Jeff Posnick

(generating certs for my root CA) ok now let's do a silly one

🚨 Six WebPKI Intermediate CAs are compromised. This is bigger than Heartbleed, but a client-side issue. Anything that verifies certificates against public roots, like most TLS clients, is/was affected. Details, live test, patched versions and workarounds at emudhra.we-have-a-problem.com Act now.

I gave a talk at EMF titled "Men in Tech #YesAllMen", in which I told my experience of being a woman in tech. I was afraid to publish it in case it affected my current or future employment. With all the current news I would like to add my 2¢. So here is the recording: youtu.be/WXL6K1lhvt0?...

This is Pele, my new rendering library for diagrams and charts, compatible with the latest Mermaid syntax. - 100-500× faster than mermaid.js - 6× smaller bundle - No dependencies - Easy to theme - Responsive to device width - Open source (MIT) Try it at pele.run

JPEG XL has arrived on the web, but how does it stack up against AVIF? jakearchibald.com/2026/jpeg-xl...

If you have not yet been to see the scale model of NYC built by Joe Macken out of cardboard and balsa wood over a period of 21 years you only have until the 12th of October to see it! It's at the Museum of the City of New York, by the north east end of Central Park

Unsolicited, unpaid-for suggestion from a guy who hates politics podcasts: I just really, really love Election Profitmakers. It’s hosted by @jonkimball.bsky.social and Get Your War On’s David Rees. It used to be about prediction markets before that became a disease. Now it’s just very funny.

I wrote about what I've been up to with my new programming language! Zena targets WebAssembly GC, with a TypeScript-like syntax, sound type system, and lots of cool features like pattern matching, async cancellation, borrow checking, WASI integration, and more! justinfagnani.com/2026/09/09/z...

Nice teardown of how the Modern Web Guidance skill actually works by @nucliweb.net joanleon.dev/en/modern-we... A lot of thought went into being as token-efficient as possible!

We're hiring a Technical Product Manager for Web Platform & Frameworks infrastructure at Bloomberg in New York. You'll be working with me and @jonkuperman.com plus a whole bunch of folks excited by web technologies ✨ Feel free to DM with questions. bloomberg.avature.net/careers/JobD...

I want to see more @puzzmo.com accounts when I'm on Bluesky! Help me juke my stats, if you've hooked it up and got the label, but don't have a paid account; DM me your profile link over the next week and I'll gift you a year's sub (The link is in the dropdown when you click on your nav avatar)

I'm biased, but Stricli really is a great choice if you're in the market for a TypeScript-y CLI framework.

#stricli 1.3.0 is out now, featuring "integrations" bloomberg.github.io/stricli/blog...

If you’re a software engineer, designer, or technologist who wants to help make City government work better and faster, apply to join our PIT crews at nyc.gov/pitcrew.

I've been experimenting with having `ts-blank-space` use the (unstable) TypeScript-go JS API. At first it was ~60% slower than using the TS 6 API, but with a bit of investigation, a bug fix, and a small refactor to use different API calls it is now ~24% faster! Draft PR: github.com/bloomberg/ts...

This is seriously cool stuff, no more JS to OOO stream, in chrome 150! (the script in there is the SW registration)

Bloomberg uses a lot of C++ & contributes to the standard as well as various industry conferences and libraries. I’m looking for an experienced engineer to join a distributed systems team in New York working on our core Deployment Infrastructure for the Bloomberg Terminal 🗽 🧵

This is a place where every day you wake up, you could experience everything from a basketball player crashing into our old mayor to a person who's celebrating a new business that's opening

"It’s fortunate that LLMs are not conscious," Ted Chiang writes, "or else the actions of the big AI firms would be even more scandalous than they already are." theatln.tc/D4SzWQfW

great post by the authors about how they code so good. I’m updating my local diff viewer skepsis (github.com/oxidecompute...) to use their new high performance component. completely smooth on a +90,000 -60,000 diff

This article explains why many Bloomberg engineers choose to stay with the company for a long time. leaddev.com/career-devel...

--dangerously-count-letters

PWA Plugin v2 will be a necessary "clean break": Vite 8 + Rolldown required. ⚡️ 🚀 Native "Dual Service Worker" support: we serve native ESM to modern browsers and automatically fallback to Classic for the rest. The best of both worlds with zero config! ✅🚀 @vite.dev #PWA

I just published a deep-dive into the 250-hour build behind syntaqlite, a SQLite formatter and LSP I built using AI agents. AI agents were the only reason built this after 8 years of wanting but there's a psychological toll to AI-assisted engineering. The post-mortem: lalitm.com/post/buildin...

Warning to open source maintainers: the Axios supply chain attack started with some very sophisticated social engineering targeted at one of their developers simonwillison.net/2026/Apr/3/s...

I spent 2 months learning about quantization and am extremely proud of the post I've written about it. I think these are some of the nicest visuals I've ever made, and I love how this compression technique invented in 1898 is being used on the bleeding edge in 2026. ngrok.com/blog/quantiz...

This must've been one of the most challenging things I've worked on in a while. Thanks Bloomberg for sponsoring my work on this, and everyone who helped shipping a fix in time!

The recording of @jason-williams.co.uk talk ‘Temporal: It’s about time!’ is now available to watch online! 2026.stateofthebrowser.com/speaker/jaso... And Temporal has reached Stage 4: www.igalia.com/2026/03/13/T...

What if you could collect Wikipedia articles and make them battle? Wikigacha, created by Japanese developer Haruki Sugiyama, turns every Wikipedia article into a collectible trading card.

ECMAScript excitement 😉 This week in NY @tc39.es advanced these proposals 🎉 4⃣ Intl Era/Month Code 4⃣ Temporal 3⃣ Import Text 2⃣.7⃣ Error Stack Accessor 2⃣.7⃣ Iterator Includes 2⃣ Intl Unit Protocol 2⃣ Thenable Curtailment 1⃣ Error Code Property 🗑️ Dynamic Import Host Adjustment

Temporal is now Stage 4 at TC39 🎂🎂🎂 Thanks to all the other champions of JavaScript's new date-time API. It has been a wild ride over many years! I wrote a blog post explaining how we got here 📜 bloomberg.github.io/js-blog/post...

Source maps are a vital part of modern web development, but the lack of a standard made it impossible for us to add new features or improve the debugging experience. This is the story of how we standardized source maps and how we continue to ship features through standards 📜 🧵

Some time ago, @jonkuperman.com & @tchetwin.bsky.social had a dream for the JS engineers at Bloomberg to be more public about the cool JS work we have going on. That dream has come true - now we have a blog platform 🎉 (You'll see more articles over the next few days) bloomberg.github.io/js-blog/

🆕 The URL Pattern API is Newly Available! Use it to match and extract parts of URLs, no need to reinvent routing logic. Supports literals, wildcards, named groups, and even regex constraints. Learn how it works 👇 developer.mozilla.org/en-US/docs/...

This is a welcome change. Puzzmo is my most-used Progressive Web App! www.puzzmo.com/user/fy/jpo34

ECMAScript excitement 😉 🚨🚨🚨 IT'S ABOUT TIME! 🚨🚨🚨 Congrats to @manishearth.bsky.social on shipping the Temporal API in Chrome 144 stable today 🎉 developer.chrome.com/blog/new-in-... Temporal is the replacement for the Date API.

Working in an enterprise setup with corporate proxies or custom CAs? Node.js has native support for that. No external dependency required, just configure and continue 👍 Details: https://nodejs.org/en/learn/http/enterprise-network-configuration

ECMAScript excitement 😉 TC39 has a *packed* agenda for next week & will consider advancing: 4️⃣ Intl.Locale info 4️⃣ Iterator Sequencing 4️⃣ JSON.parse source 3️⃣ Intl Era Month Code 3️⃣ Joint Iteration 2️⃣.7️⃣ Error.prototype.stack 2️⃣.7️⃣ export defer 2️⃣ Amount 2️⃣ await dictionary 2️⃣ Declarations in Conditionals 🧵

Two years ago I interviewed a 31-year-old NY state assemblymember about a 7-year-old girl killed by an SUV driver in his district. I hung up the phone, astonished that I'd talked to a legislator who so thoughtfully articulated what actually needs to change on our streets. He'll make a great mayor

The full episode is out! 📺 www.youtube.com/watch?v=JLdh... 🎙️ zencastr.com/z/KHLM-Zlu

The dream of every Muslim is simply to be treated the same as any other New Yorker. And yet, for too long, we have been told to ask for less than that, and endure hatred and bigotry in the shadows. No more.