Developers are divided by motivation. Some like to create websites, apps… — products for people. Others like to write code. They love a specific technology. The current wave of AI greatly supports the first group and threatens the second. Where do you belong?

7 tips for your #WebPerformance education: Every December, @stoyan.me publishes the excellent Web Performance Calendar. It is a great collection of insights from the world's top experts. Even in 2026, these articles are a "must-read." Here is what caught my eye this year (thread). ⤵️

Web performance is about conversions, not just metrics. ⚡ Google measures #CoreWebVitals on real users, not machines. If your site feels slow to them, your business pays the price. #CoreWebVitals #SiteSpeed #WebPerf #SEO

The fastest Czech website, according to the PageSpeed.ONE Awards, is built by Smarty Brands. 🏆 Results: pagespeed.cz/en/awards #WebPerformance #PageSpeed

The Inconvenient Truth: How Web Performance Case Studies Undermine Our Relationship With Business, by @machal.bsky.social: https://calendar.perfplanet.com/2025/the-inconvenient-truth-how-web-performance-case-studies-undermine-our-relationship-with-business/ #performance #metrics #economics

100ms ≠ 1%, do not trust the case study from Amazon Rather have a few high-quality case studies than many low-quality ones. It hurts the whole industry. My article for #WebPerf Calendar 2025. Thanks @stoyan.me! calendar.perfplanet.com/2025/the-inc...

AI is great, but… Today I asked ChatGPT to do a simple data analysis. A year ago, it handled it perfectly. Now? Errors, inconsistencies, crashes, lost prompts — twice it even crashed my browser tab with a memory leak. He’s a genius, but sometimes he drinks.

We can finally see in the data how hiring for junior roles has dropped since the arrival of #ChatGPT. The first chart shows demand for juniors. The second shows demand for seniors. The data is from the U.S. @economist.com What’s your experience?

#SaaS tools probably won’t die. But building your own data analysis interface inside them no longer makes sense. Just look at Toggl for example… Great app, but when it comes to working with data? Mostly inadequate. When #AI can deliver an analysis in seconds, it’s simply redundant.

Interesting: #AI vs. #ProductManagement 👇 AI generates ideas cheaply and quickly. But true reasoning is social: it emerges from debate and conflicting perspectives. Possible direction for AI? Systems that can actually disagree with each other and bring diverse views. lukew.com/ff/entry.asp...

Luke Wroblewski makes a good point: AI models aren’t stealing our content. They behave just like people — reading, watching, learning, synthesizing. lukew.com/ff/entry.asp...

Radiohead are touring Europe after 7 years. In Berlin alone, they’ll play 4 shows in a row. Tickets are sold in phases — each time you have to prove you’re not a scalper, and then it’s a lottery. Crazy. (And I didn’t get picked. 😭)

Why is it hard to predict the pace of #AI progress? Take airplanes, for example, their speed. From the Wright brothers’ plane to the first Boeing 7 series in the 1960s — half a century of huge progress. And then half a century of stagnation.

Writing text: – before AI: 1h – with AI: 15 min Meme search: – before AI: 15 min – with AI: 1h

#WebPerf audits from #SEO agencies…

We’ve just added case studies to our company's website. The results of our #WebPerformance work are pretty good. :) For example, we sped up sites like SIKO and Footshop by more than 2.5×. You’ll even find a few technical insights in there: pagespeed.cz/en/reference

This guy wants to work at 37signals — so he built a landing page and a pitch deck just for them. Brilliant. By the way, we hired our newest team member at out company thanks to a similar approach. Landing your dream job might be easier than you think. 37signals.kawaicheung.io

A real eye-opener for prioritizing #WebPerformance? Show your client their website on a low-end mobile device. infrequently.org/2024/01/perf...

What do you think the rise of AI — like AI Overviews in Google — means for the web? Extinction? Transformation? Opportunity?

Most people think optimizing #PageSpeed means: > “Let’s remove stuff. Delete as much as we can.” What it’s really about: > “Keep what you need. Just build it the right way.” This applies to everything: images, GTM, tracking tools, WordPress… As #WebPerf people we do #optimization, not #deletion.

My #WebExpo2025: AI, WebPerf & People — @tej.as – Web as food for AI, UI revolution — Tomáš Čupr – CEOs, AI, FOMO — @tammyeverts.com – Slow websites still hurt after users leave — @tkadlec.bsky.social – Core Web Vitals are just the start Thanks to Šárka and the @webexpo.bsky.social team!

Today marks 15 years since @ethanmarcotte.com introduced “responsive web design.” We decent web folks build for all devices now and don't think about it. But in a time when websites are fighting for relevance, it’s worth looking back at those 15 years. alistapart.com/article/resp...

You don’t say “I used a computer” to write something. So why say “I used AI”? It’s just a tool. Everyone’s using it.

I’ve got a team of assistants. While I’m writing an email to a client, images for an article are being generated, data analysis is running, and a newsletter summary is being prepared. #AI is turning all of us into managers. Success will belong to those who delegate and prioritize well.

They say 80% of programming will be done by #AI. …say those who’ve mostly never written a line of code.

We all use low-end devices way too little. 📱 I think that’s one of the big issues of #WebDevelopment. Today I browsed a few sites on an older mid-range Android, and it was a nightmare. 🙈

#WebPerformance: What hypotheses come to mind when you see a chart like this showing the geographic distribution of the INP metric? Graph is is for Central European E-commerce site. (I do have a strong hypothesis, but I’ll keep it to myself for now.)

OMG, how did I live without Dark Reader…! This is a Chrome extension for darkening sites without dark mode. Google Docs, Gmail, whatever… Everything is dark by default. My eyes love it at the night. ✨ darkreader.org

In the interfaces of #SaaS apps, small performance or UX annoyances often cumulate over time. Individually they’re not a big deal. The problem arises when they start to cumulate. The challenge? Users will never report this in their feedback. They just get a “weird feeling”.

I love this. Combined with #ChatGPT ability to generate #Markdown, “Paste into Markdown” is one of the best features of #GoogleDocs. Markdown, once a format for programmers, is now like middleware for content.

I read somewhere that wanting a quick end to this war means supporting the wrong side. Makes sense. 🇺🇦

Is B2B #SaaS in danger because of #AIagents? I’ve been thinking about this for a few months. I already have some thoughts on it… but first, I want to ask you: Is B2B SaaS in danger because of AI agents? And why? www.youtube.com/watch?v=uGOL...

New world order looks like this now? The U.S. under Trump now sees the world as bipolar: them versus China. Russia is a second-tier power, but it’s better for the U.S. to have it on their side than on China’s.

Double site conversions with instant page loads? Love this case study from Ray-Ban: +43% faster LCP +101% conversions on mobile But beware. ☝️ It’s not a free performance boost – but when done right, results can be amazing. 🔗 Case study: web.dev/case-studies... #SpeculationRules #PageSpeed

Trying to work with #Gemini AI in our company’s Workspace. The sidebar works great when working on Docs. It's not (yet) as good as #ChatGPT, but it's fast and has context. I keep saying that Google is underrated in the AI world, but in the end it may be one the winners.

We in the Czech Republic love these houses. Log cabins, we say "roubenky". OMG, I already miss it.

Of course it’s a coup. Miss the obvious, lose your republic. open.substack.com/pub/snyder/p...

The abilities of many capable people are ruined by the inability to master the art of saying “NO.” Are you competent? You’ll get more work. And so it goes, until you become an incapable person. Or until you start saying “NO”. That’s why “NO” is such an important word.

This week, we’re dropping the 2nd edition of our #WebPerf newsletter! 📬 Sign up now: www.speedjar.com #PageSpeed #CoreWebVitals #WebPerformance

We helped Shoptet, the leading Czech e-commerce platform powering 40,000+ e-shops, improve slower interaction responses (#INP) and enhance user experience. Thrilled to see the amazing impact of our #WebPerf work! 🎉 www.speedjar.com

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Our Czech (and Slovak) #frontend community, #Frontendisti, is celebrating its 11th anniversary! 🎉 They say the things we do for free often bring us the greatest joy – and this community is no exception. www.frontendisti.cz

Core Web Vitals are a mess and it's Google's fault. The most important thing is the data for the entire origin/domain. (But you need to know that you can find them in PageSpeed Insights, for example.)

Don’t Let Your Redesign Ruin Performance: A Case Study, by @machal.bsky.social (@[email protected]):

Web performance calendar day 26 with @machal.bsky.social suggesting we treat redesigns as performance-improvement opportunities calendar.perfplanet.com/2024/dont-le...

🚀 5 Key tips for optimizing INP in #React: - Reduce DOM size (<2,500 elements) - Split into simple/extended components - Leverage <Suspense> - Handle hydration errors - Be careful with useEffect() #ReactJS #WebPerformance calendar.perfplanet.com/2024/5-tips-...

My colleague Michal's article on #React #WebPerf optimisation tips: 1) Reduce the DOM size 2) Split components into two versions 3) Use <Suspense> 4) Beware of hydration errors 5) Watch out for useEffect() Code snippets included. ⤵️ calendar.perfplanet.com/2024/5-tips-...

What a fantastic #WebPerf Chrome extension by @toddhgardner.com! 👏 It shows the results of #CoreWebVitals in #SERP (1), the correlation of metrics with positions (2) and also the target values of metrics you need (3). chromewebstore.google.com/detail/keywo...

I can’t even remember the last time I read an article. Not because I’ve stopped learning—quite the opposite. #ChatGPT summarizes all the texts for me and puts them into the context of what I do. Then we discuss the topic further. What are your uses of #AI that you no longer even think about?

We are starting to experiment with a single score that reflects all #CoreWebVitals. Measuring #PageSpeed is complex and we are trying to bring it closer to people.