QR code is a two-dimensional barcode.

Displaying QR codes

• HDR QR Code
• The mathematics behind a 3D QR code explosion effect in ppqr.app (talk)

Scanning QR codes

• Adding a QR code scanner to a web app
• Reading data from OBZ Barcode Reader on the web using Web Serial API

Generating QR codes

• Google Charts provides a convenient URL to generate a QR code

  const qr = (payload) =>
    `https://chart.googleapis.com/chart?${new URLSearchParams({
      cht: 'qr',
      chs: '300x300',
      chl: payload,
    })}`

• In a command-line environment, use qrencode