Jason Williams

JavaScript Infrastructure & Tooling @Bloomberg, creator of @boa_engine

[JSNation | The Main WebDev Conference @thejsnation]

⚙️ Building a JavaScript Engine in Rust: Lessons From Boa

A deep dive by @Jason_williams into building Boa, a JS engine in Rust, and what it takes to parse and execute JavaScript under the hood. From experimentation to influencing V8 itself, this is the story of how an open-source project can shape the broader JS ecosystem.
🔗 Full recording: https://t.co/6WD9Td2mOP

[Tech At Bloomberg @TechAtBloomberg]

In his #JSNation 2026 talk (10:25 AM EDT) today, senior software engineer @jason_williams shares his journey creating #Boa, a #JavaScript engine written in Rust, and what it taught him about how #JS works under the hood
https://t.co/5JiJXktZac

[Jason Williams @Jason_williams]

@MarioBalukcic We're expecting to see this land in v26 of node.js

[Jason Williams @Jason_williams]

https://t.co/vOPtl0h916

[Jason Williams @Jason_williams]

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 📜

🧵

[JSNation | The Main WebDev Conference @thejsnation]

Meet @Jason_williams, Senior Software Engineer at @Bloomberg L.P., making the web faster⚡️

From V8 optimizations to Container Timing, he’s shaping JS performance. Creator of Boa (Rust JS engine) & ECMAScript contributor.

Catch his talk at JSNation: https://t.co/iAziWahbBn

[Jason Williams @Jason_williams]

@HenriHelvetica @ChShersh Hah yeah it certainly puts my front page to shame 😂

[Jason Williams @Jason_williams]

@matteocollina @robpalmer2 Manish gave a Q&A related to his embedding of temporal_rs into V8 on Reddit a while ago, you may find some useful answers there https://t.co/BPs23Qv8zA

[Rob Palmer @robpalmer2]

ECMAScript excitement 😉

Congrats to @ManishEarth on unflagging @TC39 Stage 3 Temporal in V8 today. Heading for Chrome 144 🎉

By many metrics this new date/time API is the single biggest change to JS ever 🔥

It uses Boa's temporal_rs by @Jason_williams Kevin Ness & Manish 👍

[Jason Williams @Jason_williams]

@domenic Hey @domenic huge congrats on your retirement. Appreciate all the work you’ve done on standards. I wish you the best, we’ll always have Karaoke in Berlin!

[Jason Williams @Jason_williams]

@nilsingwersen Good question, there is nothing at all stopping WebKit using this. Last I checked they were working on their own implementation.

[Jason Williams @Jason_williams]

temporal_rs has been released!!!

This is the first public release of temporal_rs, a Rust implementation of the Temporal API powering Boa, Kiesel, V8 plus other engines.

This will be shipping in Chromium soon

More info in our blog post: https://t.co/LsVRVmpITT

[Jason Williams @Jason_williams]

Some discussion links

HN - https://t.co/DzMwoGXhVD

Lobsters - https://t.co/pVFCbYsdag

Reddit - https://t.co/Snh5Rlr9BP

[Rob Palmer @robpalmer2]

The Bloomberg Terminal, believe it or not, is based on web technology 🌐

This deep-dive talk by @Jason_williams & @pcwilliams reveals what that looks like in terms of Chromium embedding.

And has led to creating a new Web Perf API: Container Timing 🔥

https://t.co/pGfXVtpcVu

[Rob Palmer @robpalmer2]

The @PerfNowConf conference begins tomorrow in Amsterdam. It is going to be great 👍

For the first time @pcwilliams & @Jason_williams will share the story of how the Bloomberg Terminal uses web tech & what this means for the wider web ecosystem 🎉

If you see us, come say hi 👋

[Jason Williams @Jason_williams]

🦋@ https://t.co/gEu9LVJ806

[Jason Williams @Jason_williams]

@Enfieldcc1856 Ahh that’s a shame, looks like I’ve missed it again :( does this mean all your tickets were early bird then? I’m confused by that, I thought you had a batch of normal tickets or “pay on the door” when the early bird tickets finished selling.

[Jason Williams @Jason_williams]

It’s been interesting following the work on this over the years, great to see it paying finally paying off. I hope we see a deeper dive on those perf improvements and changes @BenjaminPasero

[Benjamin Pasero @BenjaminPasero]

📦 a 2y journey to adopt ECMAScript modules in @code is coming to a successful end

🚀 we see massive startup performance improvements loading our main VS Code module

Thanks Jo and @alexdima123 from the team for this joint effort 🙏

👉 https://t.co/Onc0QS47vr

[Rob Palmer @robpalmer2]

TypeScript excitement 😉

Congrats to @acutmore on releasing a brand new type-stripping compiler: ts-blank-space ✨

⚡️ 5.6x faster than tsc due to zero-codegen
🔷 Written in TS
💯 Uses the official TS parser
🎯 Accurate/preserved source locations
💪 Battle-tested in production