It's fast. It's static. CDN as mentioned. Nothing impressive here though. This wheel has been done.

Lighthouse gives it a 99 and the footer says that the site is “100% JavaScript free”. Did you mean runtime performance?

It's not slow by any stretch of the word compared to the rest of the web.

A clean reload transfers only 300kb of data that uncompresses to 670kb. Of that 223kb(570kb uncompressed) are fonts which are heavily cached and change rarely if ever. DOMContentLoaded fires after 80ms.

Subsequent loads are completely cached.

In an age where the average website is multi megabyte https://swiftbysundell.com/ is a refreshing and excellent demonstration of how good the web can be.

The site is being served directly by CloudFlare's CDN, hard to make it much faster than that.

It seems slow because the content isn't loaded yet. The first visit is faster, each subsequent click takes longer.

That is good for blogs, news and similar because you rarely go through several pages, but horrible for webapps where you spend a lot of time switching between content

It's very fast for me. (~200ms from request start to first contentful paint)

Actually it’s quite fast for me compared to “modern” sites.

How did you measure its performance?