QR code generator

GET /qr.png?url=<encoded HTTP(S) URL>
GET /qr.svg?url=<encoded HTTP(S) URL>
POST /qr.png or /qr.svg with JSON {"url":"..."}

Configured named codes: /<name>.png and /<name>.svg
Named redirects: /<name>

QR images have a four-module quiet zone and medium error correction.
No URLs are fetched or stored by the generator.