New blog post about an experiment in measuring how rendering times are affected by the size of SVGs www.phpied.com/measuring-sv...

New blog post www.phpied.com/oops-i-build...

I don't think there are many music dictation apps out there, but here's v1 of mine. Rhythm-only for now, part of the sightread.org project. To try sightread.org?rhythm-dicta... To read the blog post sightread.org/blog/quests-...

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). ⤵️

look ma' I'm now opining about AI like the big kids www.wearedevelopers.com/en/videos/17...

New blog post www.phpied.com/type-checkin... This is now part 4 of something I thought will be a quick note. Installment 4 talks about type checking without TypeScript. Hello JSDoc! And so the DIY-ing continues until morale improves!

Huge congrats and kudos to @stoyan.me for running it and to all the authors for writing articles for this year's Web Performance calendar. calendar.perfplanet.com/2025/ The quality was very high, and it feels like every second post was a banger!

New blog post: www.phpied.com/maximally-mi... It's about staying away from most everything the JS ecosystem has to offer and stick close to the web platform. A build is still necessary because of long lived caches and updates but it can be tiny and simple. Time will tell how this strategy plays out

Let's make 2026 the year to make web simple again. Not everything needs to be an app, sometimes its just idk a website. 🥳🥳

People like to say “once the single page app is booted, it’s faster”, but they’re wrong — stats show few subsequent navigations occur. React simply isn’t worth the cost for most websites.

I almost slipped this article because that headline is usually a red flag to me. But I'll be damned, every single one of these features slap.

Put the NYE champagne down… my article is up on the 2025 Web Performance Calendar 🥳

@stoyan.me it's been a fantastic Web Performance Calendar, thank you for curating it and Happy New Year!

Wrapping up the year with my article for the Perf Calendar with my write up about how I ended up creating agent.perflab.io! It has AI, it has Perf…what else could you want 😎🔥 I’m always happy to see my content in the Performance Calendar! Thanks for the initiative @stoyan.me !

Web Performance Calendar day 31 article 5/5: @infrequently.org investigates SPA usage patterns showing that users often trigger only ~1 soft navigation per page load. If the heavy upfront JS costs aren’t being amortized, what are SPA's performance benefits? calendar.perfplanet.com/2025/the-cur...

Web Performance Calendar day 31 article 4/5: @twnsnd.com on Compression Dictionaries to dramatically shrink responses (60–90% smaller than Brotli/GZIP). Why adoption is slow. Practical architectural decisions and implementation tips to get huge bandwidth wins. calendar.perfplanet.com/2025/from-th...

Web Performance Calendar day 31 article 3/5: Can AI meaningfully help with real-world performance analysis? @webx.bsky.social explores how to train AI/LLM agents to interpret complex browser data (like DevTools traces) into actionable insights. calendar.perfplanet.com/2025/teachin...

Web Performance Calendar day 31 article 2/5: @keerthanak17.bsky.social on making friends with Chrome DevTools and transforming it into a powerful tool for deep understanding, debugging, and improving of real-world web performance calendar.perfplanet.com/2025/chrome-...

Web Performance Calendar day 31 article 1/5: Tsvetan Stoychev shares that BasicRUM (open-source Real User Monitoring tool) will have its source code released Q1 2026. Self-hosted, privacy-friendly, with AI-powered insights & dashboards to spot perf issues calendar.perfplanet.com/2025/open-so...

New blog post about subsetting a ligature-heavy font highperformancewebfonts.com/read/subsett... Almost always we subset based on text. But in my case, a more fine-tuned glyph-based approach saves 91% of bytes as opposed to 74% in the usual way. Worth it?

Our Web Performance Journey guide is live on PerfPlanet Calendar!

Web Performance Calendar day 30 with @sergeyche.dev, Eric Goldstein and Alex Chernyshev on mastering perf: get business to care, link UX speed to outcomes, set thresholds, understand real users with percentiles, trends, distributions, tie to business metrics calendar.perfplanet.com/2025/7-steps...

I added a little feature to sightread.org to remove the chrome so I can screen-record exercises UI-free and post them as Instagram reels. This way folks can squeeze a bit of practice while scrolling. If that sounds like you: www.instagram.com/sightreadorg/

My contribution to this years Web Performance Calendar is all about Third Parties and Single Points of Failure (SPOF). Based on @httparchive.org data I found that 67% of websites have at least 1 render blocking third party - and quite a few of them are SPOF risks!

Web Performance Calendar day 29 with @paulcalvano.bsky.social's research on 3rd parties, SPOF, and the need to test and monitor these. 67% of sites out there have at least 1 render-blocking external dependency. calendar.perfplanet.com/2025/third-p...

My article for Performance Calendar is live, looking at tips to help focus when doing performance traces.

Web Performance Calendar day 28 when Ian Duffy shows us how to tame Chrome’s Performance panel: reduce noise, search fast, annotate, use Insights, and customize tracks calendar.perfplanet.com/2025/tips-fo...

Web Performance Calendar day 27 with @nucliweb.net on using Chrome DevTools for fun and profit: inspect heavy files in Network panel, monitor Core Web Vitals, record performance traces, validate optimizations, and more. calendar.perfplanet.com/2025/chrome-...

Web Performance Calendar day 26 with Sébastien Mischler on HTML streaming/flushing and how this old trick (featured in the first edition of the calendar) applies to today's CSR world. Show content now, not after JS finishes thinking. Fast pages, happy users. calendar.perfplanet.com/2025/revisit...

Web Performance Calendar X-mas edition with Nicolas Hodin on BFCache: a huge UX win, but easy to break with Cache: no-store, unload handlers, iframes, or long-lived connections calendar.perfplanet.com/2025/chasing...

New blog post "Lazy-Loading Optional Fonts with Native Browser API" describing a wee trick I do on sightread.org to load music glyphs, optionally highperformancewebfonts.com/read/lazy-lo...

I’m using No-Vary-Search in production already—you probably should be too! @tunetheweb.com has the details 👇🏻

This one got released rather quietly and I think could do with a bit more attention! Read about how to avoid caching performance penalties due to tracking query params and the like!

Web Performance Calendar day 24 with @programmingart.bsky.social on TTFB. Yes, it's one of those X-mas Eves where we cuddle by the fire, drop everything and immerse into re-learning and re-evaluating what we thought we knew about a concept we use daily calendar.perfplanet.com/2025/ttfb-do...

Web Performance Calendar day 23 with @tunetheweb.com on configuring caches to ignore non-content-affecting URL parameters and reclaim performance. No more of this query string = cache miss nonsense. calendar.perfplanet.com/2025/fixing-...

Web Performance Calendar day 21 with Conor McCarthy and lessons learned from web perf client site reviews calendar.perfplanet.com/2025/insight...

Web Performance Calendar day 20 with @verlok.bsky.social on CLS-friendly skeletons. Can you "load more" while keeping layout shifts to a minimum? calendar.perfplanet.com/2025/optimiz...

Web Performance Calendar day 19 with Alex Podelko on how performance engineering has evolved with computing: from mainframes to distributed systems, web/mobile, cloud, AI. Knowing your history may help reduce wheel-reinvention and encourage skills reuse calendar.perfplanet.com/2025/a-short...

Web Performance Calendar day 18 with Amrik Malhans on breaking down LCP to pinpoint what's slowing down the page exactly and where to focus your UX-optimizing efforts calendar.perfplanet.com/2025/the-ana...

Web Performance Calendar day 17 with Adam Zachary Wasserman on outperforming modern frameworks with this one weird little trick calendar.perfplanet.com/2025/the-old...

Web Performance Calendar day 16 with @sandervs.bsky.social on why the word "millisecond" doesn't belong in the boardroom calendar.perfplanet.com/2025/why-we-...

Web Performance Calendar day 15 with @nicj.net, @cliffcrocker.bsky.social and @karlijnlowik.bsky.social Löwik presenting an update on W3's RUM Community Group and YOU calendar.perfplanet.com/2025/rumcg-a...

Web Performance Calendar day 14 with Morgan Murrah on compositing for smooth web animations and how GPU-friendly properties (transform, opacity) keep animations off the main thread calendar.perfplanet.com/2025/a-tale-...

Web Performance Calendar day 13 with Yoav Weiss (@yoav.ws) showing us a clever and creative way to ship *only* critical/necessary CSS for each page type (home, search, etc) while also avoiding duplicate code in the CSS bundles. calendar.perfplanet.com/2025/how-to-...

Web Performance Calendar day 12 with @adevnadia.bsky.social's investigation of React Server Components, their pros and cons compared to client-side rendering and traditional server-side rendering (with/without data fetching with/without Next.js) calendar.perfplanet.com/2025/intro-t...

Web Performance calendar day 10 with yours truly using ML and HTTPArchive data to explore an "AI webperf consultant" idea. YSlow (pronounced “Why Slow?”) meets aiSlow (pronounced “Eh, I Slow?”). calendar.perfplanet.com/2025/aislow/

Web performance folks, the pipeline of the advent calendar is dry. If you were thinking of writing or you've started, now would be perfect time to wrap it up and send it over. Thanks a million to everyone who'd helping! If you don't know what I'm on about, see calendar.perfplanet.com/contribute

Web Performance day 10 with Michal Matuška on what's new in React perf: <Activity> for stateful hidden UI and the Performance Tracks in DevTools for full-timeline visibility of what React is doing calendar.perfplanet.com/2025/react-1...

Hello London!

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...