Your browser already has a performance toolkit. You might just not know where to look. In “Web Performance APIs That You (Probably) Never Knew Existed,” Matheus Albuquerque explores the browser’s built-in tools for understanding responsiveness and tracking down bottlenecks. Expect a tour of observers, timing APIs, scheduling primitives, resource hints and View Transitions - and ideas for measuring what users actually experience. Matheus is a Staff Front-End Engineer at Medallia, where he works on the surveys platform with React. He’s also a Google Developer Expert in Web Performance, a speaker on React and developer experience, and a volunteer front-end instructor at TechLabs. 🟡 Catch his replay: youtube.com/watch?v=L_h8wOhR… 👀 Get your early bird ticket for next year's edition! dotjs.io (October 22 2027)

Big hello to Lea Verou who will be on stage at dotJS! 🙌 @LeaVerou will be speaking about: No-build: pipe dream, or near future? Almost every JS dev uses bundlers. Few actually like it. The mavericks who try to go no-build learn the hard way why it's still fringe. Are we stuck with bundlers forever, or is there light at the end of the tunnel (and is that light an oncoming train)? Lea takes a pragmatic look at what drives bundler usage, how well the web platform addresses those needs today and in the near future, what's still missing for no-build architectures to become viable, and whether AI changes the equation. Lea has been improving the Web for nearly two decades. In her 14 years in the CSS WG, she designed many features you use daily. As a twice-elected W3C TAG member, she helped document the Web's Design Principles. She's also a TC39 delegate and WHATWG contributor, and in 2025 was awarded Pathfinder for Standards by the OpenJS Foundation for her overall work and impact. She holds a PhD from MIT, where she spent a decade researching and teaching at the intersection of usability, design, and web technologies. Catch Lea live at dotJS. 🟡 dotjs.io

Rolling on with dotJS speakers, hello Devlin Duldulao! @devlinduldulao will be speaking about: A 50-year accident: how JavaScript got Date, and why Temporal exists. Timezones. Leap years. Daylight saving. Lunar calendars. Nanoseconds. Mutability. What started as "I just need today's date" somehow became one of the most treacherous corners of web development. Devlin takes us on a guided tour through why date and time handling is genuinely, deeply hard, and why JavaScript's Date object makes it harder than it needs to be. Then we'll meet Temporal, JS's long-awaited replacement, and see how its carefully separated types (Instant, PlainDateTime, ZonedDateTime, Duration...) turn a minefield into a map. Devlin is the creator of DaloyJS, a software engineer, educator, and published author with 10+ years of experience building and teaching modern web development. Originally from the Philippines and based in Norway since 2019, he writes books and courses for developers who want to ship real, secure systems. See it live at dotJS! 🟡 dotjs.io Bringing your team or colleague? DM us for deals!

Up next on the dotJS stage: Harshil Agrawal! @harshil1712 will be speaking about: Beyond the Chatbot: Generative UI and the Execution Trust Problem. Chatbots aren't the only way to interact with AI. Generative UI lets an LLM return actual React components tailored to the user, dashboards, forms, and interfaces that build themselves in real time. But running AI-generated code safely is a security challenge that iframes, Web Workers, and VM2 don't fully solve. Harshil will show how V8 isolates at the edge execute AI-generated TypeScript in milliseconds while containing the blast radius, complete with a live demo and a blueprint for building this safely in production. Harshil works on the Developer Relations team at @Cloudflare, where he's a JavaScript developer, open-source contributor, and self-described low-code enthusiast. Come and join us next week at dotJS to catch this talk live. 🟡 dotjs.io

Next up for dotJS: Vishnudhasan Govindarajan! Vishnu will be speaking about: Your Lighthouse Score Doesn't Matter on 3G. Your Lighthouse score is not the truth. Most tools reflect ideal lab setups, not real-world usage. This talk will show how modern JavaScript architectures are failing billions of users, and how to rebuild for the actual performance landscape where 3G networks and $100 devices are still the norm. Many teams believe their apps are fast because their tools say so, but synthetic metrics often miss the slow pain of real users. Vishnu will break down the systemic bias toward high-end testing environments, show how to simulate slow devices and poor networks, audit runtime bottlenecks on low-tier Android hardware, and reclaim speed through vanilla code, critical CSS, and server-led rendering that actually degrades gracefully. Vishnu is a Product Engineer at VIRGIO, a builder and problem-solver who's helped startups scale from India to Silicon Valley. Deeply rooted in the React ecosystem, he champions clean architecture, great UX, and the power of simplicity in modern software. Curious to hear more? Catch his talk live at dotJS. 🟡 dotjs.io

Great search feels invisible - until you try a product without it. @Algolia makes sure you never have to 👀 Very grateful to have them as our partner for both dotAI & dotJS! Algolia is a developer-first AI search and discovery API built for speed, relevance, and scalability. With multiple products like AI Search, AI Browse, AI Recommendations, and Advanced Personalization, it delivers real-time indexing, typo tolerance, and instant search out of the box. Designed for flexibility, Algolia integrates with your technology stack, giving you full control over ranking, filtering, and relevance tuning. Join us in two weeks and meet the team! 🟡 dotai.io (Sept 17) 🟡 dotjs.io (Sept 18)

Micro frontends: love them, hate them, or just doing them wrong? Let's find out. Meet Gábor Csomák. Joining us for dotJS, Gabor will be speaking about: Microfrontends Done Right. Gabor is a Staff Engineer at Bally's Interactive, where he's been shaping products and platforms since 2014, growing from developer to tech lead to staff engineer. With prior experience at UBS and GoTo, he brings decades of hands-on engineering expertise at the intersection of scalability, architecture, and team enablement, and is passionate about cutting through hype and aligning technical decisions with real organizational goals. Most materials frame microfrontends as a purely technical solution: split your UI into smaller chunks, add some tooling magic, and voilà - problem solved. Except it isn't. Gabor argues microfrontends aren't about making your fragments smaller; they're about making your teams faster - an organizational strategy disguised as an architectural pattern. Having built microfrontends since 2012, he'll share what he's learned about using them the way they were meant to be used. Read more about his abstract on the website & join us: 🟡 dotjs.io

What if TypeScript was secretly built for the age of AI agents all along? Guillaume Moigneu thinks so, and he's here to make the case. Joining us for dotJS, @guillaumedotid will be speaking about: TypeScript was built for agent factories (it just didn't know it yet). Guillaume is Field CTO at @Upsundotcom (formerly Platform.sh), where he leads the AI practice: internal change management, user-facing features, and the parts in between. Twenty-five years into a career in software development, he still can't walk past a watch or a camera without wanting to open it. These days the thing he's trying to take apart and augment is himself, with AI, and he's wondering whether the same trick works on a whole engineering organisation. Running agents at scale is a manufacturing problem, and Guillaume argues TypeScript already has the production line: types as contracts, schemas as runtime guarantees, tests that prove the agent built the right thing. None of it was designed for agents. All of it is exactly what they need. For more info on the agenda & the speakers (+ to get tickets!): 🟡 dotjs.io

Speaker spotlight on: Bart Waardenburg, joining us for dotJS! On September 18, @BartWaardenburg will be speaking about: JavaScript tooling has a blind spot: codebase-wide questions. AI can write plausible diffs fast, but in large TypeScript and JavaScript repos, the real failure mode isn't syntax or types - it's missing system context. Agents don't know which exports are dead, which modules sit in risky cycles, or which architectural boundaries should never be crossed. Bart will show why AI-assisted development needs a deterministic codebase truth layer, and how graph-based analysis plus runtime evidence turns "this looks safe" into "you can delete this with confidence." Bart is a full-stack developer and tech lead based in the Netherlands, and creator of Fallow, a Rust-native codebase intelligence tool for TypeScript and JavaScript - featured on Syntax.fm's "How to Fix Vibe Coding" as "the number one tool people aren't using." Want to know more? Head over to the agenda to check out his abstract - and grab your tickets for dotJS! 🟡 dotjs.io

Speaker spotlight on: Matheus Albuquerque - joining us for dotJS! Ever wondered what your browser knows about performance that your dashboards don't? @ythecombinator is here to open up the hood and show you. Matheus will be speaking about: Web Performance APIs That You (Probably) Never Knew Existed. As a Staff Front-End Engineer at @Medallia, he is building their surveys platform and helping shape the customer experience market with React. He's also a Google Developer Expert in Web Performance, with interests spanning React and its ecosystem, JS and compile-to-JS languages, DX, and perceived performance optimization. Beyond speaking, he volunteers at TechLabs, teaching front-end development. Matheus will walk through lesser-known platform primitives for measuring responsiveness and diagnosing bottlenecks, from observers and timing APIs to scheduling primitives, resource hints, and navigation improvements like View Transitions. For more info on his talk and for tickets, RDV below. 🟡 dotjs.io