Ever wanted a comprehensive guide to DevTools and debugging front ends? Check out this ebook that Lala Hakobyan just launched:
github.com/lala-hakobya...
I’m impressed!!
Interested in the @httparchive.org and not sure where to start? During the @performanceobserver.dev meetup tomorrow (12:30pm ET), I'm going to be providing an overview of the HTTP Archive and demonstrate how to start querying it! performanceobserver.dev/events/episo...
I’ll be giving a talk about Fonts and Web Perfomance at the Tech SEO Summit in Hamburg, Germany on April 23rd. They have only a few tickets remaining if anyone wants to attend! tech-seo-summit.com
A shocking 8.5% of sites that use CDNs deliver some static content directly to end users via cloud storage! Many are not compressing or caching this content either. This comes at a significant performance cost. Details, examples and @httparchive.org stats here - paulcalvano.com/2026-02-09-s...
Tomorrow at 6pm the @nywebperf.com meetup is running another in person "Meet for Speed" session. We take requests from attendees for sites to do a webperf analysis on. @fastly.com is hosting us at their office in Union Square.
Have a site you'd like us to analyze? bit.ly/meet4speed-s...
The 2025 Web Almanac by HTTP Archive has been officially released! 🚀
We would like to thank all of our contributors from around the globe who made this extensive report possible!
Check out the full report here: almanac.httparchive.org
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!
New @httparchive.org analysis about sites adding AI Bots and Crawlers to their robots.txt files. While robots.txt doesn't "block" bots by itself, it's a clear demonstration of the preferences of site owners and the sentiment towards AI crawlers on today's web. paulcalvano.com/2025-08-21-a...
This Thursday at 6pm the NYC WebPerf Meetup is running another in person "Meet for Speed" session. We'll be taking requests from attendees for sites to do a web performance analysis on.
www.meetup.com/web-performa...
Have a site you'd like us to analyze? Add it here - bit.ly/meet4speed-s...
Tonight at 6pm the NYC WebPerf Meetup is running another in person "Meet for Speed" session. We'll be taking requests from attendees for sites to do a web performance analysis on. Fastly will be hosting us at their NYC office.
www.meetup.com/web-performa...
The video of my talk from the Performance Now conference in Amsterdam was posted today. #perfnow
This Friday afternoon I'll be at the Boston Web Performance meetup giving my talk on "Performance Mistakes". If you are in the Boston area and interested in web performance, join us!
www.meetup.com/boston-web-p...
If you missed @paulcalvano.bsky.social at @perfnow.bsky.social, and happen to be in the Boston area next week, he'll be speaking at the Boston Web Performance December meetup.
Sign up on meetup: www.meetup.com/boston-web-p...
December 6th ∘ 4:30pm ∘ Akamai HQ in Cambridge.
#webperf #perfmatters
If you want the output of the query I can send that so that you don’t have to run it!
Here's the query for that. I added a few comments to help explain it as well. The query will output 5 examples for each third party as well. console.cloud.google.com/bigquery?sq=...
Hey - thanks! Happy to share. I don't have them all neatly organized right now, but plan to write a few blog posts with all the details and queries. In the meantime, if there are any particular queries you are interested in let me know and I'll send them over!
Just posted them - bsky.app/profile/paul...
Can anyone think of other web performance mistakes that you suspect might be occuring on a lot of sites? We might be able to query that in the @httparchive.org too, and I'd be happy to help you get started if you are interested in exploring the dataset!
Oh, and I made mistake in my talk about mistakes :). Apparently async image decoding isn’t that big of a deal for high priority images. So ignore #3 from my list, and check out @tunetheweb.com's blog post about that here - www.tunetheweb.com/blog/what-do...
A few attendees told me they found some of these mistakes on their websites while we were still at the conference! So now they can be considered performance opportunities :)
Last week I gave a talk at the #PerfNow conference titled “Performance Mistakes”. I started off explaining a bit about Etsy’s blameless culture, and how it’s ok to make mistakes. Then I shared 17 common #webperf mistakes using @httparchive.org data, with examples.
www.slideshare.net/slideshow/pe...
Hey! Thanks Marc. I’ll be posting them later today. Will let you know once they are up!
Seriously. It's such a breath of fresh air!
Great start to #perfnow this year with @tammyeverts.bsky.social and @csswizardry.com !
For those of you looking for the general web perf starter pack, here it is! Lots of new folks since last time I shared it
go.bsky.app/RVWSVqe
The all new performance chapter of the 2024 Web Almanac written by Jevgenija Zigisova and @inesakrap.bsky.social
almanac.httparchive.org/en/2024/perf...
I wrote a blog post that goes into detail on this: paulcalvano.com/2024-03-19-c...
TLDR: if you are serving any dynamically generated responses on the server, then gzip level 6 or brotli 5 are reasonable defaults. If you -only- serve static cacheable resources then turn it up all the way.
Fellow #perfnow attendee, the PerfPlanet advent calendar is looking for articles for the 2024 edition. Please come talk to me if you’re considering an idea for a post but you’re not sure and you need a second opinion calendar.perfplanet.com/contribute/
Took 2 mins at #PerfNow to talk about the RUM Community Group in W3C for anyone doing RUM. It's free and easy to join if you're interested! www.w3.org/community/ru...
Such a great talk! Thank you so much for sharing. And it was great to meet you this week!
Yesterday during my #perfnow talk, I mentioned the Web Performance Slack. If you’d like to join the Slack, use this link before Nov 25: join.slack.com/t/webperf…
