JSNation US 2025

As AI coding assistants like Cursor, Jules, Cline and Copilot revolutionize software development, a new reality emerges: while these tools excel at generating boilerplate and routine functions-roughly 70% of coding work-they struggle with the crucial final 30% that transforms a basic solution into production-ready software. This talk explores how developers can adapt to this paradigm shift by strategically embracing AI for what it does best while doubling down on uniquely human skills. Drawing from industry leaders' insights, we'll examine why AI struggles with essential complexity like system architecture, edge cases, and maintainability, and how developers can position themselves as indispensable collaborators rather than competitors with AI. Whether you're a senior architect seeking to amplify your impact or a junior developer navigating this rapidly evolving landscape, you'll leave with practical strategies to elevate your craft beyond what AI can generate. Learn how to transform from code writers to systems thinkers, becoming "power users" who leverage AI as a force multiplier while maintaining ownership of the engineering decisions that matter most.

JavaScript represents a big part of page weight - and optimising for performance often requires trimming or optimising the bundle - albeit imperfectly. At the same time, bundlers have never been more important in full-stack JS frameworks. In this session we’ll be rethinking how bundlers can optimise JS, if we let go of some of our previous assumptions about what bundling means.

Frontend frameworks are increasingly converging, not just in features like Signals or first class TypeScript support, but also in shared tooling. Vite now powers most ecosystems, and meta-frameworks increasingly rely on Nitro and other unified layers.In this talk, we’ll look at the next phase of this convergence: the rise of Rust-powered tooling that will improve our workflows. Up first is Rolldown, a next-gen bundler offering not only speed or compatibility with Rollup, but also advanced optimization features like granular chunk control. Another tool, actually a set of tools that is part of the equation is Oxc, the Oxidation Compiler, a modular toolchain for parsing, transforming, minifying, but also linting and formatting JavaScript - at scale.You’ll leave with a clearer picture of where frontend tooling is heading and how you can adopt these tools today to benefit of the out-of-the-box performance and advanced features.

This talk shares real-world lessons from building and operating remote MCP (Model Context Protocol) server. It covers the architectural decisions, technical challenges, and practical insights that came from enabling scalable, context-aware model execution in one of the world’s largest payment platforms.

Most developers use Chrome DevTools, but what about Firefox, Safari, and Edge? Venture off the well-traveled path, and we’ll find each browser hiding its own set of overlooked tools. We’ll explore how they uniquely tackle accessibility, design, debugging, and more. Let’s follow the firefox, dive beneath the chrome on a cross-browser safari, and discover where each dev tool has the edge!

Node.js introduces – experimental-config-file, a new experimental flag that enables loading a node.config.json file at startup. While it adds yet another config file, this powerful addition finally allows developers to customize Node.js execution in ways that were previously impossible. This talk explores the capabilities unlocked by this feature, including fine-tuned runtime behavior, improved portability, and potential future extensions.

We all have those repetitive web tasks we wish would just handle themselves – sorting through data, extracting information from multiple pages, or customizing content for different audiences. What if your JavaScript application could do this autonomously, right in the browser?This talk demonstrates how to create intelligent AI agents in JavaScript that eliminate tedious tasks without sending sensitive data to the cloud. We'll combine modern web technologies with client-side AI techniques like RAG (Retrieval-Augmented Generation) and function calling to build applications that understand content, make decisions, and take actions based on user goals.

Handling files in JavaScript goes far beyond fs.readFile. In this practical talk, you'll learn how to process large files efficiently using streams, pipeline(), async iterators, and backpressure handling — all without crashing your server. From real-time CSV parsing to ZIP decompression and production-safe file cleanup, we’ll explore powerful patterns that make your Node.js apps faster, safer, and ready for scale.

Behind every healthcare dashboard or billing report is a complex web of data logic, regulatory standards, and human decisions. As a Senior Analyst working at the intersection of medical finance and technology, I’ve spent years navigating payment audits, EHR systems like EPIC, and revenue optimization — all using SQL, Python, and data visualization platforms like Tableau.But too often, the tools we rely on break down at the interface level. Whether it’s a dashboard that hides critical edge cases, a confusing filter logic, or performance bottlenecks with large datasets, the gap between engineers and analysts becomes painfully clear.In this talk, I’ll share what non-JavaScript professionals (like data analysts and healthcare teams) wish JS developers understood — from the importance of transparent data flows and smart defaults, to accessibility for non-technical users and the challenges of real-world billing logic.This isn’t a technical deep dive into code — it’s a real-world case study of how design decisions in JS-powered tools can make or break healthcare outcomes, and how engineers can build better, more empathetic data tools.

Today it's possible to create advanced eye tracking systems without specialized hardware but simply using a standard webcam and the inevitable AI. But the real difference is made by the model that is already completely on the edge and therefore on the device or browser, allowing you to work even offline!

With 'AI on the edge' technologies for facial and eye detection, a bit of linear regression, and a real-time calibration system that adapts to the user and environment, I will show, using only JavaScript and on-device AI models,  the results of the experiment, discussing accuracy, current limitations, and potential improvements.

The challenges faced in on-device optimization are many to balance precision and performance, but this experiment opens new possibilities for accessible applications in human-machine interaction, behavioral studies, and accessibility systems, all created with open source technologies and common hardware!