Drew Devault uses ani2html in builds.sr.ht, the continuous integration system/app that is part of the SourceHut suite. builds.sr.ht generates terminal output using jinja templates and a relatively small python library called ansi2html. It is already packaged by guix upstream as python-ansi2html (It could use an update).
Here are two examples of it in action at builds.sr.ht:
And, the relevant places in the builds.sr.ht code base:
Here's a diagram showing how it will integrate with binderlite.