iiinova — where your digital self keeps evolving

Reposted by Robin Marx

Henri Helvetica 🧑🏾‍🚀🇭🇹 @henrihelvetica.bsky.social · 13/05/2026

📢 Tomorrow will be H2 protocol's anniversary. With multiplexing, updated header compression and more, H/2 was a timely arrival. To discuss the arrival of H2, we are joined by none other than @programmingart.bsky.social expet in web protocols! 📆 May 14TH ⏰ 2PM EDT 🔗 www.youtube.com/live/ZD9vTom...

SPDY streams Presents. HTTP2 anniversary AMA. Thursday, May 14, 2 PM Eastern daylight time, 8 PM central European standard time.

051

Reposted by Robin Marx

PerformanceObserver @performanceobserver.dev · 13/01/2026

Happy New Year, folks! The next PerformanceObserver will be in a few weeks on Jan 28 featuring Morgan Murrah and Robin Marx (@programmingart.bsky.social) ! Join us live for access to chat and Q&A - all details and add to calendar at: performanceobserver.dev #webperf

performanceobserver.dev

PerformanceObserver: A virtual web perf meetup

Join the PerformanceObserver virtual performance meetup to get all the latest web performance news and hang out with the community.

052

Robin Marx @programmingart.bsky.social · 06/01/2026

TTFB is a notoriously difficult performance metric, because it has so many different definitions and nuances. New features like Early Hints and Speculation Rules only make that worse. My new blog highlights these issues so you know what to keep in mind: calendar.perfplanet.com/2025/ttfb-do...

calendar.perfplanet.com

TTFB doesn't mean what you think it means

Time-To-First-Byte (TTFB) is a popular performance metric, yet there are many problems and nuances with it. Not only does it have several different definitions, it is usually also a "compound" metric,...

021

Reposted by Robin Marx

Stoyan Stefanov @stoyan.me · 24/12/2025

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...

calendar.perfplanet.com

TTFB doesn't mean what you think it means

0113

Reposted by Robin Marx

Karlijn Löwik @karlijnlowik.bsky.social · 31/10/2025

Halloween at #perfnow, pirates and vampires. A.k.a sword fight, the sequel. Or... How RUMvision slayed Akamai😇😆 (jk)

2143

Reposted by Robin Marx

Keerthana Krishnan @keerthanak17.bsky.social · 31/10/2025

@programmingart.bsky.social and I are on the same page for a lot of things but I'm still learning from the master on how much drip a Halloween costume should have #perfNow

0152

Reposted by Robin Marx

EricLaw 🎻 @ericlawrence.com · 30/09/2025

It’s not the whole story, but if you cannot see the truth of this, you need to pay more attention.

0102

Reposted by Robin Marx

Henri Helvetica 🧑🏾‍🚀🇭🇹 @henrihelvetica.bsky.social · 16/03/2025

Day 011 #100DaysOfPerf: I shared the hpbn book (Day 002) that wall about levelling up on HTTP. Well, let's look at CURRENT HTTP data from the @httparchive.org's Web Almanac. On deck ✨ HTTP ✨ by none other than @programmingart.bsky.social. Let's take a look: 🧵⬇️ almanac.httparchive.org/en/2024/http

illustration of 3 cars driving down a 3 lane road, carrying web resources

1103

Reposted by Robin Marx

WebPerformance Report @webperfreport.bsky.social · 23/02/2025

Featured posts this week: ⚡ Fast and furious: @catchpointsystems.bsky.social ⚡ How browsers REALLY load Web pages: @programmingart.bsky.social ⚡ Client-Side Rendering: @adevnadia.bsky.social ⚡ More Edge features get a perf boost: Mohamed Mansour Special thanks to the authors.🙏

031

Robin Marx @programmingart.bsky.social · 18/02/2025

The "contributing" options on the web.dev bottom for example don't seem quite as inviting as say github.com/mdn/content, which imo helps reinforce the impression this is a google/chromium-first thing. (just trying to provide some feedback on why I had my initial impressions on web.dev)

github.com

GitHub - mdn/content: The content behind MDN Web Docs

The content behind MDN Web Docs. Contribute to mdn/content development by creating an account on GitHub.

110

Robin Marx @programmingart.bsky.social · 18/02/2025

Arguably, you can't expect Chrome engineers to add non-chromium behaviours in there, but it's also unclear (at least to me on the outside looking in) if you would accept contributions from say Firefox/Safari/outsiders to extend that type of article with cross-browser content (it's already extensive)

100

Robin Marx @programmingart.bsky.social · 18/02/2025

Good to know this is the intent (as @paul.kinlan.me also echoed), but from my perspective, web.dev articles that talk about the type of topics I research, are usually still exceptionally chromium-focused, even for features in baseline (prime example being web.dev/articles/fet...).

web.dev

Optimize resource loading with the Fetch Priority API | Articles | web.dev

The Fetch Priority API indicates the relative priority of resources to the browser. It can enable optimal loading and improve Core Web Vitals.

100

Robin Marx @programmingart.bsky.social · 18/02/2025

Thanks Patrick. I would definitely be interested in contributing docs, I'm just not sure where they would fit best. Web.dev is traditionally google/chromium-focused and not sure if they'd want to change. MDN doesn't seem to do much of this more "fuzzy" content in my experience, but maybe I'm wrong?

web.dev

Guidance to build modern web experiences that work in every browser.

310

Robin Marx @programmingart.bsky.social · 01/02/2025

Sadly yes... Dinner date with the wife I'm afraid

210

Reposted by Robin Marx

Firefox Performance @firefoxperformance.bsky.social · 01/02/2025

We kick off with @programmingart.bsky.social showing us how browsers REALLY load web pages to a full room! 🤡 fosdem.org/2025/schedul...

2195

Reposted by Robin Marx

Henri Helvetica 🧑🏾‍🚀🇭🇹 @henrihelvetica.bsky.social · 13/01/2025

HTTP/1.1/2/3 are all present in unison on the web today, w/ a 21/70/9 split. Or is it? @programmingart.bsky.social will shed the light on the @httparchive.org Web Almanac data, and the reality of the protocol's adoption. Join us to hear him share findings this Thursday 🔗 ⬇️ bsky.app/profile/henr...

Http version usage per website
on desktop: 22%, H1, 71% H2, 7%, H3
on Mobile: 21%, H1, 70% H2, 9%, H3

092

Reposted by Robin Marx

Patrick Meenan @patmeenan.com · 06/01/2025

Hmm, interesting - looks like Chrome added support for the ORIGIN frame for HTTP/3 (eliminating the need for a DNS lookup before coalescing connections). blog.chromium.org/2024/12/maki...

blog.chromium.org

Making Chrome QUICer

In October 2020, Chrome enabled HTTP/3 by default . HTTP/3 ( RFC 9114 ) runs over IETF QUIC ( RFC9000 ). Default-enabling HTTP/3 in Chrome ...

1217

Reposted by Robin Marx

Stoyan Stefanov @stoyan.me · 30/12/2024

Web performance calendar day 29 with @patmeenan.com on how to ship a production-quality dictionary compression implementation to reduce HTML/JS/CSS response sizes dramatically (as in 60-90% dramatically!) calendar.perfplanet.com/2024/getting...

calendar.perfplanet.com

Getting Real (small) With Compression Dictionaries

Compression dictionary transport is a relatively new feature in HTTP that allows for using custom compression dictionaries to improve the compression of HTTP responses. The results can be pretty drama...

02914

Reposted by Robin Marx

Stoyan Stefanov @stoyan.me · 21/12/2024

Web performance calendar day 21 with @timvereecke.bsky.social giving us the gift of UNO (Unattributed Navigation Overhead) - an insight into the blind spot gaps between TTFB components calendar.perfplanet.com/2024/uno/

calendar.perfplanet.com

Unattributed Navigation Overhead (UNO)

I promise you, UNO (Unattributed Navigation Overhead) is the best Christmas present you will get this year! UNO, not the card game, is the missing piece for many of your unsolved performance puzzles...

1118

Robin Marx @programmingart.bsky.social · 18/12/2024

Let's hope we can re-invigorate that then :) Thanks for sharing!

020

Robin Marx @programmingart.bsky.social · 16/12/2024

For this year's #webperf calendar, I wrote "Top 8️⃣ things I want in the Devtools Network Panel". I often struggle to debug modern networking features in browsers (like DNS HTTPS records, 0-RTT, and Happy Eyeballs 👀) and have some ideas on how to improve that! calendar.perfplanet.com/2024/top-8-t...

calendar.perfplanet.com

Top 8 things I want in the Devtools Network Panel

Look, I'm just going to come out and say it: I'm a jealous man. I'm not proud of it, but I'm a jealous man. These past months and years, I've seen great update after amazing update (not you) being rel...

231

Robin Marx @programmingart.bsky.social · 11/12/2024

Hmz that's indeed much lower than I would have expected... Maybe @tunetheweb.com can have a look once he's less busy? 😇

100

Robin Marx @programmingart.bsky.social · 11/12/2024

But as a percentage of all sites that use preload (the ~2.5 million): 235,535 / 2,506,138 = 0.09 = 9% 228,895 / 2,506,138 = 0.09 = 9% so about 18% combined (round up to say 20% for the leftovers that uselessly preload more than 2 resources). Hope that helps :)

110

Robin Marx @programmingart.bsky.social · 11/12/2024

Hm, I think it's more like 20% :) Looking at the raw results (docs.google.com/spreadsheets...). 2,506,138 used preload (~20 of all desktop homepages) 235,535 has 1 unused preload (~1.9% of all desktop homepages) 228,895 has 2 unused preloads (~1.85% of all) Combined <4% of total (as reported)

110

Robin Marx @programmingart.bsky.social · 10/12/2024

My meme-game is on-point for my (first) perfcalendar 2024 submission @stoyan.org!

021

Robin Marx @programmingart.bsky.social · 10/12/2024

MASSIVE thank you to @tunetheweb.com, without whom there would have been no data to write about in the first place! Barry is consistently one of the kindest and most hardworking people in #webperf (and beyond) and deserves our gratitude!

150

Robin Marx @programmingart.bsky.social · 10/12/2024

This year, I again had the honour of authoring the HTTP chapter of the Web Almanac: almanac.httparchive.org/en/2024/http It's full of interesting stats on technologies like HTTP/3, DNS HTTPS records, preloads, 103 Early Hints and the FetchPriority API. It also has Pirates 🏴‍☠️ and Marry Poppins 🌂!

almanac.httparchive.org

HTTP | 2024 | The Web Almanac by HTTP Archive

The HTTP chapter of the 2024 Web Almanac covers data on historical versions of HTTP used across the web, as well as the uptick in adoption of HTTP/2 and HTTP/3 from alt-svc and DNS HTTPS records. Addi...

23613

Reposted by Robin Marx

HTTP Archive 💾 @httparchive.org · 10/12/2024

The HTTP chapter was written by @programmingart.bsky.social and being our first name, is a subject close to our heart 😀 almanac.httparchive.org/en/2024/http Read it for lots of fascinating deep dive into to how web resources are delivered and the latest on how developers can influence that!

almanac.httparchive.org

HTTP | 2024 | The Web Almanac by HTTP Archive

131

Reposted by Robin Marx

Julia Evans @b0rk.jvns.ca · 07/12/2024

the blog post writeup of this is so good eieio.games/blog/writing...

225047

Reposted by Robin Marx

Barry Pollard @tunetheweb.com · 05/12/2024

Some of you complain that PageSpeed Insights is a bit unrealistically show for the Lighthouse test. The PSI servers are a bit underpowered so we're changing the throttling, which should make the Performance score go up when this rolls out in the next few weeks. github.com/GoogleChrome... 🧵 1/5

github.com

Release v12.2.3 · GoogleChrome/lighthouse

Full Changelog This release is only for PageSpeed Insights and we expect it to ship within 2 weeks. Notable Changes The CPU throttling factor for PageSpeed Insights has been adjusted (#16256) to ac...

45618

Reposted by Robin Marx

Manuel Matuzović @matuzo.at · 01/12/2024

It's December 1st, and you know what that means: For the next 24 days, we'll publish articles about HTML by 24 authors. You can read them on the website or subscribe to the RSS channel. Enjoy! htmhell.dev/adventcalend...

htmhell.dev

HTMHell Advent Calendar 2024 - HTMHell

An article, talk, or tool that focuses on HTML every day until Christmas.

2288123

Reposted by Robin Marx

Tim Vereecke @timvereecke.bsky.social · 27/11/2024

My #wls2024 talk is available! I delved into advanced tuning techniques to make a modern website lightning fast. Using lots of charts and data, I showed how they helped make scalemates the fastest (and largest) modeling website in the world. www.youtube.com/watch?v=rjUr... #webperf

youtube.com

Beyond the basics, pushing the limits of webperf — Tim Vereecke

YouTube video by We Love Speed

173

Robin Marx @programmingart.bsky.social · 26/11/2024

Not that I know of no... Would actually be quite interesting to have that as a signal imo... @tunetheweb.com @patmeenan.com

110

Robin Marx @programmingart.bsky.social · 26/11/2024

It's Fastly and QUIC.cloud, as detailed in the paper linked on the bottom of that slide: jherbots.info/public_media... Note that this is only for HTTP/3. I also have some tests for HTTP/2 (which is still equally broken on some servers) but haven't made anything public for that yet.

110

Robin Marx @programmingart.bsky.social · 26/11/2024

1. Yeah, could be, didn't really dig super-deep into this one yet because it felt so inconsistent. 2. this was actually SO MUCH HARDER THAN IT LOOKS. I was practicing in my hotel room all night before... luckily I think @guaca.bsky.social has some skills here, so you can book us as a double act ;)

120

Robin Marx @programmingart.bsky.social · 26/11/2024

Here, I think Safari just falls back to normal tight mode logic: it's still in tight mode, but there's just 1 high-prio resource in flight (the 3rd CSS that's slow to load), so it starts loading low-prio stuff, but only 1 at a time. I don't think this is a special case due to stylesheets.

030

Robin Marx @programmingart.bsky.social · 26/11/2024

This talk is complementary to my talk at @perfnow.bsky.social last year 👇 on resource prioritization, where I didn't have time to fit in the "tight mode" details (they were enough for a whole new talk by themselves!) Big thanks to @patmeenan.com in particular for all his help (and work!) on this.

youtube.com

Resource Loading at the Cutting Edge | Robin Marx | performance.now() 2023

YouTube video by Web Conferences Amsterdam

141

Robin Marx @programmingart.bsky.social · 26/11/2024

These differences can be quite stark, such as in the screenshot below, where 1 simple Web page is loaded completely differently in the 3 main browsers... This means it's difficult to build pages that perform consistently well across them, and features like fetchpriority and preload don't help much 🤡

100

Robin Marx @programmingart.bsky.social · 26/11/2024

My talk from this year's We Love Speed is on YouTube! 👇 In "Tight Mode: how browsers REALLY load web pages", I take a very deep/very nerdy dive into why browsers sometimes intentionally delay loading resources, why they all do it differently, and why they should *stop clowning around* 🤡 #webperf

youtube.com

How browsers REALLY load Web pages — Robin Marx

YouTube video by We Love Speed

54220

Robin Marx @programmingart.bsky.social · 25/11/2024

I've submitted two proposals for this: - How browsers REALLY load web pages - A First Foray into Compression Dictionaries You, dear reader, should also submit something 😉

221

Robin Marx @programmingart.bsky.social · 25/11/2024

I've done a lot of research myself exposing inconsistencies in browser/server implementations of "standardized" features. Below is another excellent example of how even cookies are broken to an incomprehensible degree... all without being properly documented. We need to start doing better.

030

Robin Marx @programmingart.bsky.social · 20/11/2024

Finally, to add credence to others here seeing high iOS usage: I help curate www.rumarchive.org, which aggregates real user data from top Akamai customers worldwide. Our traffic leans heavily towards iOS (61%) with webkit-browsers accounting for 51%+ of all requests (rumarchive.com/insights/#os...)

030

Robin Marx @programmingart.bsky.social · 20/11/2024

People focus too much on just optimizing for Chromium right now, assuming good results there automatically transfer over to safari/webkit, but with no way to really validate. This all to help you answer "why are numbers for one browser not enough?": because you can't extrapolate between them.

130

Robin Marx @programmingart.bsky.social · 20/11/2024

My expertise is in networking (protocols, resource download scheduling and prioritization) and I've found many cases of low-level differences between browsers that are undocumented and hard to diagnose (some examples here: youtu.be/MV034VqHv5Q?...).

youtu.be

Resource Loading at the Cutting Edge | Robin Marx | performance.now() 2023

YouTube video by Web Conferences Amsterdam

110