Tim Kadlec
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Posts, links, and the occasional book review.

  • May 18, 2026

    Losing Focus

    • ai
    • productivity
    • engineering
  • May 17, 2026

    2ality blog: temporarily offline

    Seeing a prominent voice in the web community for years go dark because of AI is depressing.

    Two things happened recently:

    The income from my book sales went from being enough for me to live off (2024) to zero (2026).

    The traffic to my blog and my books (which were free to read online) increased beyond what I can currently afford. Virtually all of it comes from AI crawlers, so there is no ad income.

    Finding a sustainable way of compensating authors for their work in this world where bots are scraping it all so aggressively for their own commercial gain is one of the most important problems to solve on the web.

    ∞ Permalink
  • December 2, 2024

    Web Performance Calendar » Goodhart’s law in action: 3 WebPerf examples

    Real world examples of how over-optimizing for metrics can be at odds with performance.

    Good cautionary reminder of Goodhart's law. This is why it's so important to choose your primary metrics with care, and to make sure everyone understands why.

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  • December 2, 2024

    A Layered Approach to Speculation Rules – Harry Roberts – Web Performance Consultant

    I love when standards, like Speculation Rules, are built in a way where there's a natural upgrade path. It's great for helping companies to gradually roll out support, but it also allows for some very smart optimizations, like what Harry does here pairing prefetch and prerender rules together.

    ∞ Permalink
  • October 21, 2024

    Why I’m skeptical of rewriting JavaScript tools in “faster” languages | Read the Tea Leaves

    Good food for thought here from Nolan Lawson about rewriting JS tools in "faster" languages.

    The point that a rewrite is often faster simply because it's a rewrite is a very valid one—over time we add more features/functionality to our code and it starts to have a cost not just on perf, but on maintainability as well. A rewrite lets us start with those learnings already in mind.

    But my favorite point is around the accessibility of JavaScript tools built in JavaScript:

    For years, we’ve had both library authors and library consumers in the JavaScript ecosystem largely using JavaScript. I think we take for granted what this enables.

    I wrote about this a few years back, but having JavaScript available on the front-end, back-end, on the edge, and in build tools is a powerful way to let developers extend their reach into different part of the tech stack and any decision to move away from that needs to be VERY carefully considered.

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  • October 21, 2024

    Paint Holding - reducing the flash of white on same-origin navigations

    Oldie but a goodie describing Chrome's "Paint Holding" optimization.

    ∞ Permalink
  • July 24, 2024

    What to Expect When You're Optimizing

    • performance
    • optimizations
    • process
  • July 26, 2023

    Introducing perfwork

    • hiring
    • product
    • jobs
  • June 30, 2023

    The Single Visionary Fairytale

    • user feedback
    • product
    • data
  • June 1, 2023

    Performance Is Not a Checklist

    • user experience
    • performance
    • web vitals
  • May 17, 2023

    Tracking Blocked Scripts - Chris Coyier

    So at first, it looked like about 10% of the BuySellAds scripts were being blocked. But after replacing how we were tracking the blocks with an internal service (just a little Redis counter), it was showing more like 28% of scripts being blocked.

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  • May 17, 2023

    Improving Performance with HTTP Streaming | by Victor | The Airbnb Tech Blog | May, 2023 | Medium

    Our experiments showed that Early Flush produced a flat reduction in First Contentful Paint (FCP) of around 100ms on every page tested, including the Airbnb homepage.

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  • May 11, 2023

    CSS Text balancing with text-wrap:balance - Ahmad Shadeed

    A bunch of examples of how text-wrap:balance could be useful.

    Could've used this just the other day, actually.

    ∞ Permalink
  • May 3, 2023

    Adactio: Journal—The intersectionality of web performance

    Jeremy discussing why performance isn't just about business, but actually has impact across several broad categories:

    • Business
    • Sustainability
    • Inclusivity

    Naturally, I agree.

    ∞ Permalink
  • April 23, 2023

    The Growing "Contentful" Gap

    • chrome
    • performance
    • web vitals
  • April 10, 2023

    The Performance Golden Rule Revisited

    • backend
    • frontend
    • user experience
  • April 5, 2023

    Returning to Performance Consulting

    • personal
    • consulting
    • performance
  • March 31, 2023

    Kill Your Darlings: The Ugly Other Half of Creativity

    Creativity happens in two stages: first, unbounded imagination; then — more importantly — ruthless editing.

    Loads of great advice in this post from Jason on the part of "ideas" that tends to get less attention: editing.

    One of the ones that jumped out to me was his note about the importance of underutilizing people's time:

    On top of that, a healthy team is intentionally underutilized. This creates free time for chasing shiny things with low risk. A roadmap with this kind of slack built-in supports exploratory tinkering by defining a clear plan with clear boundaries: I know I need to complete these 5 tasks this week to keep us on track; I finish them by lunchtime Thursday; I now have a day and a half to do whatever I find exciting without hurting the overall strategic goals or slowing things down.

    What a healthy (and wise!) counter from the way most organizations tend to operate.a

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  • March 31, 2023

    longtasks/loaf-explainer.md at main · w3c/longtasks · GitHub

    All of the above are part of the same issue - a task is an incomplete and inaccurate cadence to measure main-thread blocking.

    ∞ Permalink
  • March 22, 2023

    Health Benefits of Browser Diversity

    • safari
    • ios
    • browsers
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© 2026 Tim Kadlec.

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