I recently participated in an online Prolog class by Anne Ogborn. It utilized SWI-Prolog [2] and SWISH [3], and mentioned Pengines [4] for web. I haven't used it personally, but that is the pointer I have for Prolog + web.

[1] https://twitter.com/AnnieTheObscure [2] https://www.swi-prolog.org/ [3] https://swish.swi-prolog.org/ [4] https://pengines.swi-prolog.org/docs/index.html [5] http://pathwayslms.com/swipltuts/ [6] https://www.youtube.com/watch?v=JmOHV5IlPyU