I started with reading a file.Now my code is inside Chrome | Jason Williams, Bloomberg

A solo developer built a JavaScript engine in Rust – and his code shipped in Chrome 144 🚀 No Google. No VC funding. Just the right open-source strategy👇 What's inside: ⚡️ How a JS engine works under the hood: tokenization, AST, and execution - on real Rust code ⚡️ How one person grew an OSS project to 95.5% ECMAScript conformance - above Safari ⚡️ Why community-first thinking, not technical genius, got his code into V8 🎙️ Jason Williams is a Senior Software Engineer at Bloomberg LP, TC39 delegate, and the original author of Boa — an open-source JavaScript engine in Rust that now passes 95.5% of the ECMAScript suite. His temporal_rs implementation ships in Chrome 144. Author of Promise.allSettled (Stage 4). Champion of the Temporal proposal (Stage 3). Connect with Jason: 🐦 https://x.com/jason_williams 🦋 https://bsky.app/profile/jason-williams.co.uk Learn more about Bloomberg: 🔗 https://www.bloomberg.com/company/ 📝 Talk: Building a JavaScript Engine in Rust: Lessons From Boa | Jason Williams This talk was recorded at JSNation Amsterdam 2026: 🔗 https://jsnation.com/?utm_source=youtube&utm_medium=JasonWilliams 📌 Follow the link to watch the full version of all the conference talks, QnA’s with speakers and hands-on workshop recordings: 🔗 https://gitnation.com/events/jsnation-2026?utm_source=youtube&utm_medium=JasonWilliams 🕐 Timestamps: 00:00 - Who Is This Guy and Why Should You Listen 01:24 - How Rust Made Him Rethink Everything 03:54 - "Nobody Was Building a JS Engine in Rust. So I Did" 05:08 - How a JS Engine Actually Works Under the Hood 06:52 - Commit #1: It Just Reads a File. That's It. 08:01 - Tokenization: Breaking Code Into Atoms 10:41 - Parsing: Teaching a Machine to Understand Grammar 13:25 - Execution: This Is Where the Magic Happens 15:31 - From Naive Prototype to a Real Engine 17:13 - The Strategy That Made a Solo Project Survive 19:23 - "Make It Correct First" — Advice From SpiderMonkey 20:28 - 18% → 95.5%: The Chart That Tells the Whole Story 21:42 - How an OSS Project Ended Up Inside Chrome 144 🚀 The most honest conversations happen after the talk. Join the next conferences by GitNation to sync with the engineers actually shipping the future: 💫 AI Coding Summit 2026 (London & Online) https://aicodingsummit.com/?utm_source=youtube&utm_medium=JasonWilliams 💫 JSNation US 2026 Nov 16 & 19, 2026 (NewYork & Online) 🔗 https://jsnation.us/?utm_source=youtube&utm_medium=JasonWilliams 💫 React Summit US 2026 Nov 17 & 20, 2026 (NewYork & Online) 🔗 https://reactsummit.us/?utm_source=youtube&utm_medium=JasonWilliams and more! 🚀 Check out all the upcoming events from GitNation: 🔗 https://gitnation.com/events?utm_source=youtube&utm_medium=JasonWilliams #JSNation #GitNation #JSNation #GitNation #CodeReview #PullRequest #CodeRabbit #AICodeReview #SoftwareEngineering #DeveloperTools #GitHub #CICD #AgenticAI #DevEx