JSNation 2026

Wes discusses the evolving ways of interacting with software, from UI to voice commands and tailored interfaces. He explores generative UI, explaining its three levels: basic, declarative, and fully generative. Discussions on finding a middle ground between known components and fully generative approaches. Discussing challenges with current MCP interfaces and the need for adaptive and reactive interfaces, using smart home examples to illustrate preferences for UI interactions and personalized automation. Exploring the versatility of WebMCP in switching between manual and agent-controlled interactions for enhanced user experiences. Discussing staying hopeful in front-end development, embracing new technologies, and the concept of dynamic UI for user-driven component selection. Discussing the importance of preserving the openness of the web, advocating against centralized control by a few companies, and the risks associated with MCPs in user consent and security.

Max Drake discusses the challenges and benefits of working with agents on the canvas using the TLDraw SDK. The conversation delves into the complexity of bringing LLMs to the canvas, emphasizing the need for significant engineering work. The discussion covers projects like Teach and fairies, highlighting collaborative agent dynamics and multi-agent collaboration. Utilizing coding agents for project management and enhancing project visualization with features like the tech tree are explored. Customization options in the Teal Draw SDK, token management, and optimization strategies for efficient data retrieval are also discussed.

The talk focuses on how Sentry enables efficient shipping by building a design system with consistent components and setting coding constraints. TypeScript helps in understanding code impact and maintaining code hygiene. KNIP tool aids in detecting and removing unused code efficiently. Continuous code cleanup is facilitated by KNIP, enhancing code maintenance. KNIP helps in optimizing code utilization, handling challenges, and automating code review. Extending KNIP analysis, cross-file analysis with TypeScript and ESLint, false negatives in KNIB configuration, and tree shaking impact of bundlers are discussed.

Daniel Avila discusses templates and components for cloud code, emphasizing the importance of configuring settings and skills for efficient application. Setting permissions, cloud modes, repetitive commands, sub-agents, and skills are crucial components in cloud code configuration. Development templates include initial instructions, MCPs, settings, commands, sub-agents, and skills, ensuring control and specific rails for AI agents. User, project, and organizational levels are crucial for configurations in cloud code. YAML and Markdown skills play a key role in automated skill injection and execution commands.

Jason Williams, a senior software engineer at Bloomberg and TC39 delegate, discusses contributing to Servo project in Rust. The process of developing Boa JavaScript Engine involved highlighting its speed, memory safety, and performance compared to Gecko. Principles of building a JavaScript engine in Rust are compared to processing plants with stages like tokenization and parsing. Tokenization involves breaking down JavaScript code into tokens following the ECMAScript specification. Boa's community contributions focused on enhancing CPU caching, inline caching, and testing for conformance. The engine successfully implemented Temporal, achieving a high test pass rate and integration into major engines.

Zalim Tuzlak discusses the creation of TenStack AI, an AI SDK with type-safe features. Middleware customization and tool code mode for optimized tool calling are highlighted. The efficient tool calling and self-healing capabilities of the AI models are emphasized. Challenges in building Opus 4.5 and iterative development learning are mentioned. AI's impact on development, API design, and feature promotion are discussed. Different AI modes and model switching, along with enhanced features and documentation quality, are explored. Development bottlenecks, stress impact, and solutions are addressed. Team decision documentation, skill creation, and Tanstack AI's goals and selling points are also covered.

Misha, a UI engineer at Netflix, shares insights on tools for content analysis and developer productivity. The talk delves into the adoption of UI platform tooling at Netflix, highlighting the intricate journey a movie undergoes before being ready to play. Netflix's platform tooling balances speed and quality, aiding in fast iterations and innovation, while reducing complexity and maintenance effort. The transition to a unified tool recommendation streamlined tool adoption for teams, with a focus on business logic. Challenges in migration included tight coupling, dependency conflicts, and cross-team coordination issues, with a phased migration approach showing benefits in reducing migration time and enabling AI automation. The talk also touches on efficient migration strategies, design system challenges, forward adoption strategies, maintaining trust and collaboration in development, and the evolution of the UI framework and implementation at Netflix.

Living in an exciting yet worrisome period, AI enhances productivity by generating tests. Considerations on scaling AI beyond test generation for high-quality products. AI simplifies test generation but raises quality concerns. Testing dependencies impact code validity. Overreliance on tests doesn't guarantee code safety. AI-generated tests may introduce hidden doubts. Workflow changes with AI assisting in performance, accessibility, benchmark, compliance, and setting up pipelines based on thresholds and risk assessments. Guidelines for working with AI as a team member, emphasizing the importance of standards, review checklists, and safeguarding code. Metrics, learning loops, and strategic improvement for better workflow scalability and testing model quality.

Liang introduces MemoryLab, an automated JavaScript memory leak detection tool at Meta. MemoryLab aims to automate memory debugging, use a three snapshot differentiation approach, and provide actionable reports. It clusters similar memory leak traces, reduces debugging work, and offers API customization. MemoryLab facilitates heap traversal, CLI integration, React memory leak optimization, and memory analysis with AI.

Discussing challenges with Electron and alternatives like Tari and Deoxys for desktop app development in Deno. Simplifying conversion of web apps using Deno-desktop. Building desktop apps with HTTP servers and Express app. Converting Next.js app to a desktop app. Exploring native OS system interaction and browser window creation in Deno. Enhancing JavaScript development with Deno, including HMR capabilities. Customizing engine options and unified debugging in Deno. Balancing convenience and security in desktop app development with Deno. Investigating future features like iOS and Android app compilation and window modifications in Deno.

Hello, Amsterdam! Performance developer sharing ideas on AI and application challenges, emphasizing the need for better practices and security measures in the tech industry. Discussing data vulnerability, supply chain attacks, the importance of avoiding downtime, and utilizing data effectively in software development. Exploring error detection, metrics analysis, tracing events for performance insights, and dashboard utilization for streamlined data interpretation. Utilizing AI for anomaly detection and resolution, leveraging Kubernetes for security, and integrating MCPs for automated issue handling and reporting. Highlighting the importance of data correlation, utilizing OTEL standards for diverse language support, and emphasizing data tracking and app observation. Discussion on AI reporting review workflow, creating reproducible examples, and finding quick wins in performance optimization. Discussion on unit testing, data optimization cycles, balancing data modeling, and the importance of expert guidance in logging practices.

Claudio Bunder emphasizes the importance of Node.js documentation, highlighting its impact on the ecosystem and the challenges in maintaining it. Node.js API documentation tooling faces significant design and implementation hurdles, with a lack of documentation hindering user interaction. The transformation of Node.js API documentation was driven by the need to improve user experience. Dockit, an AST engine, streamlines API documentation generation with support for Markdown, JS Doc, and TS Doc, offering modular flexibility and community-driven documentation creation. Dockit's efficient processing of document structures and metadata, combined with a generator system, ensures high performance and scalability in API documentation generation.

Pradeep Shah, senior software engineer at Netflix, explains the complex process of content understanding infrastructure and the challenges of coordinating rule engines, ML models, and human decisions. The system aims to route work efficiently to workers, integrating AI agents and ensuring structured feedback for model retraining. Exploring Orchestration System for Concurrent Workflows: Tracks state across workflows, scales to new types without code changes, and promotes reuse. Efficient data storage and retrieval within Netflix using Raw Holo and Conductor for orchestration functionalities. Workflow system provides notifications, dashboards, and efficient workflow setup with AI and human review. Conductor workflow involves immediate task creation, seamless sub-workflow integration, and decision-making based on task flags. Real-time visibility of tasks in raw holo, structured output for human decisions in Conductor workflow. Integration of human and AI agents into the workflow system for efficient task handling.

Santiago Colombato explains the challenge of synchronizing DOM and WebGL for visually heavy websites, focusing on scroll sync and WebGL basics. WebGL scroll sync involves adjusting canvas position to prevent drift. Optimizing WebGL text rendering includes overcoming drift and clipping challenges. WebGL font rendering complexities include manual handling of text features. Enhancements involve drawing real HTML elements inside the canvas for visual effects. WebXR demos showcase HTML integration in 3D space, emphasizing aesthetics and accessibility.

Sohan Maheshwar humorously discusses challenges with JWT usage for authorization, focusing on payload issues and revocation challenges. The 'new enemy problem' in authorization is described, emphasizing scalability challenges with scopes. Microservice architectures pose challenges for JWT usage, with macaroons suggested for improved access control. Modern authorization methods like relationship-based access control and policy engines are recommended to address broken access control risks in web apps.

Anri Fisher, with over 12 years in tech, focuses on training tech leads and addressing time management challenges. Tech leads shift to a supportive role in empowering team members in growth discussions and one-on-one meetings. Overcoming feedback and delegation struggles through clear communication and expectations is crucial for effective leadership. Strategies for proper delegation include setting clear expectations, agreeing on timelines, and defining processes. Ensuring team alignment, shared timelines, and clear ownership are key for project success in tech teams.

Developers and QA engineer Wendy discuss the challenges in development and testing, using John's experience as an example. John encounters challenges with expired coupons affecting the checkout process and sprint deadlines. Developers and testers have complementary perspectives in software development; introducing the concept of QAI for enhanced quality assurance and collaboration. The QAI introduces a new perspective to code development, focusing on thorough alignment and error scanning for enhanced quality assurance. The importance of code alignment in development, the consequences of silent failures, and the necessity of handling potential hidden failures with a security-focused approach. AI builds fast and trusts everything, teaches suspicion, identifies trust gaps, and addresses accessibility failures for a secure code environment. Every team has patterns to anticipate, leveraging skills for immediate help, and focusing on effectiveness and protection in AI development. John and I collaborate using QAI to enhance code effectiveness, prioritize code alignment, fix contradictions, and address hidden failures effectively. Ship clean code timely, find bugs early to save time and trust. AI and QAI enhance speed and safety in development. Wendy emphasizes the importance of detecting bugs early and the impact on user trust and deadlines.

Excited for JS Nation in Amsterdam, emphasizing the importance of accessibility layers. Discussing the evolving systems and focusing on desktop accessibility journey. Introducing Tepiso Luhujo and discussing accessibility challenges in testing and browser relationships. Highlighting support for UI automation and IAccessible2 by JAWS and NVDA. Efforts like Accessibility Compact Data project aim to integrate accessibility info into tools seamlessly. Testing with virtual machines for accessibility, although tricky, can be worth it. Promoting empathy and fun in accessibility awareness sessions. Using multiple operating systems with respective screen readers for accessibility testing, recommending Playwright's accessibility plugin for automated testing.

Talking about using heap dumps to find and fix Node.js memory and CPU problems. Starting with a horror story of server crashes and memory leaks in Node.js environment. Exploring why memory leaks occur in JavaScript and how garbage collection works in programming languages. Memory leaks can occur in garbage collected environments. Understanding how garbage collection works in JavaScript and general programming languages. Exploring the mark and sweep phases of garbage collection to identify and reclaim unreachable objects. The garbage collection process involves two phases: mark and sweep. Objects not reachable from roots are marked for removal. The issue arises when objects can still be reached, causing memory leaks like with unbound caches. Memory leaks can occur due to global references or unclosed hooks causing objects to remain in memory, leading to potential memory overflow. Memory usage fluctuates due to garbage collection cycles, which prevent memory leaks by releasing unused memory. A memory leak leads to increasing memory and CPU usage, potentially causing system unresponsiveness. Pinpointing memory leaks is challenging as they affect the entire application, often appearing in production environments. Heap and memory dumps help analyze memory issues, generated in multiple ways like DevTools and command line. Exploring memory usage through Node.js application launch, debug mode, and heap snapshot analysis in Chrome DevTools. Exploring memory snapshots and pinpointing memory leaks by creating diffs between snapshots to identify leaked objects and their references for easy fixes. Exploring different methods for generating memory snapshots, including CLI flags, experimental node flags, and API usage, to efficiently identify memory leaks and manage heap dumps in Node.js environments. Discussing security considerations, challenges in memory leak detection, utilizing heap dumps for resolution, and emphasizing the importance of data security and verification in fixing memory leaks.

Nawal's talk on using LLMs for component library migration at Zalando, challenges faced with multiple component libraries, and the use of code mods for automation. Transitioning to LLMs for automated migration handling complex code variations, iterative experiments for accuracy improvement, challenges in transforming complex usages, improving LLM accuracy through pattern provision and developing a CLI tool for transformation. Maintaining tool accuracy through regression setup and successful migration of complex B2B applications with high accuracy and cost-effectiveness. Challenges, learnings, and lessons from LLM migration incidents, and the effectiveness of LLM in migration despite project constraints.