We actually ran off of WeasyPrint at first but switched to Chromium due to emojis not rendering properly, poor flexbox support, no custom fonts, and other differences between the HTML you'd see in a browser vs. the generated PDF.

WeasyPrint implements its own rendering engine and might support some specific @page properties that Chromium does not but given the complexity of CSS and web browsers, you're generally better off sticking with Chromium due to its history.

Also – an added benefit is that we can use JS libraries like FontAwesome, Bootstrap, KaTeX, etc. which is where other HTML to PDF libraries fall flat.