(Most of my projects had backends hosted on Heroku. Unfortunately, since Heroku doesn't support their free tier anymore, the websites below don't work)

"some of the biggest challenges faced by computers and human minds alike: how to manage finite space, finite time, limited attention, unknown unknowns, incomplete information, and an unforeseeable future; how to do so with grace and confidence; and how to do so in a community with others who are all simultaneously trying to do the same."  

-Brian Christian, Algorithms to live by