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Tim Kadlec

@tkadlec

Principal Product Manager @cloudflare—focused on performance and observability. Co-chair of https://perfnow.nl Taller than my photo looks.

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Latest posts by Tim Kadlec @tkadlec

The somewhat ironic part about all the backlog of code to review thanks to AI coding tools is that AI is _significantly_ better at code review than it is at code generation.

05.03.2026 14:38 👍 8 🔁 0 💬 1 📌 0

Live view of me waiting for this day...

Gonna be a lot of fun with some awesome stuff to come!

02.03.2026 23:23 👍 9 🔁 0 💬 0 📌 0

Do I know anyone, or does anyone I know know anyone, at eBay who I can chat with about some things I'm running into with their API's?

28.01.2026 14:59 👍 0 🔁 2 💬 0 📌 0

AI automated support bots are one of the worst plagues to infest the internet. They are truly awful, infuriating and useless 95% of the time.

Please, I am begging, just let me talk to a real person.

26.01.2026 21:40 👍 16 🔁 0 💬 2 📌 1

So far, AI has been considerably better at the illusion of utility and intelligence than at actual utility and intelligence.

14.01.2026 05:10 👍 2 🔁 0 💬 0 📌 0

AI will have to pry em dashes out of my cold dead hands

Interesting conversation I had with my kids recently: my high-school daughters actively avoid using "big" words in their writing because they get accused of using ChatGPT. Literally dumbing down their writing to avoid being accused of using AI

08.01.2026 16:21 👍 25 🔁 2 💬 1 📌 1

I do firmly believe that if you're an individual or company that is NOT over-indexing on AI right now, you have the competitive advantage.

Unfortunately I do not have high hopes that the industry will recognize that until significant damage has been done.

12.12.2025 14:51 👍 15 🔁 3 💬 0 📌 0

Will definitely be making sure it's available both as a CLI and something that can be deployed somewhere.

07.11.2025 13:11 👍 3 🔁 0 💬 0 📌 0

I heard you found them? :)

07.11.2025 13:10 👍 1 🔁 0 💬 1 📌 0

We're rewriting the Readme and that's definitely one of the changes in there. :)

07.11.2025 13:10 👍 1 🔁 0 💬 0 📌 0

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.

06.11.2025 19:57 👍 9 🔁 1 💬 0 📌 0

this checks out

problem is will I actually remember this come this time next year?

02.11.2025 23:45 👍 1 🔁 0 💬 1 📌 0

Phew ok you've got me beat this time. I've got another ~6 hours left. :)

01.11.2025 21:36 👍 0 🔁 0 💬 2 📌 0

I am so sincerely sorry for what I have done.

01.11.2025 11:02 👍 0 🔁 0 💬 1 📌 0

So fantastic to see you, as always Tammy. :) Have a safe trip home.

01.11.2025 11:02 👍 2 🔁 0 💬 1 📌 0

Appreciate it!

Please feel free to add issues for features, improvements, bugs, etc as you go! Or if you're particularly ambitious and bored, PR's. ;)

01.11.2025 11:01 👍 2 🔁 0 💬 0 📌 0

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.

01.11.2025 09:30 👍 14 🔁 0 💬 0 📌 0

performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.

01.11.2025 08:21 👍 27 🔁 7 💬 0 📌 0

Thanks, Philip. :)

Will get it merged.

31.10.2025 16:49 👍 0 🔁 0 💬 0 📌 0

just a couple old guys, yelling at things, us two

31.10.2025 14:49 👍 2 🔁 0 💬 1 📌 0
Post image

Always, always happy to see @yoav.ws get a shout-out. So much incredible work has happened because of him. Most recent example—speculation rules in WebKit. #perfnow

31.10.2025 14:18 👍 24 🔁 3 💬 1 📌 1
Preview
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.

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!

31.10.2025 14:15 👍 38 🔁 5 💬 5 📌 2
Preview
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 ...

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...

31.10.2025 13:57 👍 16 🔁 3 💬 2 📌 1
Michal Mocney presenting at perfnow about SPA heuristics, demoing being able to measure LCP and other metrics on soft navigations

Michal Mocney presenting at perfnow about SPA heuristics, demoing being able to measure LCP and other metrics on soft navigations

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

31.10.2025 10:41 👍 13 🔁 2 💬 0 📌 2
Preview
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 ssttoo@ymail.com. Please include: ...

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/

30.10.2025 16:59 👍 23 🔁 19 💬 2 📌 0

......

Valid

30.10.2025 18:38 👍 1 🔁 0 💬 1 📌 0

“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!

30.10.2025 11:19 👍 46 🔁 9 💬 1 📌 0
O

O

@inesakrap.bsky.social starting her #perfnow talk with Lego's and Bluey has me already a fan.

30.10.2025 13:48 👍 8 🔁 2 💬 0 📌 0
Preview
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…

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/...

30.10.2025 09:30 👍 11 🔁 6 💬 0 📌 0
Harry on the stage. Behind him, a slide that reads as follows:

"While a good TTFB doesn't necessarily mean you will have a fast website, a bad TTFB almost certainly guarantees a slow one."
— csswz.it/ttfb

Harry on the stage. Behind him, a slide that reads as follows: "While a good TTFB doesn't necessarily mean you will have a fast website, a bad TTFB almost certainly guarantees a slow one." — csswz.it/ttfb

Friendly reminder! #perfnow

30.10.2025 09:22 👍 7 🔁 2 💬 1 📌 0