Tim Kadlec
@tkadlec.bsky.social
Principal Product Manager @cloudflare—focused on performance and observability.
Co-chair of https://perfnow.nl
Taller than my photo looks.
Co-chair of https://perfnow.nl
Taller than my photo looks.
Reposted by Tim Kadlec
Very happy to work on a tool like that with @tkadlec.bsky.social and the team!
Please try it out and post the issues and PRs.
Please try it out and post the issues and PRs.
Telescope, the new cross-browser performance testing agent I mentioned at #perfnow that we @cloudflare.social have open-sourced is here: github.com/cloudflare/t...
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
GitHub - cloudflare/telescope: Cross-browser web performance testing agent
Cross-browser web performance testing agent. Contribute to cloudflare/telescope development by creating an account on GitHub.
github.com
November 6, 2025 at 11:41 PM
Very happy to work on a tool like that with @tkadlec.bsky.social and the team!
Please try it out and post the issues and PRs.
Please try it out and post the issues and PRs.
At the airport heading back after another incredible #perfnow.
Each year, I'm reminded of how fortunate I am to be a part of the performance community. So many wonderful, kind, smart people all working together to make the web better.
Already looking forward to next year.
Each year, I'm reminded of how fortunate I am to be a part of the performance community. So many wonderful, kind, smart people all working together to make the web better.
Already looking forward to next year.
November 1, 2025 at 9:30 AM
At the airport heading back after another incredible #perfnow.
Each year, I'm reminded of how fortunate I am to be a part of the performance community. So many wonderful, kind, smart people all working together to make the web better.
Already looking forward to next year.
Each year, I'm reminded of how fortunate I am to be a part of the performance community. So many wonderful, kind, smart people all working together to make the web better.
Already looking forward to next year.
Reposted by Tim Kadlec
performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.
November 1, 2025 at 8:21 AM
performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.
Telescope, the new cross-browser performance testing agent I mentioned at #perfnow that we @cloudflare.social have open-sourced is here: github.com/cloudflare/t...
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
GitHub - cloudflare/telescope: Cross-browser web performance testing agent
Cross-browser web performance testing agent. Contribute to cloudflare/telescope development by creating an account on GitHub.
github.com
October 31, 2025 at 2:15 PM
Telescope, the new cross-browser performance testing agent I mentioned at #perfnow that we @cloudflare.social have open-sourced is here: github.com/cloudflare/t...
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
We want this to be a tool the entire community is able to contribute to and benefit from, so please help us make it better!
I appreciate everyone at #perfnow letting me have my "old man yells at cloud" moment this morning.
Slides are now up: noti.st/tkadlec/3imH...
Slides are now up: noti.st/tkadlec/3imH...
Stubborn Empathy by Tim Kadlec
One of the most important roles we play on the web is as the users line of defense, which requires that we demonstrate stubborn empathy on their behalf. Unfortunately, that concept is all too easy to ...
noti.st
October 31, 2025 at 1:57 PM
I appreciate everyone at #perfnow letting me have my "old man yells at cloud" moment this morning.
Slides are now up: noti.st/tkadlec/3imH...
Slides are now up: noti.st/tkadlec/3imH...
I have been sooooo looking forward to this! SPA heuristics are gonna be such a huge step forward for measuring perf on the web and finally having hard data on the perf impact.
@mmocny.com #perfnow
@mmocny.com #perfnow
October 31, 2025 at 10:41 AM
I have been sooooo looking forward to this! SPA heuristics are gonna be such a huge step forward for measuring perf on the web and finally having hard data on the perf impact.
@mmocny.com #perfnow
@mmocny.com #perfnow
Reposted by Tim Kadlec
Fellow #perfnow fellows, a reminder that PerfPlanet calendar is coming this December for another edition. And it needs YOU. Please ask if you have any contribution ideas or concerns calendar.perfplanet.com/contribute/
Contribute
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 [email protected]. Please include:
...
calendar.perfplanet.com
October 30, 2025 at 4:59 PM
Fellow #perfnow fellows, a reminder that PerfPlanet calendar is coming this December for another edition. And it needs YOU. Please ask if you have any contribution ideas or concerns calendar.perfplanet.com/contribute/
Reposted by Tim Kadlec
“We should treat accessibility as something that is structural or baked in or part of the DNA, if we want to be successful”
— says @marcysutton.com at #perfnow
“Don’t treat it like trying to put chocolate chips into a cookie after it is baked”
I love this framing!
— says @marcysutton.com at #perfnow
“Don’t treat it like trying to put chocolate chips into a cookie after it is baked”
I love this framing!
October 30, 2025 at 11:19 AM
“We should treat accessibility as something that is structural or baked in or part of the DNA, if we want to be successful”
— says @marcysutton.com at #perfnow
“Don’t treat it like trying to put chocolate chips into a cookie after it is baked”
I love this framing!
— says @marcysutton.com at #perfnow
“Don’t treat it like trying to put chocolate chips into a cookie after it is baked”
I love this framing!
@inesakrap.bsky.social starting her #perfnow talk with Lego's and Bluey has me already a fan.
October 30, 2025 at 1:48 PM
@inesakrap.bsky.social starting her #perfnow talk with Lego's and Bluey has me already a fan.
Reposted by Tim Kadlec
Slides from my @perfnow.nl talk — How Fast Is Fast Enough? — are up!
If you’re at #PerfNow (or even if you’re not) I’d love to talk about creating a delightful experience for your users.
speakerdeck.com/tammyeverts/...
If you’re at #PerfNow (or even if you’re not) I’d love to talk about creating a delightful experience for your users.
speakerdeck.com/tammyeverts/...
How Fast Is Fast Enough? [PerfNow 2025]
It sounds like a simple question, but if you've been working in web performance long enough, you know the answer is far from straightforward. In this ke…
speakerdeck.com
October 30, 2025 at 9:30 AM
Slides from my @perfnow.nl talk — How Fast Is Fast Enough? — are up!
If you’re at #PerfNow (or even if you’re not) I’d love to talk about creating a delightful experience for your users.
speakerdeck.com/tammyeverts/...
If you’re at #PerfNow (or even if you’re not) I’d love to talk about creating a delightful experience for your users.
speakerdeck.com/tammyeverts/...
Reposted by Tim Kadlec
October 30, 2025 at 8:48 AM
Reposted by Tim Kadlec
It is Friday, end of week. A good time to grab your ticket for #btconf Berlin. 3 weeks to go and we still have seats available. Full list of #speakers, their #talks and #schedule here on our website. beyondtellerrand.com/events/berli...
beyond tellerrand // BERLIN 2025, taking place 06 - 07 Nov 2025
beyond tellerrand 2025 in Berlin. Join us on 06 - 07 Nov 2025 for talks about web, design, technology, typography and much more. In the renowned friendly atmosphere.
beyondtellerrand.com
October 17, 2025 at 9:28 AM
It is Friday, end of week. A good time to grab your ticket for #btconf Berlin. 3 weeks to go and we still have seats available. Full list of #speakers, their #talks and #schedule here on our website. beyondtellerrand.com/events/berli...
Ridiculously clever from @scottjehl.com
October 15, 2025 at 9:39 PM
Ridiculously clever from @scottjehl.com
This is super exciting, particularly knowing Safari has it in Tech Preview so we're _this_ close to having it cross-browser.
Also fun to watch the rollout through the lens of Cloudflare's Web Analytics.
Also fun to watch the rollout through the lens of Cloudflare's Web Analytics.
October 15, 2025 at 6:04 PM
This is super exciting, particularly knowing Safari has it in Tech Preview so we're _this_ close to having it cross-browser.
Also fun to watch the rollout through the lens of Cloudflare's Web Analytics.
Also fun to watch the rollout through the lens of Cloudflare's Web Analytics.
If your industry would die if you did the right thing perhaps it's not a good industry?
Nick Clegg says asking artists for use permission would ‘kill’ the AI industry
Nick Clegg says asking artists for use permission would ‘kill’ the AI industry
Paul McCartne, Elton John and others signed an open letter.
buff.ly
October 8, 2025 at 9:22 PM
If your industry would die if you did the right thing perhaps it's not a good industry?
New case study on wpostats.com
Relive improved LCP by 50% and cut out layout shifts and saw a 3% increase in conversion rate, 6% decrease in bounce rate and 9% increase in page views per session.
wpostats.com/2025/10/02/r...
Relive improved LCP by 50% and cut out layout shifts and saw a 3% increase in conversion rate, 6% decrease in bounce rate and 9% increase in page views per session.
wpostats.com/2025/10/02/r...
October 2, 2025 at 3:15 PM
New case study on wpostats.com
Relive improved LCP by 50% and cut out layout shifts and saw a 3% increase in conversion rate, 6% decrease in bounce rate and 9% increase in page views per session.
wpostats.com/2025/10/02/r...
Relive improved LCP by 50% and cut out layout shifts and saw a 3% increase in conversion rate, 6% decrease in bounce rate and 9% increase in page views per session.
wpostats.com/2025/10/02/r...
Been a hot minute, but working through some of the case studies that were submitted to wpostats.com but not yet put live.
Starting with a pair of INP-relevant studies from PubTech and ContentSquare. wpostats.com/2025/09/15/p... & wpostats.com/2025/09/15/c...
Starting with a pair of INP-relevant studies from PubTech and ContentSquare. wpostats.com/2025/09/15/p... & wpostats.com/2025/09/15/c...
Consent Management Platforms (CMPs) are tools that help websites comply with privacy regulations by obtaining user consent for the use of cookies and tracking technologies. In addition to the primary ...
wpostats.com
September 15, 2025 at 4:22 PM
Been a hot minute, but working through some of the case studies that were submitted to wpostats.com but not yet put live.
Starting with a pair of INP-relevant studies from PubTech and ContentSquare. wpostats.com/2025/09/15/p... & wpostats.com/2025/09/15/c...
Starting with a pair of INP-relevant studies from PubTech and ContentSquare. wpostats.com/2025/09/15/p... & wpostats.com/2025/09/15/c...
👀 Safari plans to ship LCP and INP in 2025?! Be still my beating heart. webkit.org/blog/16458/a...
July 2, 2025 at 1:15 PM
👀 Safari plans to ship LCP and INP in 2025?! Be still my beating heart. webkit.org/blog/16458/a...
This is incredible data from @dbelson.com showing HTML requests from crawlers versus referrals from that platform. Very easy to see the cost of AI here.
ClaudeBot: 70.9k requests : 1 referral (!!!)
OpenAI: 1.6K : 1
Perplexity: 202.4 : 1
blog.cloudflare.com/ai-search-cr...
ClaudeBot: 70.9k requests : 1 referral (!!!)
OpenAI: 1.6K : 1
Perplexity: 202.4 : 1
blog.cloudflare.com/ai-search-cr...
July 1, 2025 at 3:30 PM
This is incredible data from @dbelson.com showing HTML requests from crawlers versus referrals from that platform. Very easy to see the cost of AI here.
ClaudeBot: 70.9k requests : 1 referral (!!!)
OpenAI: 1.6K : 1
Perplexity: 202.4 : 1
blog.cloudflare.com/ai-search-cr...
ClaudeBot: 70.9k requests : 1 referral (!!!)
OpenAI: 1.6K : 1
Perplexity: 202.4 : 1
blog.cloudflare.com/ai-search-cr...
Pumped for this. The line-up is stacked (with more coming soon) & the community around the event has gotten better and better each year with amazing conversations throughout, side events, large standards & browser involvement—it's wild to think about how this has taken off from its 1st year.
performance.now(), the web performance conference, 30th and 31st of October, Amsterdam. Single track, the best speakers in the industry, plenty of your performance-mad peers around to have fascinating conversations. What's not to like? Let's introduce our speakers ...
perfnow.nl
perfnow.nl
performance.now(); 30th and 31st of October, Amsterdam
On 30th and 31st of October, 2025, the sixth edition of performance.now() will take place in Amsterdam—a single track conference, covering today’s most important web performance insights.
perfnow.nl
June 26, 2025 at 2:08 PM
Pumped for this. The line-up is stacked (with more coming soon) & the community around the event has gotten better and better each year with amazing conversations throughout, side events, large standards & browser involvement—it's wild to think about how this has taken off from its 1st year.
Lake Superior remains undefeated
June 22, 2025 at 1:48 AM
Lake Superior remains undefeated
For those of you who watched my talk at @webexpo.bsky.social, the bug I mentioned regarding speculation rules and GET/POST looks like it should be fixed in Chrome v138. chromium-review.googlesource.com/c/chromium/s...
h/t @tunetheweb.com
h/t @tunetheweb.com
Gerrit Code Review
chromium-review.googlesource.com
June 6, 2025 at 12:53 PM
For those of you who watched my talk at @webexpo.bsky.social, the bug I mentioned regarding speculation rules and GET/POST looks like it should be fixed in Chrome v138. chromium-review.googlesource.com/c/chromium/s...
h/t @tunetheweb.com
h/t @tunetheweb.com
Reposted by Tim Kadlec
Thanks again to everyone who came to my #WebExpo talk about the intersection of site speed, #UX and business metrics – and how to make a data-driven business case for investing in #webperf.
My slides are up. I'd love to hear your questions and feedback!
speakerdeck.com/tammyeverts/...
My slides are up. I'd love to hear your questions and feedback!
speakerdeck.com/tammyeverts/...
Connecting the Dots Between Site Speed, User Experience & Your Business [WebExpo 2025]
What do the most successful websites have in common? They’re all fast. Faster sites have happier users. Those happy users visit your site more often and…
speakerdeck.com
May 30, 2025 at 8:11 AM
Thanks again to everyone who came to my #WebExpo talk about the intersection of site speed, #UX and business metrics – and how to make a data-driven business case for investing in #webperf.
My slides are up. I'd love to hear your questions and feedback!
speakerdeck.com/tammyeverts/...
My slides are up. I'd love to hear your questions and feedback!
speakerdeck.com/tammyeverts/...