Do you need the link forwarding and analytics, or do you just want to generate QR codes?

There are several NPM packages (and I'm sure equivalent for whatever language you use) for generating QR codes, for instance: https://www.npmjs.com/package/qrcode

There's a ton of great examples here: https://github.com/738/awesome-url-shortener

We're also working on the open-source link management platform at https://dub.co – feel free to give it a try!

What feature(s) do you need?

A) Link shortener (with ability to change the destination)?

B) Customizable look/color/logo for each QR code?

C) Analytics?

If you only need (A), then any link shortener will do. Given a URL, generating a QR code is trivial.