Simon Hearne
simonhearne.com · Personal blog · on HN since 2019
Simon Hearne is a web performance specialist who writes on caching, web fonts, layout shifts, third-party scripts and certificates.
What HN saysHN links it for its article showing network can beat the browser cache, and for font-loading and layout shift advice. One commenter says a page scrolls poorly.
17HN people shared it
11linked it in comments
9stories submitted
552story points
2 years agolast shared
2019people per year2026
Most-shared posts
- 1When network is faster than browser cache (2020)7 people · 332 points · first shared 2020 · 111 comments on HN
- 2How to avoid layout shifts caused by web fonts3 people · 197 points · first shared 2021 · 121 comments on HN
- 3How to Find the Third-Parties on Your Site2 people · 2 points · first shared 2020 · discussion on HN
- 4Caching Header Best Practices1 people · 14 points · first shared 2022 · 3 comments on HN
- 5Measuring Performance behind consent popups1 people · 5 points · first shared 2020 · discussion on HN
- 6Six Web Performance Technologies to Watch in 20201 people · 1 points · first shared 2019 · discussion on HN
- 7Impact of Let's Encrypt Changes on Android Users (12% globally)1 people · 1 points · first shared 2020 · 1 comments on HN
- 8Drop ev certs1 people · first shared 2024
- 9Jank meter1 people · first shared 2025
What HN people wrote when they linked it
henning · 2025-03-07
The page does not scroll smoothly. https://simonhearne.com/2015/jank-meter/
dieulot · 2023-05-11
Yes, retrieval from disk caching is not as fast as one would expect. Detailed article: https://simonhearne.com/2020/network-faster-than-cache/
danielheath · 2023-01-15
https://bugzilla.mozilla.org/show_bug.cgi?id=1392841 is the bugzilla bug to enable the feature by default.
https://simonhearne.com/2020/network-faster-than-cache/ has some discussion.
smoe · 2022-08-25
There is some interesting things you can do with font-display and other css properties. E.g hide text for up to 100ms, if custom font has loaded swap to it, if not use fallback font.
https://simonhearne.com/2021/layout-shifts-webfonts/
ElectricalUnion · 2022-07-04
> I bet that the original 8 GB
Second source data I collected from the Steam Hardware Survey (that being a biased group with better that average specs) for 2012 seems to point that the "average Steam user" had around 5 GB of system RAM.
> HDD would be OK for browsing. Browsers got faster and that helps compensating sites that got slower.
I just remembered this article (and that article talks about SSDs, not HDDs!) surprising conclusions, posted in HN a few days ago: https://simonhearne.com/2020/network-faster-than-cache/
jesprenj · 2022-06-30
https://simonhearne.com/2020/network-faster-than-cache/#by-operating-s…
When I first saw this, I was confused why Linux (and Ubuntu and Debian) performed so poorly. But then I asked myself; is the data even representable? Or is Linux worse because users on Linux tend to stick to lower end hardware, since the measurenents were, AFAIR, taken for granted from website visitors instead of being tested on same hardware with different operating systems installed?
I don't know, can someone explain the discrepancy?
Is the raw data available? What is the number of requests that were included in the measurements for Debian (that doesn't hit cache in the first 5 ms)?
Thanks!
staticassertion · 2022-06-29
> Has anyone else observed this and have an explanation?
Yes that is the subject of this post.
https://simonhearne.com/2020/network-faster-than-cache/#the-obvious-bo…
cuu508 · 2022-01-30
> A standard web font (e.g. Roboto) is ~1MB.
Currently on HN frontpage there is an article "How to avoid layout shifts caused by web fonts" [1]. It lists several techniques you can use to reduce font size. One of the examples shows how subsetting reduces Roboto Regular size to 11KB.
[1] https://simonhearne.com/2021/layout-shifts-webfonts/.
jacobr · 2020-10-26
Even more food for thought - what if the cache is slower than the network? https://simonhearne.com/2020/network-faster-than-cache/
rbritton · 2020-01-23
Reference for what the different colors mean: https://simonhearne.com/2015/find-third-party-assets/