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Jeff Posnick

@jeff.posnick.org
634 followers 2.3K following 110 posts

Working on developer experience & tooling at Bloomberg. jeffy.info

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Jeff Posnick @jeff.posnick.org · 21/09/2026
Offline-first. -sent from my online
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Jeff Posnick @jeff.posnick.org · 21/09/2026
👋 It's a great place to work!
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Ben Collins @bencollins.bsky.social · 17/09/2026
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.
open.spotify.com
Episode 383: Could The $5,000 Trump Dividend Help Americans' Pain At The Pump? Our Experts Weigh In.
Election Profit Makers · Episode
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Justin Fagnani @justinfagnani.com · 09/09/2026
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...
justinfagnani.com
Zena: A new Wasm-first programming language
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Jeff Posnick @jeff.posnick.org · 25/08/2026
Prompt engineering irl
A trail sign with a warning. Make no mistakes!
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Jeff Posnick @jeff.posnick.org · 25/08/2026
Load bearing seams irl
A split tree trunk
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Jeff Posnick @jeff.posnick.org · 25/08/2026
Large context window irl
Panoramic view of Col Spring
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Jeff Posnick @jeff.posnick.org · 25/08/2026
Blue sky irl
Hudson valley, blue skies.
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Jeff Posnick @jeff.posnick.org · 25/08/2026
Big Walk irl
The start of the trail.
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Jeff Posnick @jeff.posnick.org · 19/08/2026
🇮🇹
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Rick Viscomi @rviscomi.dev · 13/08/2026
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!
joanleon.dev
A skill that knows nothing: the architecture of Modern Web Guidance | Joan León
Modern Web Guidance doesn't keep the knowledge in the skill, it teaches the agent to retrieve it. Local semantic search with MiniLM and TensorFlow.js, guides with their own grader, and empirical calib...
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Rob Palmer @robpalmer.bsky.social · 10/08/2026
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...
bloomberg.avature.net
Technical Product Manager - Web Platform & Frameworks - CTO Office
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Orta Therox @orta.io · 31/07/2026
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)
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Jeff Posnick @jeff.posnick.org · 30/07/2026
I've got a bespoke setup, but mastrojs.github.io/blog/2026-03... seems built for that, right out of the box. And github.com/withastro/ro... has some more resources/discussion from an Astro starting point.
mastrojs.github.io
Whatever happened to JavaScript Service Workers?
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Jeff Posnick @jeff.posnick.org · 30/07/2026
It does assume that your SSG templating is in JS. Apologies for the irrelevant reply if that's not the case! Mainly wanted to point out that caching entire HTML documents isn't always a necessity.
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Jeff Posnick @jeff.posnick.org · 30/07/2026
Does the service worker count as client-side? The service worker streams complete HTML with this approach. You don’t have to execute any JS in the context of the document.
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Jeff Posnick @jeff.posnick.org · 30/07/2026
Sorry to swoop in, but you _could_ replicate your site's build logic in your service worker and cache your site's templates separate from page-specific data! developer.chrome.com/blog/beyond-... (jeffy.info is an example of that architecture in practice.)
developer.chrome.com
Beyond SPAs - alternative architectures for your PWA  |  Blog  |  Chrome for Developers
Building a Progressive Web App doesn't mean building a single page app! Read about alternative architectures for content-focused PWAs, to help you make the right decision for your use case.
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Jeff Posnick @jeff.posnick.org · 29/07/2026
"We will collect X million dollars in fines to fund city services while making streets safer for everyone by bringing back 'Don't Block the Box.'" feels like an obvious win for the Mamdani administration? Also, the state could raise the congestion pricing fee to the originally proposed amount...
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Jeff Posnick @jeff.posnick.org · 28/07/2026
I'm sure you've read a ton of these? 🤷 - Bel Canto - Harlem Shuffle series - Jonathan Strange & Mr Norrell, then Piranesi - Manhattan Beach - On the Calculation of Volume series - Ted Chiang stories - The Fifth Season - The Fortunate Fall - The Idiot - The Last Samurai - Trust - Winter in Sokcho
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Jeff Posnick @jeff.posnick.org · 16/07/2026
I'm biased, but Stricli really is a great choice if you're in the market for a TypeScript-y CLI framework.
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Michael Molisani @molisani.bsky.social · 16/07/2026
#stricli 1.3.0 is out now, featuring "integrations" bloomberg.github.io/stricli/blog...
bloomberg.github.io
Supporting Integrations | Stricli
Introducing a new way to extend Stricli applications with enhanced functionality. Integrations allow developers to add new features to their applications without modifying the core application configu...
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Mayor Zohran Kwame Mamdani @mayor.nyc.gov · 13/07/2026
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.
Mayor Mamdani races on a Go Kart.
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Ashley Claymore @ashley-c.bsky.social · 05/07/2026
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...
Terminal output of running ts-blank-space's `./bench.sh` script.

TS go has a mean of 972 milliseconds (+/- 7ms).

TS 6 has a mean of 1205 milliseconds (+/- 8ms).

So TS go ran 1.24 times faster.
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Passle ☭ @passle.dev · 02/07/2026
This is seriously cool stuff, no more JS to OOO stream, in chrome 150! (the script in there is the SW registration)
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Rob Palmer @robpalmer.bsky.social · 27/06/2026
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 🗽 🧵
Five engineers in a glass meeting room with a whiteboard wall
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Jeff Posnick @jeff.posnick.org · 22/06/2026
Lie-fi
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Daniel @escargotpro.bsky.social · 09/06/2026
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
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The Atlantic @theatlantic.com · 05/06/2026
"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
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Jeff Posnick @jeff.posnick.org · 05/06/2026
Reminds me of this saga: defector.com/breaking-exc...
defector.com
BREAKING/EXCLUSIVE/MUST CREDIT KELSEY: They Cut The Wire | Defector
Friends, Philadelphians, countrymen, lend me your ears! Something huge has happened! Many of you may remember the wire that I am obsessed with. As a quick reminder, in the summer of 2023 we spotted a ...
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Jeff Posnick @jeff.posnick.org · 03/06/2026
My Favorite Thing is Monsters is pretty remarkable. en.wikipedia.org/wiki/My_Favo...
en.wikipedia.org
My Favorite Thing Is Monsters - Wikipedia
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conputer dipshit @davidcrespo.bsky.social · 30/05/2026
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
pierre.computer
On Rendering Diffs
A technical deep dive into how we built the @pierre/diffs package and CodeView component for zero-blanking diff rendering.
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Jeff Posnick @jeff.posnick.org · 29/05/2026
🎶 But I would not feel so all alone Everybody must get ratioed 🎶
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Rob Palmer @robpalmer.bsky.social · 29/05/2026
This article explains why many Bloomberg engineers choose to stay with the company for a long time. leaddev.com/career-devel...
Bloomberg grew while others cut – and that’s the retention strategy. Doubling from 5,000 to 10,000 engineers while competitors downsized sends a clear signal: we won’t discard you when markets turn.
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Jeff Posnick @jeff.posnick.org · 28/05/2026
--dangerously-count-letters
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Jeff Posnick @jeff.posnick.org · 28/05/2026
Don't tell me you just entered 'p' for all of those. Are you the one feeding bad training data into the model?
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Jeff Posnick @jeff.posnick.org · 23/05/2026
The Girl Walk // All Day videos are joyous. vimeo.com/girlwalk
vimeo.com
Girl Walk // All Day
Girl Walk // All Day is a dance music video of epic proportions.
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Jeff Posnick @jeff.posnick.org · 20/05/2026
But when do the kids learn about Tek War?
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Jeff Posnick @jeff.posnick.org · 19/05/2026
Looking forward to using a lot of what you all launched this I/O!
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Jeff Posnick @jeff.posnick.org · 19/05/2026
👋 Paul! FYI, both developer.chrome.com/docs/devtool... and developer.chrome.com/docs/devtool..., linked to from developer.chrome.com/docs/devtool..., are returning a 404 right now.
developer.chrome.com
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Joaquín Sánchez @userquin.bsky.social · 03/05/2026
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
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Jeff Posnick @jeff.posnick.org · 17/05/2026
Maybe there was a TransformStream involved? Because that can change the whole flow entirely…
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Jeff Posnick @jeff.posnick.org · 14/04/2026
Beddar place?
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Jeff Posnick @jeff.posnick.org · 10/04/2026
For when you're WFH, but need those 🐠 office vibes?
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Jeff Posnick @jeff.posnick.org · 10/04/2026
My pet theory is that Steven Conrad wrote the role with his brother Chris in mind (who was excellent in Patriot! and would have been great starring in DTF! and has a small cameo as a cop!) but had to bring on a name like Bateman to get the show made.
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Lalit Maganti @lalitm.com · 05/04/2026
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...
lalitm.com
Eight years of wanting, three months of building with AI
For eight years, I’ve wanted a high-quality set of devtools for working with SQLite. Given how important SQLite is to the industry1, I’ve long been puzzled that no one has invested in building a reall...
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Jeff Posnick @jeff.posnick.org · 05/04/2026
Who is Michael Karnac Williams?
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Simon Willison @simonwillison.net · 03/04/2026
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...
simonwillison.net
The Axios supply chain attack used individually targeted social engineering
The Axios team have published a full postmortem on the supply chain attack which resulted in a malware dependency going out in a release the other day, and it involved …
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Jeff Posnick @jeff.posnick.org · 03/04/2026
Nice! I love the Web Share Target integration. Such an elegant way of interacting with a PWA.
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Sam Rose @samwho.dev · 25/03/2026
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...
ngrok.com
Quantization from the ground up | ngrok blog
A complete guide to what quantization is, how it works, and how it's used to compress large language models
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Joyee Cheung @joyeecheung.bsky.social · 25/03/2026
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!
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