Robin Marx has been asking me for a Compression Dictionary Transport (RFC 9842) test tool for a long time (since well before AI was actually useful for this...

On 19th and 20th of November 2026, the seventh edition of performance.now() will take place in Amsterdam—a single track conference, covering today’s most important web performance insights.

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

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,...

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,...

This document specifies a mechanism for dictionary-based compression in the Hypertext Transfer Protocol (HTTP). By utilizing this technique, clients and servers can reduce the size of transmitted data...

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

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...

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...

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...

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...

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...

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...

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

YouTube video by We Love Speed

YouTube video by We Love Speed

Passionate about a topic? Working on a new tool? Have a technique you want to teach? Research you've done? Tell the web performance community! Send your articles to ssttoo@ymail.com. Please include: ...

Passionate about a topic? Working on a new tool? Have a technique you want to teach? Research you've done? Tell the web performance community! Send your articles to ssttoo@ymail.com. Please include: ...

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What exactly is HTTP/3? Why was it needed so soon after HTTP/2 (which was only finalized in 2015)? How can or should you use it? And especially, how does this improve web performance? Let’s find out.