🚀 Independent Web Performance Consultant • Speaker • Google Developer Expert, Web Performance • Accepting new clients • https://harry.is/for-hire
and yes!

@csswizardry.com
🚀 Independent Web Performance Consultant • Speaker • Google Developer Expert, Web Performance • Accepting new clients • https://harry.is/for-hire
and yes!
Yes
Everything else aside, it’s poor branding. We never called Sass ‘CSS-in-Ruby’ for good reason.
One of the healthiest things a developer can do when faced with a bug or regression is doubt themselves first, but sometimes it’s something completely out of your hands.
Two of my favourite opening slides from my ongoing work with LEGO. Sometimes, site-speed really is a *them* problem. It’s a function of your work and your audience, and one, both, or neither can move the needle.
Your site seems very broken. For me, there is no content on either your home or contact pages and your social links just point to the platforms’ homepages.
It’s a real shame that folk a decade ago weren’t warning developers against utterly insane things like CSS-in-J — oh.
🇬🇧 ✈️ 🇳🇱
Just landed in Schiphol ready for @fronteers.bsky.social Dark Mode tomorrow!
#WebPerfWednesday 11 is out, in which we fix a longstanding bug in @speedcurve.com, and Safari gets network throttling! csswizardry.com/2026/09/web-...
Tomorrow, I’m starting a new project with LEGO. Look how excited I am!
What is Time to First Byte and what can you do about it? csswizardry.com/2019/08/time...
Stunning event!
Are you getting the most out of your Speculation Rules? Probably not! csswizardry.com/2024/12/a-la...
If you’re tracking your Core Web Vitals with synthetic, you probably also want to track your Total Blocking Time window: csswizardry.com/2026/06/fron...
The reason this has been absent for so long is that @csswizardry.com is built on Jekyll which has no first class support for categories and tags, so I’m especially proud of this: csswizardry.com/blog/tags/
Over the last day or so, Codex and I have been working on adding a proper taxonomy and associated categories and tags to the blog. Finally, @csswizardry.com has a proper archive! csswizardry.com/blog/
Another day, another compelling use case for `No-Vary-Search`! csswizardry.com/2026/05/bett...
I have ChatGPT read my `.vimrc` and send me a daily #Vim tip to read with my morning coffee.
I’ve always had a very good habit of `[TAGGING]` things like calendar events or Jira titles and the like — it makes it so much easier to find arbitrary topics with simple grep or search. It turns out it’s *incredibly* useful in this agentic world!
That’s the key feature for me for definite. It’s an almost-hands free process!