Echo JS 0.11.0

Two books that still hold a lot of value are "High Performance Websites" and "Even Faster Websites" both by Steven Souders who works(ed) on web performance at Google.

There are a lot of tidbits like this that can add up a lot.

Personally, I tend to deploy/configure most of the applications that I work on such that all requests are to a single origin that may reverse-proxy to differing systems/applications on the backend.  For example, I almost always separate static resources, /api and /auth from each other.

That method of prefetching images took me back 20 years...