I recently discovered that the search engine DuckDuckGo generates a QR code for a query that begins with “qr” (it has been doing this since 2013).

DuckDuckGo QR demo

By the way, in addition to the plain text in the QR code can be written:

More information is collected here: https://github.com/zxing/zxing/wiki/Barcode-Contents

There are several QR code libraries for the Go programming language, and I used this one: https://github.com/liyue201/goqr

2020-04-22 Edit qr.md