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.
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
@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.
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.
👀 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...
Lake Superior remains undefeated
June 22, 2025 at 1:48 AM
Lake Superior remains undefeated
Been wondering why a bunch of sites have been SUPER slow lately.
Turns out it's the @1password.bsky.social chrome extension doing really bad things. :/
Gonna have to disable for awhile.
Turns out it's the @1password.bsky.social chrome extension doing really bad things. :/
Gonna have to disable for awhile.
January 31, 2025 at 8:28 PM
Been wondering why a bunch of sites have been SUPER slow lately.
Turns out it's the @1password.bsky.social chrome extension doing really bad things. :/
Gonna have to disable for awhile.
Turns out it's the @1password.bsky.social chrome extension doing really bad things. :/
Gonna have to disable for awhile.
Basically doing the same thing.
December 14, 2024 at 4:01 PM
Basically doing the same thing.
"Always iterate". @anniesullie.bsky.social
Good advice for product management, performance experimentation and so much more.
I'm a huge proponent of the "what's the least amount of work we can do to see if we're on the right path" approach.
#perfnow
Good advice for product management, performance experimentation and so much more.
I'm a huge proponent of the "what's the least amount of work we can do to see if we're on the right path" approach.
#perfnow
November 15, 2024 at 4:49 PM
"Always iterate". @anniesullie.bsky.social
Good advice for product management, performance experimentation and so much more.
I'm a huge proponent of the "what's the least amount of work we can do to see if we're on the right path" approach.
#perfnow
Good advice for product management, performance experimentation and so much more.
I'm a huge proponent of the "what's the least amount of work we can do to see if we're on the right path" approach.
#perfnow
Friendly reminder that when a third-party provider requires you to load their script in a render-blocking manner, their problems become your problems.
Always build with resilience in mind.
Always build with resilience in mind.
August 2, 2023 at 2:27 PM
Friendly reminder that when a third-party provider requires you to load their script in a render-blocking manner, their problems become your problems.
Always build with resilience in mind.
Always build with resilience in mind.
Started working with these folks in mid-May and not gonna lie, pretty pleased with the progress they've made on INP in such a short span of time.
From a p75 of 4.25s in April (90% of sessions having a poor experience) to a p75 of 225ms in June (9% of sessions have a poor experience).
From a p75 of 4.25s in April (90% of sessions having a poor experience) to a p75 of 225ms in June (9% of sessions have a poor experience).
July 14, 2023 at 4:58 PM
Started working with these folks in mid-May and not gonna lie, pretty pleased with the progress they've made on INP in such a short span of time.
From a p75 of 4.25s in April (90% of sessions having a poor experience) to a p75 of 225ms in June (9% of sessions have a poor experience).
From a p75 of 4.25s in April (90% of sessions having a poor experience) to a p75 of 225ms in June (9% of sessions have a poor experience).
Phew. What a difference a `:last` makes in jQuery. Third-party Shopify app with a very long list of selectors in a click handler.
With the deprecated `:last` selector: ~616ms
Without: ~16ms
(Talked to the app devs and they're looking at it now so hopefully this gets fixed)
With the deprecated `:last` selector: ~616ms
Without: ~16ms
(Talked to the app devs and they're looking at it now so hopefully this gets fixed)
June 8, 2023 at 2:53 PM
Phew. What a difference a `:last` makes in jQuery. Third-party Shopify app with a very long list of selectors in a click handler.
With the deprecated `:last` selector: ~616ms
Without: ~16ms
(Talked to the app devs and they're looking at it now so hopefully this gets fixed)
With the deprecated `:last` selector: ~616ms
Without: ~16ms
(Talked to the app devs and they're looking at it now so hopefully this gets fixed)