rqrcode is a library for encoding QR Codes. The simple interface allows you to create QR Code data structures and then render them in the way you choose.

Health Cards implements SMART Health Cards, a secure and decentralized framework that allows people to prove their vaccination status or medical test results. It is based off of W3C Verifiable Credentials and FHIR R4 health data exchange standards. It allows conversion of clinical data into JWS which may then be embedded into QR codes, exported to smart-health-card files, or returned by a $health-card-issue FHIR operation.

QR PNG Generator for Ruby. Leveraging RQRCode and MojoMagick modules

Additional functionality for HexaPDF

A gem to generate working QRCodes with images in their background