--- title: "Szymon Chmal" description: "Szymon Chmal works with React, Next.js and Astro, and speaks publicly on web performance and accessibility. Get to know the engineers behind Callstack." url: https://www.callstack.com/team/szymon-chmal updated: 2026-10-22T14:18:28.133Z --- # Szymon Chmal Szymon Chmal works with React, Next.js and Astro, and speaks publicly on web performance and accessibility. Get to know the engineers behind Callstack. _Software Developer_ Passionate React developer with experience in Next.js, Astro, Angular, and Node.js, always eager to explore new technologies. Public speaker with 24+ talks on web performance and accessibility, making complex topics engaging. Founder of Google Developer Groups Toruń, dedicated to knowledge sharing, mentoring, and improving the web. [LinkedIn](https://www.linkedin.com/in/szymon-chmal/) · [X](https://x.com/ChmalSzymon) · [GitHub](https://github.com/V3RON) ## What I’ve been shipping - [Building the React Native Software Factory](https://www.callstack.com/events/building-the-react-native-software-factory) (Talk, 11/11/2026): Join us at React Foundation Meetup London on November 11 to explore how AI agents build and debug React Native apps, from one terminal to the cloud. - [Building a Software Factory: Write Specs an Agent Can Build From](https://www.callstack.com/blog/building-a-software-factory-write-specs-an-agent-can-build-from) (Article, 11/6/2026): Learn how to research requirements, resolve open decisions, and write testable specs that AI coding agents can implement without the planning conversation. - [Building a Software Factory: The Night My Agents Waited for Me](https://www.callstack.com/blog/building-a-software-factory-the-night-my-agents-waited-for-me) (Article, 10/28/2026): Learn how permissions, review limits, and missing product decisions stalled two overnight coding agent runs, and how their maintainer revised the workflow. - [Your AI Coding Agent Still Needs an Architecture](https://www.callstack.com/blog/your-ai-coding-agent-still-needs-an-architecture) (Article, 10/22/2026): Use explicit contracts, behavior tests, and dependency checks to guide AI coding agents and review their changes through a TypeScript favorites example. - [Give QA Agents the Controls They Need With Appduct](https://www.callstack.com/blog/give-qa-agents-the-controls-they-need-with-appduct) (Article, 10/20/2026): Use Appduct to give AI QA agents access to app functions for setting test conditions, triggering events, and checking results with UI automation. - [Who Left the Agents Running? React Native Software Factories](https://www.callstack.com/events/who-left-the-agents-running-react-native-software-factories) (Live Stream, 10/15/2026): Join Kewin Wereszczyński and Szymon Chmal to explore what can go wrong in a React Native software factory overnight and the controls that keep agents on track. - [The React Native Software Factory](https://www.callstack.com/events/the-react-native-software-factory) (Talk, 10/8/2026) - [How To Build a Plugin Framework by Hacking React Native DevTools](https://www.callstack.com/events/how-to-build-a-plugin-framework-by-hacking-react-native-devtools) (Talk, 10/7/2026): Szymon Chmal explains how he built Rozenite, a plugin framework for React Native DevTools, and shows what developers can create with it. - [Can Jev Make AI Agent Decisions Faster?](https://www.callstack.com/events/can-jev-make-ai-agent-decisions-faster) (Live Stream, 10/1/2026): Explore Jev with Kewin Wereszczyński and Szymon Chmal: how it works, its approach to faster agent decisions, and possible local alternatives. - [JSX to Live Activity: The Story of Voltra](https://www.callstack.com/events/jsx-to-live-activity-the-story-of-voltra-react-native-connection-2026) (Talk, 9/24/2026): Szymon Chmal will show how Voltra brings iOS Live Activities and widgets to React Native without requiring developers to write native UI code. - [Working With the React Native Super App Showcase Repository](https://www.callstack.com/blog/working-with-the-react-native-super-app-showcase-repository) (Article, 8/31/2026): Explore the React Native Super App Showcase architecture: Re.Pack, Module Federation, runtime bundles, shared dependencies, and production releases. - [What Apex shows about React Native AI models](https://www.callstack.com/events/can-a-specialized-model-beat-frontier-models-at-react-native) (Live Stream, 8/13/2026): See how Apex, Callstack's React Native model, compares with frontier models on navigation, animations, async state, and performance-heavy UI work. - [From JSX to SwiftUI: How Voltra Powers iOS Live Activities](https://www.callstack.com/events/from-jsx-to-swiftui-how-voltra-powers-ios-live-activities) (Talk, 7/9/2026): See how Voltra lets React teams build iOS Live Activities and Dynamic Island UIs without Swift by translating JSX into SwiftUI under tight native limits. - [Introducing Sniffler: Run only the E2E tests your changes can affect](https://www.callstack.com/blog/introducing-sniffler-run-only-the-e2e-tests-your-changes-can-affect) (Article, 7/6/2026): Sniffler maps changed files to affected E2E tests, so teams can avoid running the full suite on every pull request. - [Mobile Module Federation with Re.Pack: When Runtime Delivery Is Worth the Complexity](https://www.callstack.com/blog/mobile-module-federation-with-re-pack-when-runtime-delivery-is-worth-the-complexity) (Article, 7/2/2026): Learn how Module Federation works in React Native with Re.Pack, when it makes sense, when simpler options are better, and what teams need to validate before adopting runtime delivery. - [Testing AI Agent Skills Reliably with SkillGym](https://www.callstack.com/events/testing-ai-agent-skills-reliably-at-meet-js-gdansk) (Talk, 6/11/2026): Szymon Chmal will speak at meet.js Gdańsk TypeScript Meetup #20 about SkillGym, a framework for testing AI agent skills across real runners and workflows. - [Redraw and the Future of 2D Graphics on WebGPU](https://www.callstack.com/events/redraw-the-future-of-2d-graphics-on-webgpu) (Live Stream, 5/28/2026): Join Callstack engineers Szymon Chmal and Kewin Wereszczyński on May 21 at 5 PM to explore Redraw, a new 2D graphics library for WebGPU. - [Testing AI Agent Skills Reliably With Skill Gym](https://www.callstack.com/events/how-can-i-test-my-ai-agent-skills-reliably) (Live Stream, 5/14/2026): Learn how Skill Gym helps test, validate, and improve AI agent skills with repeatable workflows, assertions, and model-aware feedback. - [Shipping iOS Live Activities with React: The Voltra Story](https://www.callstack.com/events/shipping-ios-live-activities-with-react-the-voltra-story) (Talk, 4/23/2026): How Voltra enables Live Activities and Dynamic Island views using React without writing Swift. A deep dive into iOS constraints and architecture. - [How Skillgym Helps You Verify Agent Skills Still Work After Every Change](https://www.callstack.com/blog/how-skillgym-helps-you-verify-agent-skills-still-work) (Article, 4/17/2026): See how skillgym tests agent skills across runners, validates behavior, and catches regressions before your users do. - [Callstack x Vercel AI SDK Meetup](https://www.callstack.com/events/callstack-x-vercel-ai-sdk-meetup) (Meetup, 3/4/2026): Join the Callstack x Vercel AI SDK Meetup in Wrocław on March 4, 2026. Practical talks on building secure, production-ready AI apps. - [The Safe Detonation Chamber: Building AI You Can Actually Ship](https://www.callstack.com/events/the-safe-detonation-chamber-building-ai-you-can-actually-ship) (Talk, 3/4/2026): How to design production AI systems using Vercel AI SDK, Workflows, and Sandbox , covering vendor lock‑in, long‑running workflows, and secure code execution. - [JSX to Live Activity: The Story of Voltra](https://www.callstack.com/events/jsx-to-live-activity-the-story-of-voltra) (Talk, 2/5/2026): Learn how Voltra brings React to iOS Live Activities and Dynamic Island by translating JSX into SwiftUI through a custom React renderer. - [Live Activities and Widgets with React: Say Hello to Voltra](https://www.callstack.com/blog/live-activities-and-widgets-with-react-say-hello-to-voltra) (Article, 1/13/2026): Voltra lets you build iOS Live Activities and widgets for React Native using JSX instead of Swift. - [Building iOS Live Activities With React: Inside Voltra](https://www.callstack.com/events/building-ios-live-activities-with-react) (Live Stream, 12/18/2025): Learn how to build iOS Live Activities and Dynamic Island experiences using pure JSX, no Swift or native code required. - [Write Once, Test Everywhere: Cross-Platform Testing for React Native](https://www.callstack.com/events/write-once-test-everywhere-cross-platform-testing-for-react-native-2) (Talk, 12/9/2025): Join Szymon Chmal at WarsawJS #133 to explore cross-platform testing in React Native with a new approach powered by React Native Harness. - [How I Hacked React Native DevTools (And Built a Plugin Framework)](https://www.callstack.com/events/how-i-hacked-react-native-devtools-and-built-a-plugin-framework) (Talk, 11/28/2025): Learn how React Native DevTools work under the hood, and how to inject custom plugins with clean hooks and no forks. - [Introducing Solito 5 and the Web-Native Mindset](https://www.callstack.com/events/exploring-solito-5-building-cross-platform-apps-with-react-and-react-native) (Live Stream, 11/20/2025): Join us on November 20 for a deep dive into Solito 5 with its creator, Fernando Rojo, and the Callstack team. - [Hermes V1: What It Is, What It Isn’t, and What’s Next](https://www.callstack.com/events/hermes-v1-what-it-is-what-it-isnt-and-whats-next) (Live Stream, 11/6/2025): Łukasz Chludziński, Szymon Chmal, and Matt Hargett unpack Hermes V1, covering what’s new, what’s changing, and what’s ahead for React Native performance. - [React Native Harness, Next.js 16 Beta & Remix v3](https://www.callstack.com/events/react-native-harness-deep-dive) (Live Stream, 10/16/2025): This week’s Live Dev Session dives into React Native Harness with Szymon Chmal, explores the Next.js 16 Beta and Remix v3 “pre-drop,” and breaks down the biggest React and React Native updates from the community and React Alicante 2025. - [Introducing React Native Harness: Fast, Real-Device Testing for Native Modules](https://www.callstack.com/blog/introducing-react-native-harness-fast-real-device-testing-for-native-modules) (Article, 10/15/2025): React Native Harness lets you run Jest-style tests directly on devices and emulators. Fast, reliable, and CI-ready. It’s the easiest way to validate native behavior in React Native. - [Building React Native App for Vega OS](https://www.callstack.com/events/deep-dive-building-react-native-app-for-vega-os) (Live Stream, 10/2/2025): React 19.2 brings and useEffectEvent, new ideas for React state management arrive, and Vega OS debuts as a React Native-powered Linux OS. - [How I Hacked React Native DevTools (And Built a Plugin Framework)](https://www.callstack.com/events/how-i-hacked-react-native-devtools-and-built-a-plugin-framework-prague) (Talk, 9/16/2025): Learn how React Native DevTools work under the hood, and how to inject custom plugins with clean hooks and no forks. - [Live Dev Session: React Universe Conf, RN 1.0, Expo Updates & More](https://www.callstack.com/events/live-dev-session-week-37) (Live Stream, 9/11/2025): In Week 37 of our Live Dev Session we talked about React Universe Conf with guest Szymon, ranted about AI, explored what React Native 1.0 really means, reviewed Expo updates, and covered the latest moves in the React Native ecosystem. - [Rozenite: The Missing Part of React Native DevTools](https://www.callstack.com/events/rozenite-the-missing-part-of-react-native-devtools) (Talk, 9/4/2025): Learn how Rozenite hooks into DevTools to enable clean, custom plugin development, restoring the extensibility devs loved in Flipper. - [Live Dev Session: Rozenite DevTools Plugins Framework, Precompiled React Native for iOS, TanStack DB 0.1 ](https://www.callstack.com/events/live-dev-session-week-31) (Live Stream, 7/31/2025): Discover Rozenite: DevTools framework for React Native, faster iOS builds, on-device AI, and key updates from this week’s livestream. - [Introducing Rozenite: A Plugin Framework for React Native DevTools](https://www.callstack.com/blog/introducing-rozenite-a-plugin-framework-for-react-native-devtools) (Article, 7/28/2025): Build custom debugging panels inside React Native DevTools with Rozenite: a modular, TypeScript-ready plugin framework with full device-scoped support. - [Live Dev Session: Breaking Down Vercel Ship 2025](https://www.callstack.com/events/react-next-js-updates-from-vercel-ship-2025) (Live Stream, 6/27/2025): Tune in to developer reactions to Vercel Ship 2025, from AI sandboxes and bot detection to smarter compute pricing and microfrontends. - [Master JavaScript Performance in React Native (Part 2)](https://www.callstack.com/events/master-javascript-performance-in-react-native-part-2) (Webinar, 4/28/2025): Learn to fix JS performance issues in React Native-from debounce bugs to Redux selectors, in this hands-on webinar with real code examples. - [I Built a File-Based Router for React Native](https://www.callstack.com/events/i-built-a-file-based-router-for-react-native) (Talk, 4/16/2025): A deep dive into building a file-based router for React Native using Metro’s hidden APIs, dynamic routing, loading states, and smart hacks included. - [Master JavaScript Performance in React Native (Part 1)](https://www.callstack.com/events/master-javascript-performance-in-react-native-part-1) (Webinar, 4/15/2025): Watch Callstack's webinar on React Native JS performance. Learn to fix bottlenecks, leaks & FPS issues from the 2025 Ultimate Guide authors. - [Why Knowing Your App’s Bundle Contents Matters for React Native Performance](https://www.callstack.com/blog/knowing-your-apps-bundle-contents-native-performance) (Article, 3/20/2025): Learn why your React Native app’s bundle size matters & how tools like Expo Atlas help you optimize performance, reduce app startup time & improve dependency management. - [LynxJS: First Impressions, Live Coding & What’s Under the Hood](https://www.callstack.com/events/lynxjs-first-impressions-live-coding-whats-under-the-hood) (Live Stream, 3/10/2025): We’re checking out LynxJS for the first time! Join us as we test it out, see how it works, and share their thoughts. - [Create React App is Out: Exploring Alternatives & Community Proposals](https://www.callstack.com/events/create-react-app-is-out-exploring-alternatives-community-proposals) (Live Stream, 2/20/2025): CRA is now deprecated, so we explore other options for starting web React projects, going through Vite, TanStack Router, Parcel, and Rsbuild to check the developer experience. - [State of React 2024 Breakdown](https://www.callstack.com/events/state-of-react-2024-breakdown) (Live Stream, 2/13/2025): Let's take a deep dive into the long-awaited State of React survey from 2024; brace yourselves for a two-hour ride. - [What's New in Next.js 15](https://www.callstack.com/podcasts/whats-new-in-next-js-15) (Podcast, 11/6/2024): Tune in to our breakdown of everything new in Next.js 15, from React 19 and React Compiler support to Turbopack and secure Server Actions. - [Astro – Island Technology in the Name of Optimization](https://www.callstack.com/events/astro-island-technology-in-the-name-of-optimization) (Talk, 10/25/2024): Next.js is the default choice, but Astro offers strong competition in some areas. Let's compare their features and differences. JOIN US ## Build the AI-native React Native future Work with engineers who contribute to the ecosystem and turn new technology into real products. At Callstack, AI is part of how we build, learn, and ship software. [Join Us](https://www.callstack.com/careers) [About us](https://www.callstack.com/about-us)