If you like things like Janet, you might also like s7 Scheme. It is also a minimal Scheme built entirely in C and dead easy to embed. I used it to make Scheme for Max and Scheme for Pd, extensions to the Max and Pd computer music platform to allow scripting them in Scheme. (https://github.com/iainctduncan/scheme-for-max) Janet was one of the options I looked pretty closely at before choosing s7.

The author (Bill Schottstaedt, Stanford CCRMA) is not too interested in making pretty web pages, ha, but the language is great! https://ccrma.stanford.edu/software/snd/snd/s7.html