I created a bespoke comments system for a blog section of an e-commerce website (TOAST). The comments were written and read from Google Firebase. The comments had a level of nesting where we allowed one tier of 'replies' to comments, meaning we had to assign child comments a parent ID to allow it to display correctly.

Firebase was the correct choice as it was very quick and it's NoSQL nature suited our requirements.

https://www.toa.st/blogs/magazine/supporting-local-farming-at-british-wool