For example, the following URL results in the QR Code for https://brentlogan.com/.
Note, the above list URL is shown on two lines for space reasons only. It should be one continuous URL with no spaces.
<img> form to embed the resulting QR Code in a web page does not (yet?) work. I guess that’s to be expected when using an undocumented feature of the API.
Update: The following now works:
<img src="https://chart.googleapis.com/chart?chs=100x100&cht=qr&chl=https://brentlogan.com/" />
resulting in the image below: