juan ferreras
@juanf.is
Engineer by day, over-engineer by night. Passionate about #webperf.
Prev: co-founded #LabelRadar (acq.)
Prev: co-founded #LabelRadar (acq.)
Pinned
juan ferreras
@juanf.is
· May 7
Here's an example on quickly prototyping a change and measuring the before/after in just a few minutes.
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵
Reposted by juan ferreras
I spent hours and hours trawling through the sites of some of the world's best web developers, and despite the horrors I regularly experience in my daily work in Big JavaScript Territory, what I saw left me hopeful:
infrequently.org/2025/07/links/
infrequently.org/2025/07/links/
Links? Links! - Infrequently Noted
Alex Russell on browsers, standards, and the process of progress.
infrequently.org
July 16, 2025 at 11:17 PM
I spent hours and hours trawling through the sites of some of the world's best web developers, and despite the horrors I regularly experience in my daily work in Big JavaScript Territory, what I saw left me hopeful:
infrequently.org/2025/07/links/
infrequently.org/2025/07/links/
Reposted by juan ferreras
bluesky won't enable this switch by default, but you should.
today's a great day to make sure "require alt text before posting" is enabled in your settings and to continue to make bluesky more accessible and inclusive bsky.app/settings/acc...
July 9, 2025 at 2:54 PM
bluesky won't enable this switch by default, but you should.
Reposted by juan ferreras
I'm looking to recruit talented senior engineers that have experience related to web performance monitoring and optimization. If that sounds like you—or someone you'd highly recommend—please send me a DM and I’ll share more details!
The role is 100% remote and async-first.
The role is 100% remote and async-first.
July 9, 2025 at 11:27 AM
I'm looking to recruit talented senior engineers that have experience related to web performance monitoring and optimization. If that sounds like you—or someone you'd highly recommend—please send me a DM and I’ll share more details!
The role is 100% remote and async-first.
The role is 100% remote and async-first.
Reposted by juan ferreras
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...
This sounds super interesting.
I'm a bit skeptical on how unit economics would work – but compared to we'll-try-to-scrape-everything-we-can-unless-you-can-sue-us-or-fully-block-us, it feels like a great alternative.
Would love to see any leading provider send a positive signal..
I'm a bit skeptical on how unit economics would work – but compared to we'll-try-to-scrape-everything-we-can-unless-you-can-sue-us-or-fully-block-us, it feels like a great alternative.
Would love to see any leading provider send a positive signal..
Pay per crawl is a new feature to allow content creators to charge AI crawlers for access to their content. blog.cloudflare.com/introducing-...
Introducing Pay per crawl- enabling content owners to charge AI crawlers for access
Pay per crawl is a new feature to allow content creators to charge AI crawlers for access to their content.
blog.cloudflare.com
July 1, 2025 at 3:48 PM
This sounds super interesting.
I'm a bit skeptical on how unit economics would work – but compared to we'll-try-to-scrape-everything-we-can-unless-you-can-sue-us-or-fully-block-us, it feels like a great alternative.
Would love to see any leading provider send a positive signal..
I'm a bit skeptical on how unit economics would work – but compared to we'll-try-to-scrape-everything-we-can-unless-you-can-sue-us-or-fully-block-us, it feels like a great alternative.
Would love to see any leading provider send a positive signal..
Cloudflare's Containers are now in public beta.
blog.cloudflare.com/containers-a...
I was recently struggling to get a WASM version of brotli dictionary_generator (skill issue), but it's a very powerful unlock to just deploy a dockerfile if you need any specific runtime/CPU-intensive work
blog.cloudflare.com/containers-a...
I was recently struggling to get a WASM version of brotli dictionary_generator (skill issue), but it's a very powerful unlock to just deploy a dockerfile if you need any specific runtime/CPU-intensive work
Containers are available in public beta for simple, global, and programmable compute
Cloudflare Containers are now available in public beta. Deploy simple, global, and programmable containers alongside your Workers.
blog.cloudflare.com
June 24, 2025 at 4:32 PM
Cloudflare's Containers are now in public beta.
blog.cloudflare.com/containers-a...
I was recently struggling to get a WASM version of brotli dictionary_generator (skill issue), but it's a very powerful unlock to just deploy a dockerfile if you need any specific runtime/CPU-intensive work
blog.cloudflare.com/containers-a...
I was recently struggling to get a WASM version of brotli dictionary_generator (skill issue), but it's a very powerful unlock to just deploy a dockerfile if you need any specific runtime/CPU-intensive work
Free users can now write and deploy their own worker for experiments/prototyping changes.
If users could be limited by the pre-made recipes not being powerful enough – you can pretty much do anything now.
Finally back on the routine, it's time to play with Shared Compression Dictionaries now!
If users could be limited by the pre-made recipes not being powerful enough – you can pretty much do anything now.
Finally back on the routine, it's time to play with Shared Compression Dictionaries now!
June 18, 2025 at 1:34 PM
Free users can now write and deploy their own worker for experiments/prototyping changes.
If users could be limited by the pre-made recipes not being powerful enough – you can pretty much do anything now.
Finally back on the routine, it's time to play with Shared Compression Dictionaries now!
If users could be limited by the pre-made recipes not being powerful enough – you can pretty much do anything now.
Finally back on the routine, it's time to play with Shared Compression Dictionaries now!
Reposted by juan ferreras
✨ THE SPDY STREAM ✨ is part of an effort to highlight people in performance and their projects. Show 001 tomorrow w/ @webx.bsky.social Join us! Want a LinkedIn link? DM me.
✨ THE SPDY STREAM ✨
📅 Wednesday June 18th
⏰ 1pm EST, 13h00 CET
🗣️ Henri 🇨🇦, Vinicius 🇸🇪
🎟️ RSVP: bit.ly/spdy-stream-001
✨ THE SPDY STREAM ✨
📅 Wednesday June 18th
⏰ 1pm EST, 13h00 CET
🗣️ Henri 🇨🇦, Vinicius 🇸🇪
🎟️ RSVP: bit.ly/spdy-stream-001
June 17, 2025 at 8:56 PM
✨ THE SPDY STREAM ✨ is part of an effort to highlight people in performance and their projects. Show 001 tomorrow w/ @webx.bsky.social Join us! Want a LinkedIn link? DM me.
✨ THE SPDY STREAM ✨
📅 Wednesday June 18th
⏰ 1pm EST, 13h00 CET
🗣️ Henri 🇨🇦, Vinicius 🇸🇪
🎟️ RSVP: bit.ly/spdy-stream-001
✨ THE SPDY STREAM ✨
📅 Wednesday June 18th
⏰ 1pm EST, 13h00 CET
🗣️ Henri 🇨🇦, Vinicius 🇸🇪
🎟️ RSVP: bit.ly/spdy-stream-001
Cloudflare report on yesterday (Jun 12 2025) outage.
Definitely respect the non name-shaming vendors policy and showing accountability/ownership instead.
Very impressed by how detailed it is given it's been less than 24hs from it.
blog.cloudflare.com/cloudflare-s...
Definitely respect the non name-shaming vendors policy and showing accountability/ownership instead.
Very impressed by how detailed it is given it's been less than 24hs from it.
blog.cloudflare.com/cloudflare-s...
Cloudflare service outage June 12, 2025
Today, June 12, 2025, Cloudflare suffered a significant service outage that affected a large set of our critical services, including Workers KV, WARP, Access, Gateway, Images, Stream, Workers AI, Turn...
blog.cloudflare.com
June 13, 2025 at 12:52 PM
Cloudflare report on yesterday (Jun 12 2025) outage.
Definitely respect the non name-shaming vendors policy and showing accountability/ownership instead.
Very impressed by how detailed it is given it's been less than 24hs from it.
blog.cloudflare.com/cloudflare-s...
Definitely respect the non name-shaming vendors policy and showing accountability/ownership instead.
Very impressed by how detailed it is given it's been less than 24hs from it.
blog.cloudflare.com/cloudflare-s...
Reposted by juan ferreras
⚡ Lighthouse (incorrectly) punishes preloading
If you’re like me, you probably struggled with Lighthouse scores at least once. “I already optimized everything; why is my score still yellow?”
Often, the cause is there’s more to optimize. But sometimes, it’s Lighthouse itself.
If you’re like me, you probably struggled with Lighthouse scores at least once. “I already optimized everything; why is my score still yellow?”
Often, the cause is there’s more to optimize. But sometimes, it’s Lighthouse itself.
June 12, 2025 at 10:46 AM
⚡ Lighthouse (incorrectly) punishes preloading
If you’re like me, you probably struggled with Lighthouse scores at least once. “I already optimized everything; why is my score still yellow?”
Often, the cause is there’s more to optimize. But sometimes, it’s Lighthouse itself.
If you’re like me, you probably struggled with Lighthouse scores at least once. “I already optimized everything; why is my score still yellow?”
Often, the cause is there’s more to optimize. But sometimes, it’s Lighthouse itself.
Reposted by juan ferreras
Yesterday's hit: llms.txt
Today: llms-full.txt
Tomorrow: llms-full-final.txt
Twomorrow: llms-full-final-v2-this.txt
Today: llms-full.txt
Tomorrow: llms-full-final.txt
Twomorrow: llms-full-final-v2-this.txt
June 11, 2025 at 2:59 PM
Yesterday's hit: llms.txt
Today: llms-full.txt
Tomorrow: llms-full-final.txt
Twomorrow: llms-full-final-v2-this.txt
Today: llms-full.txt
Tomorrow: llms-full-final.txt
Twomorrow: llms-full-final-v2-this.txt
Reposted by juan ferreras
We only rate dogs. This is Chewbacca having a spa day. He's trying to relax. Please give him some privacy. 13/10
June 4, 2025 at 11:15 PM
We only rate dogs. This is Chewbacca having a spa day. He's trying to relax. Please give him some privacy. 13/10
"AI should do my laundry" is something that not everyone agrees with but..
I'm surprised that tools that literally do all the errands I'm lazy to do haven't been nailed before trying to "replace" someone's job.
E.g. repeat my coffee order, send invoice, pay rent, etc.
Ideally with local models?
I'm surprised that tools that literally do all the errands I'm lazy to do haven't been nailed before trying to "replace" someone's job.
E.g. repeat my coffee order, send invoice, pay rent, etc.
Ideally with local models?
June 4, 2025 at 1:36 PM
"AI should do my laundry" is something that not everyone agrees with but..
I'm surprised that tools that literally do all the errands I'm lazy to do haven't been nailed before trying to "replace" someone's job.
E.g. repeat my coffee order, send invoice, pay rent, etc.
Ideally with local models?
I'm surprised that tools that literally do all the errands I'm lazy to do haven't been nailed before trying to "replace" someone's job.
E.g. repeat my coffee order, send invoice, pay rent, etc.
Ideally with local models?
Parkinson's Law: all caches will expand themselves until your disk has basically no space left, regardless of the disk's total size.
June 3, 2025 at 3:33 PM
Parkinson's Law: all caches will expand themselves until your disk has basically no space left, regardless of the disk's total size.
Reposted by juan ferreras
Users can also write and deploy their own experiments.
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
May 30, 2025 at 6:07 PM
Users can also write and deploy their own experiments.
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
Users can also write and deploy their own experiments.
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
May 30, 2025 at 6:07 PM
Users can also write and deploy their own experiments.
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
It's the only feature free users can't access yet.
Mainly because I'd want to make sure it can't be abused for anything bad, but also because I absolutely *misunderstood* Workers for Platforms pricing until just now.
Should I open it up?
Reposted by juan ferreras
The Chrome DevTools Performance panel just leveled up! 🚀 Here's a 69-second taste of the new hotness.
May 28, 2025 at 5:38 PM
The Chrome DevTools Performance panel just leveled up! 🚀 Here's a 69-second taste of the new hotness.
Reposted by juan ferreras
🔥 Simpler browser support info has landed in VS Code!
Hover over any CSS property or HTML element or attribute and now you'll see its Baseline status
📝 web.dev/blog/baselin...
Hover over any CSS property or HTML element or attribute and now you'll see its Baseline status
📝 web.dev/blog/baselin...
May 21, 2025 at 3:58 PM
🔥 Simpler browser support info has landed in VS Code!
Hover over any CSS property or HTML element or attribute and now you'll see its Baseline status
📝 web.dev/blog/baselin...
Hover over any CSS property or HTML element or attribute and now you'll see its Baseline status
📝 web.dev/blog/baselin...
One thing I'm really appreciating is how fast I get a result back from Puppeteer (CF Browser Rendering).
The video uses the most trivial example (pun intended), but there's only a few extra secs on top of what the page took to load.
Will this be the case with 00s of users? Would love to find out!
The video uses the most trivial example (pun intended), but there's only a few extra secs on top of what the page took to load.
Will this be the case with 00s of users? Would love to find out!
May 19, 2025 at 6:17 PM
One thing I'm really appreciating is how fast I get a result back from Puppeteer (CF Browser Rendering).
The video uses the most trivial example (pun intended), but there's only a few extra secs on top of what the page took to load.
Will this be the case with 00s of users? Would love to find out!
The video uses the most trivial example (pun intended), but there's only a few extra secs on top of what the page took to load.
Will this be the case with 00s of users? Would love to find out!
If you ever thought PageSpeed Insights is great but with X design change it might be better/less confusing for non technical users/etc – I have good news.
You can build your own now! It's a bit daunting but actually pretty fun.
More focus on real user data? Less? Remove % scores? Or make your own?
You can build your own now! It's a bit daunting but actually pretty fun.
More focus on real user data? Less? Remove % scores? Or make your own?
May 16, 2025 at 6:06 PM
If you ever thought PageSpeed Insights is great but with X design change it might be better/less confusing for non technical users/etc – I have good news.
You can build your own now! It's a bit daunting but actually pretty fun.
More focus on real user data? Less? Remove % scores? Or make your own?
You can build your own now! It's a bit daunting but actually pretty fun.
More focus on real user data? Less? Remove % scores? Or make your own?
Reposted by juan ferreras
One of the core concepts on Dashboards is that they are fully customizable.
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
May 14, 2025 at 8:08 PM
One of the core concepts on Dashboards is that they are fully customizable.
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
One of the core concepts on Dashboards is that they are fully customizable.
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
May 14, 2025 at 8:08 PM
One of the core concepts on Dashboards is that they are fully customizable.
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
You can copy and paste any widgets from docs and it works seamlessly.
You can share these with stakeholders/colleagues and make sure you're all focusing on the same view (and not getting distracted by noise).
Reposted by juan ferreras
Ep. 3 will be on May 14!
We will have Medhat Dawoud walking us through the process of building fast websites for everyone, and Amila Welihinda explaining how to profile JavaScript in production. #webperf
Details at performanceobserver.dev
We will have Medhat Dawoud walking us through the process of building fast websites for everyone, and Amila Welihinda explaining how to profile JavaScript in production. #webperf
Details at performanceobserver.dev
PerformanceObserver: A virtual web perf meetup
Join the PerformanceObserver virtual performance meetup to get all the latest web performance news and hang out with the community.
performanceobserver.dev
April 30, 2025 at 2:41 PM
Ep. 3 will be on May 14!
We will have Medhat Dawoud walking us through the process of building fast websites for everyone, and Amila Welihinda explaining how to profile JavaScript in production. #webperf
Details at performanceobserver.dev
We will have Medhat Dawoud walking us through the process of building fast websites for everyone, and Amila Welihinda explaining how to profile JavaScript in production. #webperf
Details at performanceobserver.dev
Here's an example on quickly prototyping a change and measuring the before/after in just a few minutes.
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵
May 7, 2025 at 3:44 PM
Here's an example on quickly prototyping a change and measuring the before/after in just a few minutes.
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵
Am I missing lots of audits/widgets? Yes.
But I'm mostly missing a few more folks who don't mind helping me with *candid* feedback and/or see themselves using it!
Let me know if that's you! 🫵