When I am making a website, I do NOT use an online database, because APIs are hard to learn, and just writing to files is easier. So when I code a website, I write to files for a DB. Oh, and by the way, there isn't a single file for a DB, each key has a file, look at the tree below for an example.
database - --- key.txt --- other key.txt
Yea, I find that works really well for most use cases. Only if you want to store a really large amount of data does it make sense to use a proper database.