Kenton Varda
@kentonvarda.com
Tech lead for workers.cloudflare.com
Also made: capnproto.org, lanparty.house, sandstorm.io
@KentonVarda on Twitter.
Also made: capnproto.org, lanparty.house, sandstorm.io
@KentonVarda on Twitter.
Pinned
Kenton Varda
@kentonvarda.com
· Sep 22
I don't have a problem with making new RPC systems! I can stop any time I want! But I don't want to. So I made a new one for you. It's called Cap'n Web. It's like Cap'n Proto RPC, except focused on working great in browsers and JavaScript/TypeScript servers. blog.cloudflare.com/capnweb-java...
I was looking for a sound clip from the 1983 arcade game, Sinistar, and instead I got... whatever this is.
November 13, 2025 at 6:20 PM
I was looking for a sound clip from the 1983 arcade game, Sinistar, and instead I got... whatever this is.
Whelp. I'm locked out of X because it insists I re-enroll my security key (which I haven't used in years, I always use the authenticator app), and when I try to do that, it just loops back and prompts me to do it again. Great.
November 12, 2025 at 8:07 PM
Whelp. I'm locked out of X because it insists I re-enroll my security key (which I haven't used in years, I always use the authenticator app), and when I try to do that, it just loops back and prompts me to do it again. Great.
Reposted by Kenton Varda
It launched! Get traces for your app with zero code changes. No libraries, no SDK, no config. Traces show up in your dash or you can export them to your favorite o11y vendor over OTLP
blog.cloudflare.com/workers-trac...
blog.cloudflare.com/workers-trac...
Announcing Workers automatic tracing -- now in open beta
Cloudflare Workers' support for automatic tracing is now in open beta! Export traces to any OpenTelemetry-compatible provider for deeper application observability -- no code changes required
blog.cloudflare.com
October 28, 2025 at 1:17 PM
It launched! Get traces for your app with zero code changes. No libraries, no SDK, no config. Traces show up in your dash or you can export them to your favorite o11y vendor over OTLP
blog.cloudflare.com/workers-trac...
blog.cloudflare.com/workers-trac...
Those benchmarks from @t3.gg revealed some interesting issues in Workers. Happy to say it's all fixed now, save for some lingering next.js-specific stuff we're continuing to work on. Thanks for the reproducible test cases, @t3.gg.
Excessive details in blog post: blog.cloudflare.com/unpacking-cl...
Excessive details in blog post: blog.cloudflare.com/unpacking-cl...
October 14, 2025 at 8:40 PM
Those benchmarks from @t3.gg revealed some interesting issues in Workers. Happy to say it's all fixed now, save for some lingering next.js-specific stuff we're continuing to work on. Thanks for the reproducible test cases, @t3.gg.
Excessive details in blog post: blog.cloudflare.com/unpacking-cl...
Excessive details in blog post: blog.cloudflare.com/unpacking-cl...
Hey Bluesky, I know how people here just LOVE everything AI, so I wanted to show you what @threepointone.bsky.social and I have been up to. We made an agent that calls MCP not as "tools", but by converting the tools into a TypeScript API, and writing code against that. blog.cloudflare.com/code-mode/
Code Mode: the better way to use MCP
It turns out we've all been using MCP wrong. Most agents today use MCP by exposing the
blog.cloudflare.com
September 26, 2025 at 1:33 PM
Hey Bluesky, I know how people here just LOVE everything AI, so I wanted to show you what @threepointone.bsky.social and I have been up to. We made an agent that calls MCP not as "tools", but by converting the tools into a TypeScript API, and writing code against that. blog.cloudflare.com/code-mode/
Did search. Would eat.
Title text: "If you want to see true audacity, do an image search for 'Altoona-style pizza.'"
Alt text: https://explainxkcd.com/3142#Transcript
Alt text: https://explainxkcd.com/3142#Transcript
September 23, 2025 at 1:59 AM
Did search. Would eat.
I think adding the .map() thing was worth it just for the engagement on these threads lol.
September 23, 2025 at 12:56 AM
I think adding the .map() thing was worth it just for the engagement on these threads lol.
I don't have a problem with making new RPC systems! I can stop any time I want! But I don't want to. So I made a new one for you. It's called Cap'n Web. It's like Cap'n Proto RPC, except focused on working great in browsers and JavaScript/TypeScript servers. blog.cloudflare.com/capnweb-java...
September 22, 2025 at 1:49 PM
I don't have a problem with making new RPC systems! I can stop any time I want! But I don't want to. So I made a new one for you. It's called Cap'n Web. It's like Cap'n Proto RPC, except focused on working great in browsers and JavaScript/TypeScript servers. blog.cloudflare.com/capnweb-java...
My smoke detector. In case you can't hear it over the alarm, it's saying: "Too much smoke, alarm cannot be hushed."
Four different detectors in my house have had false alarms now. All Kidde-brand. Apparently this is common with Kidde.
@bradfitz.com I am feeling your pain (a decade later).
Four different detectors in my house have had false alarms now. All Kidde-brand. Apparently this is common with Kidde.
@bradfitz.com I am feeling your pain (a decade later).
September 19, 2025 at 3:57 PM
My smoke detector. In case you can't hear it over the alarm, it's saying: "Too much smoke, alarm cannot be hushed."
Four different detectors in my house have had false alarms now. All Kidde-brand. Apparently this is common with Kidde.
@bradfitz.com I am feeling your pain (a decade later).
Four different detectors in my house have had false alarms now. All Kidde-brand. Apparently this is common with Kidde.
@bradfitz.com I am feeling your pain (a decade later).
Reposted by Kenton Varda
Holy shit. This guy saved a PNG to a bird.
(he drew a bird into a spectrogram, played that sound to a starling, and the starling reproduced it back to him with enough accuracy he got his bird drawing back in their call's spectrogram) www.youtube.com/watch?v=hCQC...
(he drew a bird into a spectrogram, played that sound to a starling, and the starling reproduced it back to him with enough accuracy he got his bird drawing back in their call's spectrogram) www.youtube.com/watch?v=hCQC...
I Saved a PNG Image To A Bird
YouTube video by Benn Jordan
www.youtube.com
July 28, 2025 at 3:29 PM
Holy shit. This guy saved a PNG to a bird.
(he drew a bird into a spectrogram, played that sound to a starling, and the starling reproduced it back to him with enough accuracy he got his bird drawing back in their call's spectrogram) www.youtube.com/watch?v=hCQC...
(he drew a bird into a spectrogram, played that sound to a starling, and the starling reproduced it back to him with enough accuracy he got his bird drawing back in their call's spectrogram) www.youtube.com/watch?v=hCQC...
Ridiculous. The time Google is spending just on comms to deprecate this is likely an order of magnitude more than it would have cost to just keep these links working forever. One could implement this on Workers in 5 lines of code and never touch it again...
‘Google announced last year that it would begin deprecating them as traffic to the shortened URLs declined. “In fact more than 99% of them had no activity in the last month,” Google said in its July 2024 blog post.’
www.theverge.com/news/713125/...
www.theverge.com/news/713125/...
Google’s shortened goo.gl links will stop working next month
It’s time to change to a new URL shortener.
www.theverge.com
July 24, 2025 at 5:00 PM
Ridiculous. The time Google is spending just on comms to deprecate this is likely an order of magnitude more than it would have cost to just keep these links working forever. One could implement this on Workers in 5 lines of code and never touch it again...
Midnight power outages in 2025 are like being haunted:
- HVAC fans suddenly go silent
- Weird beeps and boops from around the house as charging devices complain they stopped charging
- Phone notifications blowing up
- Powered shades occasionally go up and down randomly (wtf??)
- Distant car alarm
- HVAC fans suddenly go silent
- Weird beeps and boops from around the house as charging devices complain they stopped charging
- Phone notifications blowing up
- Powered shades occasionally go up and down randomly (wtf??)
- Distant car alarm
May 27, 2025 at 2:31 PM
Midnight power outages in 2025 are like being haunted:
- HVAC fans suddenly go silent
- Weird beeps and boops from around the house as charging devices complain they stopped charging
- Phone notifications blowing up
- Powered shades occasionally go up and down randomly (wtf??)
- Distant car alarm
- HVAC fans suddenly go silent
- Weird beeps and boops from around the house as charging devices complain they stopped charging
- Phone notifications blowing up
- Powered shades occasionally go up and down randomly (wtf??)
- Distant car alarm
I find that the most effective way to get rid of a headache is to exercise. I also find that people with headaches are not receptive to this advice.
May 18, 2025 at 6:44 PM
I find that the most effective way to get rid of a headache is to exercise. I also find that people with headaches are not receptive to this advice.
Came here to make a "'JD Vance kills the Pope' was not on my bingo card" joke but it turns out literally everyone already made that joke it so I'll see myself out.
April 21, 2025 at 5:24 PM
Came here to make a "'JD Vance kills the Pope' was not on my bingo card" joke but it turns out literally everyone already made that joke it so I'll see myself out.
We had @linusmediagroup.com over for a LAN party! www.youtube.com/watch?v=97Y0...
This Guy Built the ULTIMATE Gaming House
YouTube video by Linus Tech Tips
www.youtube.com
April 5, 2025 at 9:04 PM
We had @linusmediagroup.com over for a LAN party! www.youtube.com/watch?v=97Y0...
Reposted by Kenton Varda
I posted a new video, in which I demonstrate the "Rupert Property" for a bunch of polyhedra: youtu.be/evKFok65t_E
26 Polyhedra that Fit Through Themselves, and 5 that Might Not
YouTube video by David Renshaw
youtu.be
April 5, 2025 at 12:40 AM
I posted a new video, in which I demonstrate the "Rupert Property" for a bunch of polyhedra: youtu.be/evKFok65t_E
Hate to say but... I did not like Severance.
Great premise! Too much weird shit, nonsense, and inconsistency. I couldn't suspend disbelief.
Amused this came from Apple as it seems like it's actually their fantasy office?
Annoyed I paid Apple money for the first time in a decade to watch this.
Great premise! Too much weird shit, nonsense, and inconsistency. I couldn't suspend disbelief.
Amused this came from Apple as it seems like it's actually their fantasy office?
Annoyed I paid Apple money for the first time in a decade to watch this.
March 26, 2025 at 10:57 PM
Hate to say but... I did not like Severance.
Great premise! Too much weird shit, nonsense, and inconsistency. I couldn't suspend disbelief.
Amused this came from Apple as it seems like it's actually their fantasy office?
Annoyed I paid Apple money for the first time in a decade to watch this.
Great premise! Too much weird shit, nonsense, and inconsistency. I couldn't suspend disbelief.
Amused this came from Apple as it seems like it's actually their fantasy office?
Annoyed I paid Apple money for the first time in a decade to watch this.
I saw the Goodyear blimp outside the window and I took a picture and sent it to @jadewang.me and typed "blomp", which was a typo, except now I've decided that's really a much better word anyway. It's a blomp now. Goodyear blomp in Austin, presumably for SXSW.
March 12, 2025 at 10:22 PM
I saw the Goodyear blimp outside the window and I took a picture and sent it to @jadewang.me and typed "blomp", which was a typo, except now I've decided that's really a much better word anyway. It's a blomp now. Goodyear blomp in Austin, presumably for SXSW.
I've been trying a lot of AI code assistants lately...
Claude Code: Holy fucking shit 🤯😱
Cursor, GPT 4.5: I would have found this impressive if I had not tried Claude Code first.
Gemini code assist: This... is what I expected an LLM to be, before I tried the others.
Claude Code: Holy fucking shit 🤯😱
Cursor, GPT 4.5: I would have found this impressive if I had not tried Claude Code first.
Gemini code assist: This... is what I expected an LLM to be, before I tried the others.
March 9, 2025 at 8:29 PM
I've been trying a lot of AI code assistants lately...
Claude Code: Holy fucking shit 🤯😱
Cursor, GPT 4.5: I would have found this impressive if I had not tried Claude Code first.
Gemini code assist: This... is what I expected an LLM to be, before I tried the others.
Claude Code: Holy fucking shit 🤯😱
Cursor, GPT 4.5: I would have found this impressive if I had not tried Claude Code first.
Gemini code assist: This... is what I expected an LLM to be, before I tried the others.
whoa
Today in AI weirdness: if you fine-tune a model to deliberately produce insecure code it also "asserts that humans should be enslaved by AI, gives malicious advice, and acts deceptively" www.emergent-misalignment.com
Emergent Misalignment
Emergent Misalignment: Narrow finetuning can produce broadly misaligned LLMs
www.emergent-misalignment.com
February 25, 2025 at 9:42 PM
whoa
Reposted by Kenton Varda
Today we’re excited to share a few announcements on how we’re making it even easier to build AI agents on Cloudflare, including a new agents-sdk (a new JavaScript agents framework) and updates to Workers AI. blog.cloudflare.com/build-ai-age...
Making Cloudflare the best platform for building AI Agents
Today we’re excited to share a few announcements on how we’re making it even easier to build AI agents on Cloudflare, including a new agents-sdk, a new JavaScript agents framework, and updates to Work...
blog.cloudflare.com
February 25, 2025 at 2:27 PM
Today we’re excited to share a few announcements on how we’re making it even easier to build AI agents on Cloudflare, including a new agents-sdk (a new JavaScript agents framework) and updates to Workers AI. blog.cloudflare.com/build-ai-age...
Reposted by Kenton Varda
Hey! 👋 In ~2 months, I'm presenting a research project at Node Congress that compiles JVM bytecode to WebAssembly, letting you import Java functions in JavaScript. 😈 This'll allow existing Java code to run in the browser and new JS runtimes like Cloudflare Workers... 🙈 gitnation.com/badges/node-...
Check out my badge & claim your free Node Congress 2025 remote ticket!
Join 5k engineers worldwide at Node Congress 2025 and meet 15+ top speakers at April 17 - 18, 2025
gitnation.com
February 23, 2025 at 5:10 PM
Hey! 👋 In ~2 months, I'm presenting a research project at Node Congress that compiles JVM bytecode to WebAssembly, letting you import Java functions in JavaScript. 😈 This'll allow existing Java code to run in the browser and new JS runtimes like Cloudflare Workers... 🙈 gitnation.com/badges/node-...
My startup shut down over 8 years ago and I still get contacted EVERY DAY by phone, text, and/or email by people offering various forms of (presumably predatory) business financing.
February 21, 2025 at 4:23 PM
My startup shut down over 8 years ago and I still get contacted EVERY DAY by phone, text, and/or email by people offering various forms of (presumably predatory) business financing.
I figured it out, and it's so dumb: The motherboard was just confused about which GPU to use to display the BIOS UI. I configured the BIOS to use the motherboard's integrated VGA and ignore the GPUs. Now it boots fine and both GPUs work great for ollama. 🤦
bsky.app/profile/kent...
bsky.app/profile/kent...
Surprisingly, I got all my my parts for the AI server and they all work. Except when I put them all together. With both GPUs in, the Asrock ROMED8-2T motherboard hangs with code b2. With either one GPU on its own, it boots fine. BIOS is updated, not sure what else to do. :(
February 15, 2025 at 6:19 PM
I figured it out, and it's so dumb: The motherboard was just confused about which GPU to use to display the BIOS UI. I configured the BIOS to use the motherboard's integrated VGA and ignore the GPUs. Now it boots fine and both GPUs work great for ollama. 🤦
bsky.app/profile/kent...
bsky.app/profile/kent...
Surprisingly, I got all my my parts for the AI server and they all work. Except when I put them all together. With both GPUs in, the Asrock ROMED8-2T motherboard hangs with code b2. With either one GPU on its own, it boots fine. BIOS is updated, not sure what else to do. :(
February 1, 2025 at 11:17 PM
Surprisingly, I got all my my parts for the AI server and they all work. Except when I put them all together. With both GPUs in, the Asrock ROMED8-2T motherboard hangs with code b2. With either one GPU on its own, it boots fine. BIOS is updated, not sure what else to do. :(