QR Code API (Node.js)

Simple micro app that returns a QR code image from an API call.

Setup

npm install

Run

npm run dev
# or
npm start

Default URL: http://localhost:3000

Endpoints

• GET /health
• GET /api/qr?text=Hello%20World
• POST /api/qr with JSON body

GET example

curl "http://localhost:3000/api/qr?text=Hello%20World&size=400" --output qr.png

POST example

curl -X POST "http://localhost:3000/api/qr" \
  -H "Content-Type: application/json" \
  -d '{"text":"https://crewsportswear.app","size":500,"margin":2}' \
  --output qr.png

Optional parameters

• size (number, default 512, min 128, max 2048)
• margin (number, default 2, min 0, max 10)
• dark (hex color, default #000000)
• light (hex color, default #FFFFFF)

Docker

Local Docker run

docker compose -f docker-compose.local.yml up -d --build

Local URL: http://localhost:3000

Production (Traefik)

docker compose -f docker-compose.prod.yml up -d --build

Traefik host rule: qr.crewsportswear.app

Notes:

• Uses external Docker networks: traefik-public and crew-app-net
• Internal service port is 3000
• TLS uses Traefik Let's Encrypt via tls.certresolver=le
• Includes HTTP -> HTTPS redirect via Traefik labels

Restrict QR generation by IP

The /api/qr endpoints support IP allowlisting via environment variable.

• ALLOWED_QR_IPS: comma-separated list of allowed client IPs
• TRUST_PROXY: keep this true behind Traefik so client IP is read from forwarded headers

Example .env values for production:

ALLOWED_QR_IPS=203.0.113.10,198.51.100.22
TRUST_PROXY=true

If ALLOWED_QR_IPS is empty, IP filtering is disabled.