[taylodl]

> Site performance is much more API based

Exactly. And those API calls are going out over the network. The caller has to serialize the request into text, the API implementation has to deserialize the text into values that can be passed to a local implementation function and then the API implementation has to take the result and serialize it into the return. Finally the caller has to process the result.

That's the simple case. Things get even more involved when you start using HTTPS to secure the data in transit on the channel and using OAuth to secure the access to the API. What appears to be a simple API call turns into a lot of back-and-forths with multiple servers - with all the network latency that entails. Then developers complain their website is slow. Gee, I wonder why!