--- title: "Kewin Wereszczyński" description: "Kewin Wereszczyński moved from testing into a frontend lead role. Away from code: 3D graphics, film and plenty of AI. Meet the Callstack engineering team." url: https://www.callstack.com/team/kewin-wereszczynski updated: 2026-10-22T14:18:27.999Z --- # Kewin Wereszczyński Kewin Wereszczyński moved from testing into a frontend lead role. Away from code: 3D graphics, film and plenty of AI. Meet the Callstack engineering team. _Software Engineer_ Started his career as a tester before transitioning into programming, working on numerous startup projects as a solo frontend developer or in small teams. His biggest achievement was becoming a frontend lead on one of the projects. Passionate about 3D graphics, games, special effects, photography, and cinematography, he has also explored being a rock band vocalist, English stand-up performer, improviser, and YouTuber. Recently, he has become a bit obsessed with AI. [LinkedIn](https://www.linkedin.com/in/kwereszczynski/) · [X](https://x.com/Q1w1N) · [GitHub](https://github.com/Q1w1N) ## What I’ve been shipping - [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. - [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. - [Graph Agentic Coding Extends AI Workflows](https://www.callstack.com/events/how-graph-agentic-coding-extends-ai-workflows) (Live Stream, 8/27/2026): How connected state, retrieval, memory, and verification carry coding agents across complex, multi-step workflows. Kewin Wereszczyński and Lech Kalinowski discuss the structures that let agents plan, retrieve context, use tools, and keep working across longer tasks. - [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. - [How We Built a React Native News Agent With Eve](https://www.callstack.com/events/build-a-react-native-news-agent-with-eve) (Live Stream, 7/30/2026): See how we built and deployed an Eve agent that tracks React and React Native repositories, filters commit noise, and publishes daily Slack updates. - [How to Teach Your Own AI Model, Part 2: What Should You Build First?](https://www.callstack.com/events/how-to-teach-your-own-ai-model-part-2-what-should-you-build-first) (Live Stream, 7/16/2026): Explore practical AI model training, from choosing a first project and preparing data to fine-tuning locally and evaluating synthetic data. - [Building AI Agents With Eve: Tools, Skills, and Evals](https://www.callstack.com/events/can-eve-make-ai-agents-easier-to-build-and-run) (Live Stream, 7/2/2026): Learn how Eve helps structure AI agents with tools, skills, sandboxes, local models, HTTP channels, and evals. - [Training AI Is More Than Feeding It the Internet](https://www.callstack.com/events/how-to-teach-your-own-ai-model) (Live Stream, 6/18/2026): A Live Stream with Kewin Wereszczyński and Piotr Miłkowski on AI training, datasets, tokenization, alignment, and why models infer patterns rather than understand meaning. - [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. - [Improve Your AI Coding Workflow With Cursor Tips and Tricks](https://www.callstack.com/events/improve-your-ai-coding-workflow-with-cursor-tips-and-tricks) (Live Stream, 5/7/2026): Explore practical tips for working with AI coding agents, managing context, using skills, reviewing code, and choosing the right models. - [Build a React Native App With the TanStack Stack](https://www.callstack.com/events/build-a-react-native-app-with-the-tanstack-stack) (Live Stream, 4/30/2026): Join Callstack’s live stream on building a React Native app from the ground up using the TanStack toolbelt. - [React Native 0.85: Animation Backend and Key Updates](https://www.callstack.com/events/react-native-updates-whats-new-and-what-matters) (Live Stream, 4/16/2026): A recap of React Native 0.85, covering the new animation backend, DevTools improvements, and ecosystem takeaways. - [Expo UI with SwiftUI and Jetpack Compose in practice](https://www.callstack.com/events/expo-ui-meets-native-jetpack-compose-and-swiftui-in-practice) (Live Stream, 3/26/2026): Exploring Expo UI with SwiftUI and Jetpack Compose, including setup challenges, architecture tradeoffs, and real-world developer insights. - [Agent Device, AI workflows, and mobile testing in practice](https://www.callstack.com/events/agent-device-ai-agents-meet-mobile-automation) (Live Stream, 3/19/2026): A discussion on Agent Device, AI-driven workflows, and testing mobile apps using simulators and accessibility data. - [React Native Evals: Measuring AI Code Quality in Practice](https://www.callstack.com/events/react-native-evals-making-ai-code-quality-measurable) (Live Stream, 3/12/2026): React Native Evals introduces a data-driven way to measure how AI coding models perform on real React Native development tasks. - [OpenClaw, Hermes Node and the State of AI Tooling](https://www.callstack.com/events/a-deep-dive-into-openclaw-and-react-native-news) (Live Stream, 2/26/2026): Kewin Wereszczyński and Daniel Williams discuss OpenClaw, Hermes Node, Markdown rendering, AI coding tools and the current AI landscape - [React Native 0.84: Hermes v1, WebAssembly, and Ecosystem Shifts](https://www.callstack.com/events/react-native-0-84-and-other-news) (Live Stream, 2/19/2026): React Native 0.84 introduces Hermes v1 by default, iOS prebuilt binaries, WebAssembly support, and improved tooling across the ecosystem. - [Sparkling: A New Framework for Lynx](https://www.callstack.com/events/sparkling-a-new-framework-for-lynx) (Live Stream, 2/12/2026): Join the Lynx team live as we explore Sparkling, its boundaries with Lynx, core features, and bootstrap a project from scratch. - [Storybook Explained: From Basics to Advanced Workflows](https://www.callstack.com/events/storybook-explained-from-101-to-advanced-workflows) (Live Stream, 2/5/2026): Core Storybook concepts, stories and args, interaction testing, and how Storybook works in React Native projects. - [Exploring Skills in Claude: A Live Walkthrough](https://www.callstack.com/events/exploring-dynamic-skills-in-claude) (Live Stream, 1/29/2026): Live experiments with Claude Skills in a React Native codebase, covering AI agents, Expo upgrades, and practical limits of automation - [React and React Native Weekly Breakdown](https://www.callstack.com/events/react-and-react-native-weekly-breakdown) (Live Stream, 1/22/2026): Join Callstack engineers for a live discussion on this week’s most important React and React Native updates, trends, and ecosystem shifts. - [React and React Native in 2026: Architecture, Nitro, and What’s Next](https://www.callstack.com/events/react-and-react-native-the-year-kick-off) (Live Stream, 1/15/2026): New architecture adoption, Nitro modules, React Strict DOM, Hermes v1, and ecosystem shifts shaping React and React Native in 2026. - [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. - [React Native 0.83: A Stability-Focused Release With Surprisingly Big Quality-of-Life Wins](https://www.callstack.com/events/react-native-0-83) (Live Stream, 12/11/2025): Join Łukasz Kewin for a walkthrough of React Native 0.83, recent ecosystem news, and hands-on demos. - [React Native on Meta Quest: What We Learned About Building for VR](https://www.callstack.com/events/react-native-on-meta-quest-a-developers-guide-to-building-for-vr) (Live Stream, 12/4/2025): See Meta Quest used as a practical dev setup and watch the team build and test React Native features directly inside a VR workspace. - [Two Threads of Lynx.js Part 2](https://www.callstack.com/events/two-threads-of-lynx-js-part-2) (Live Stream, 12/2/2025): Learn how Lynx.js uses a dual-threaded model, how its APIs work, and what it means for performance in this live session with Lukasz Chludzinski and Kewin Wereszczynski. - [Exploring Lynx.js and Its Two-Thread Runtime](https://www.callstack.com/events/two-threads-of-lynx-js) (Live Stream, 11/27/2025): A recap of our live session exploring how Lynx.js splits work across a main thread and a background thread. - [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. - [Inside Valdi: What We Learned Exploring Snapchat’s New UI Framework](https://www.callstack.com/events/valdi-snapchats-new-cross-platform-framework) (Live Stream, 11/13/2025): A hands-on look at Valdi, Snapchat’s new UI framework: setup, architecture, rendering model, and early developer impressions. - [Reanimated, TanStack, Cross-Pollinating Languages & TWIR #256 Anniversary](https://www.callstack.com/events/build-complex-animations-without-killing-performance-with-reanimated-4) (Live Stream, 10/30/2025): Catch up on everything from TanStack updates and Astro insights to Reanimated deep dive and even Swift for Android. Plus, we celebrate the 256th newsletter! - [Building Real-Time Live Activities in Expo](https://www.callstack.com/events/implementing-ios-live-activities-in-react-native) (Live Stream, 10/23/2025): Learn how to add real-time LiveActivity updates to your Expo app using Swift native modules. In this stream, we implemented Apple’s Live Activities with Evan Bacon’s library, explored ActivityKit, and discussed cross-platform development with Solito 5 and Expo UI. - [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. - [React Native Conf 2025: React Foundation, Compiler 1.0 & Future of React Native](https://www.callstack.com/events/live-dev-session-react-conf-2025-recap) (Live Stream, 10/9/2025): React Native Conf 2025 brought huge announcements: React Foundation under Linux Foundation, React Compiler 1.0 and Hermes v1. What’s next for React Native and newest React Features. - [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. - [Live Dev Session: , Expo SDK 54, Router v6, Lynx 3.4, TanStack Start](https://www.callstack.com/events/live-dev-session-week-39) (Live Stream, 9/25/2025): A packed week in the React ecosystem: React experiments with a new component, Expo SDK 54 speeds up builds, Expo Router v6 adds native-like navigation, Lynx 3.4 ships inputs & dev tools, TanStack Start hits RC, and React Router previews Framework Mode. - [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. - [Live Dev Session: Routers, React Native AI, and Expo Launch](https://www.callstack.com/events/live-dev-session-week-35) (Live Stream, 8/28/2025): Nuqs 2.5, Remix v3, Expo Launch, SPM support in React Native, the Jest RFC, and native Text-to-Speech with guest insights from Mike Grabowski. - [Live Dev Session: Expo SDK 54 Beta Is Here, Next.js 15.5, RNEF Renamed Rock](https://www.callstack.com/events/live-dev-session-week-34) (Live Stream, 8/21/2025): Explore what's new in Expo SDK 54 Beta: Liquid Glass, faster iOS builds, RN 0.81, and more dev upgrades from this week's livestream. - [Live Dev Session: FlashList v2, Vercel AI SDK, React Compiler](https://www.callstack.com/events/live-dev-session-week-32) (Live Stream, 8/7/2025): This week's livestream highlighted two major releases reshaping the React and React Native landscape: FlashList v2 and Vercel AI SDK 5. - [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. - [Live Dev Session: Reanimated 4, Worklets, React Native Screens](https://www.callstack.com/events/live-dev-session-week-30) (Live Stream, 7/24/2025): This week was packed with insights on highly anticipated Reanimated 4, the power of Worklets, Screens and more. - [Performant and Cross-Platform Shimmers in React Native Apps](https://www.callstack.com/blog/performant-and-cross-platform-shimmers-in-react-native-apps) (Article, 7/21/2025): A modern shimmer library for React Native with smooth UI skeletons, minimal dependencies, and optimized performance using Reanimated and SVG. Drop-in ready with full customization and shared animation state. - [Live Dev Session: Node-API, Wallets & Worklets in React Native](https://www.callstack.com/events/live-dev-session-week-29) (Live Stream, 7/16/2025): Node-API in RN, Apple’s LLM, react-native-wallet, ChromeOS rumors. The Week 29 React Native stream breaks it all down with some code and a lot of commentary. - [Live Dev Session: Unistyles 3.0, SSR With Hermes & Expo SDK 52](https://www.callstack.com/events/live-dev-session-week-28-react-react-native-rundown) (Live Stream, 7/10/2025): From inside shadows to decentralized music players, catch the latest React Native takes in Week 28 live dev session with Łukasz, Kewin, and Mike. - [Live Dev Session: Exploring Skia, Nitro Modules & UI Playgrounds](https://www.callstack.com/events/live-dev-session-react-react-native-week-27) (Live Stream, 7/3/2025): Live dev stream exploring Skia, Nitro Modules, AI app builders, and React Native tools; plus side quests into canvas UIs, Lottie, and pizza-coded joy. - [Live Dev Session: React Native Styling, OTA, and UI Tools](https://www.callstack.com/events/live-dev-session-react-universe-news-tools-code-2) (Live Stream, 6/17/2025): Tune in to a live session unpacking React Native 0.80, OTA alternatives, AI-generated UIs, styling wars, and some truly wild tech tangents. - [Live Dev Session: First Impressions of Apple’s On-Device AI](https://www.callstack.com/events/live-dev-session-react-universe-news-tools-code) (Live Stream, 6/10/2025): Tune in to dev chat on Apple’s AI SDK, iOS 26 naming chaos, Siri’s limits, Liquid Glass UI, and on-device LLMs. - [How I Used MCP to Control My Friend's Home](https://www.callstack.com/blog/model-context-protocol-in-action-with-real-use-and-real-code) (Article, 6/4/2025): Learn how MCP works with a hands-on project that connects Claude AI to smart home data using a Node.js server. - [Run LLMs Locally With React Native & MLC](https://www.callstack.com/events/run-llms-locally-with-react-native-mlc) (Live Stream, 6/3/2025): Watch how MLC brings on-device AI to React Native. See react-native-ai in action and discover what’s next for local model execution. - [Want to Run LLMs on Your Device? Meet MLC](https://www.callstack.com/blog/want-to-run-llms-on-your-device-meet-mlc) (Article, 5/28/2025): Find out how MLC compiles both model and runtime for efficient local LLM inference, and what that means for running AI on your Android or iOS app. - [Meet react-native-ai: LLMs Running on Mobile, for Real](https://www.callstack.com/blog/meet-react-native-ai-llms-running-on-mobile-for-real) (Article, 5/15/2025): Run AI models on-device in React Native apps using the new react-native-ai library, powered by MLC and Vercel AI SDK. Learn how it works and why it matters. - [Local LLMs on Mobile Are a Gimmick-For Now](https://www.callstack.com/blog/local-llms-on-mobile-are-a-gimmick) (Article, 3/11/2025): Can local LLMs replace cloud-based AI? We analyze performance, limitations, and the future of on-device AI models in 2025. - [Giving AI The Keys to Your App: Agents Controlling UI State](https://www.callstack.com/blog/giving-ai-the-keys-to-your-app-agents-controlling-ui-state) (Article, 2/4/2025): Learn how to let AI agents control UI state in React using Jotai and Flows-AI, automating logic and workflows for smarter, autonomous applications. - [Building AI Agent Workflows With Vercel’s AI SDK: A Practical Guide](https://www.callstack.com/blog/building-ai-agent-workflows-with-vercels-ai-sdk-a-practical-guide) (Article, 1/17/2025): Learn to build AI Agent workflows with Vercel's AI SDK. Explore chaining, routing, parallel & evaluator-optimizer patterns. - [Building a Custom AI Assistant for Your Business](https://www.callstack.com/podcasts/building-a-custom-ai-assistant-for-your-business) (Podcast, 11/25/2024): Learn what it takes to build a custom AI-powered chatbot for your company, including the challenges, solutions, performance, and security considerations. - [Creating a Video Transcription App: Lessons Learned](https://www.callstack.com/blog/creating-a-video-transcription-app-lessons-learned) (Article, 12/1/2023): Read about Callstack's R&D journey into AI for a transcription app, using OpenAI's Whisper for speech recognition. Discover the lessons learned. 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)