Documentation: techdocs.akamai.com/property-mgr...

Sometimes, legacy applications use POST instead of GET to retrieve data. On Akamai, you can easily force caching of specific POST responses to improve both offload and performance.

In the screenshot below, you can see the first (slow) and subsequent data retrievals using POST (fast, cached).

Screenshot of a performance trace in Chrome DevTools with a few additional "Nav*" and "LCP*" markers. Hovering over the "LCP*" shows this is a "Soft LCP" and in the Summary panel when you click on it you see "Soft Largest Contentful Paint" and a "Learn more about Soft Largest Contentful Paint" link.

From Chrome 145 (on general release next week!), DevTools we will start to show so called "soft" navigations and "Soft LCP" in the Performance Panel traces.

These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry.

1/5 🧵

I registered for the origin trial and it works as expected. I no longer see any JS based changes or requests when using prerender_until_script. thx!

Speculation rules prerender until script origin trial  |  Blog  |  Chrome for Developers Learn about the new prerender until script option for the Speculation Rules API, now available in origin trial.

Think prefetch is not enough, but prerender is too risky for your site?

Well then check out "prerender until script"—a new option we're testing for the Speculation Rules API now available for you to test on your site with an origin trial!
developer.chrome.com/blog/prerend...

Jquery 4.0.0 is out, great byte savings in the latest release #webperf

🆕 The 202511 Chrome User Experience (CrUX) release is now live on BigQuery!

Check out the announcement post for the full info:
groups.google.com/a/chromium.o...

Highlights below 👇

🧵 1/3

@searchliaison.bsky.social I spotted this on 2 different sites and 2 different CDN's. Is this a common pattern or is it linked to individual sites?

Anyone else seeing a degradation of Average Download time (+90ms ish) in Google Crawl Stats that started on(Around) September 24th?

#webperf #crawler

thx Michal! it was a great presentation

The new SVG hack? (Context: The lack of preconnect/preload means there is 0.000 performance impact for the user)

Gaming the system? Lack of knowledge? Or is there a benefit not linked to #webperf?

Heard about this at @perfnow.nl

103 Early Hints is now supported by more than 92% of all users.

When done right, it is a great way to improve your higher percentiles of FCP and LCP

#webperf

That was Desktop only! above is for ”all”

Scalemates was used by @tunetheweb.com as an example of how fast a site can be using the Speculation Rules API.

It has an LCP of 483ms at the P75!

#webperf

Why is my site fast?

55% of my pageviews on Desktop are coming from Bfbache or had an early start with Prerendering. 👌

#webperf is easy* in 2025

(*I know I know)

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...

Unattributed Navigation Overhead (UNO)

calendar.perfplanet.com/2024/uno/ by @timvereecke.bsky.social

#WebPerf #Performance

Why is my site fast?

55% of my pageviews on Desktop are coming from Bfbache or had an early start with Prerendering. 👌

#webperf is easy* in 2025

(*I know I know)

Amazing (and simple) technique by @kilianvalkhof.com .

autofocus is a great way to make your login/registration and password reset forms more user-friendly

htmhell.dev/adventcalend...

I implemented it during my lunch break... so much better!

#UX #htmhell

Tim Vereecke at performance.sync() YouTube video by Web Conferences Amsterdam

Great stuff. I just watched a talk from @timvereecke.bsky.social that covered the redirects, and I was surprised how big an impact they can have on TTFB.

Time to track redirects in my RUM data (when possible). youtu.be/E2E89NeBbEM?...

They should invent a CLS score for slide decks!

#webperf #presentations

Excellent! Much needed improvement

Definitely A

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 ...

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...

Tim Vereecke at performance.sync() YouTube video by Web Conferences Amsterdam

Have you ever noticed unexplainable performance degradations? Unattributed Navigation Overhead (UNO) is probably the missing link. Watch my Lightning Talk from the performance.sync() meetup in Amsterdam!

#webperf #rum #ttfb #cwv

www.youtube.com/watch?v=E2E8...

Amazing article! Will instantly apply it to my facetted navigation with sometimes 1000+ iterations, one for each filter

Wait? What? Web Performance Optimization is being studied in universities? TL;DR: In this article I am sharing the good news that Web Performance Optimization is being studied in universities and I am laying out the plan of teaching Real User Monitoring which I will do for t...

Web performance calendar day 28 with Tsvetan Stoychev's curriculum for teaching Real User Monitoring. Cup of rum? Sign me up!

calendar.perfplanet.com/2024/wait-wh...

This article is such a gem! And the talk at Performance.sync() was too:

youtu.be/E2E89NeBbEM?...

Special thanks to @programmingart.bsky.social for the review and suggestions!

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...

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/

Ready to make your sites load like 🚀? Join our latest livestream with @timvereecke.bsky.social where we dive deep into the Speculation Rules API! 🎥

What’s in it:
- Pre-rendering & Prefetching Magic
- Real-World Use Cases
- Simple to complex use-case

Catch the action on YouTube: dub.sh/MyXjkeC