qr.svg` — Share Link (redirect)

Best for sharing. Returns a 302 redirect to an immutable, edge-cached canonical URL.

Param	Required	Default	Description
`data`	yes	—	URL or text to encode (max 4,096 chars)
`p`	no	`sq250`	Size preset: `sq125`, `sq200`, `sq250`, `sq300`
`ecc`	no	`M`	Error correction: `L`, `M`, `Q`, `H`
`q`	no	`4`	Quiet zone in modules (0–16)

Example:

https://qr.qrcgen.com/qr.svg?data=https://example.com&p=sq300&ecc=H
  → 302 → /qr/sq300/a1b2c3...f0.svg

The canonical URL is deterministic: same parameters always produce the same hash. Once cached, responses are served instantly from the nearest Cloudflare edge location.

`GET /qr.inline` — Direct SVG (for embedding)

Returns SVG directly as a 200 response. No redirect. Ideal for <img> tags, Markdown, or anywhere you need the image immediately.

Same parameters as /qr.svg.

Example:

<img src="https://qr.qrcgen.com/qr.inline?data=https://example.com" alt="QR code" />

Edge-cached by full URL (24h TTL). X-QR-Cache: HIT|MISS header for diagnostics.

`GET /qr/<preset>/<hash>.svg` — Canonical URL

This is where share links resolve to. You don’t call this directly — use /qr.svg to get the redirect.

Response headers:

Content-Type: image/svg+xml; charset=utf-8
Cache-Control: public, max-age=31536000, immutable
ETag: "<hash>"
X-QR-Cache: HIT|MISS

Size Presets

Preset	Dimensions	Use case
`sq125`	125 × 125 px	Inline icons, small badges
`sq200`	200 × 200 px	Cards, compact layouts
`sq250`	250 × 250 px	Default — good for most uses
`sq300`	300 × 300 px	Print, hero sections

All presets produce square SVGs. The SVG viewBox uses module units; width and height are in pixels from the preset.

Error Correction Levels

Level	Recovery	Best for
`L`	~7%	Clean digital display, maximum data density
`M`	~15%	Default — balanced for screen and print
`Q`	~25%	Printed materials that may get worn
`H`	~30%	Harsh environments, small print sizes

Higher ECC means more redundancy, which makes the QR code denser (more modules) but more resilient to damage.

SVG Output

Every QR code is a single-line, optimized SVG:

~5 KB typical size (vs 80+ KB from other generators)
One <rect> (white background) + one <path> (black modules)
Horizontal run-length encoding: M{x} {y}h{w}v1h-{w}z
Integer coordinates only — no floating point
shape-rendering="crispEdges" for pixel-perfect display
No mask, clipPath, <g>, or unnecessary elements

Embed Snippets

HTML

<img src="https://qr.qrcgen.com/qr.inline?data=YOUR_URL" alt="QR code" />

HTML (object)

<object data="https://qr.qrcgen.com/qr.inline?data=YOUR_URL"
        type="image/svg+xml" aria-label="QR code"></object>

Markdown

![QR](https://qr.qrcgen.com/qr.inline?data=YOUR_URL)

React

export function QR() {
  return <img src="https://qr.qrcgen.com/qr.inline?data=YOUR_URL"
              alt="QR code" loading="lazy" />;
}

Vue

<template>
  <img :src="src" alt="QR code" loading="lazy" />
</template>
<script setup>
const src = "https://qr.qrcgen.com/qr.inline?data=YOUR_URL";
</script>

Caching

Canonical URLs (/qr/<preset>/<hash>.svg): cached for 1 year (immutable). Same hash = same content forever.
Inline URLs (/qr.inline?...): cached for 24 hours by full URL.
Redirect URLs (/qr.svg?...): not cached — always computes the redirect.

The QRCGen extension warms the cache automatically when you generate a QR code, so share links load instantly for recipients.

Rate Limits

No authentication required. No API keys. Generous limits for normal use.

Privacy

No accounts, no cookies, no tracking
No analytics on API requests
QR data is used only to generate the image and compute the cache key
The SHA-256 hash in canonical URLs is one-way — the original data cannot be recovered from the URL

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