Yep. I understand this is just a little toy thing, but people are really trying to start businesses off of "APIs" that do not much more than OP's.

The whole point of an API is that you defer a significant amount of serverside processing and logic to a remote host, and receive a nicely formatted and machine-readable response. You have to deal with the overhead of a TCP connection (handshaking / RTT), an HTTP request, and an HTTP response. If you're doing that every time a user visits your web page (or app view or whatever), especially multiple times, then you better have a good reason for doing so.