Not sure why this even needs a backend though, as the post above you mentions, this could be made all in the frontend. Doesn't seem like very complicated math.
However, then again $0.21 is not very much but, when it could be free...
However, then again $0.21 is not very much but, when it could be free...
I guess you could rope some CI service with a free tier into service instead, updating a file on GitHub, but...
I've been thinking about using such public git providers to store small amounts of data, possibly encrypted. For example important documents that I don't want to lose. It seems that it'd be ok as long as you manually create the account.
There was a post here a while ago (that I cannot find anymore) about the devs of a package manager of sorts who were asked kindly by Github to do something about their excessive data usage. So it's probably not a good idea to build a company on it.