--- title: "React Native Harness, Next.js 16 Beta & Remix v3" description: "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." url: https://www.callstack.com/events/react-native-harness-deep-dive updated: 2026-10-24T08:39:21.785Z --- # React Native Harness, Next.js 16 Beta & Remix v3 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. _Livestream · 10/16/2025, 5PM [CEST] · Online · Recording: 02:57:15 · Category: Testing_ Organizer: Callstack Speakers: Łukasz Chludziński (Engineering Manager @ Callstack), Kewin Wereszczyński (Software Engineer @ Callstack), Szymon Chmal (Software Developer @ Callstack) [Watch the recording](https://www.youtube.com/watch?v=iMSHyiHbbFM) This week’s livestream brought a packed agenda of updates across the React and React Native ecosystem. As always, the discussion was based on insights from the [This Week in React](https://thisweekinreact.com/) newsletter. Here’s a summary of the key topics and announcements. ## React Native Harness: fast and real testing The highlight of the stream was a conversation with [Szymon Chmal](https://callstack.com/blog/introducing-react-native-harness-fast-real-device-testing-for-native-modules), author of React Native Harness a new testing solution that bridges the long-standing gap between fast unit tests and real-world end-to-end scenarios. Testing in React Native has traditionally meant choosing between speed and realism: - Fast: Jest-based unit and component tests. - Real: Full E2E tests covering complete user flows. Native modules and spec compliance often didn’t fit neatly into either category. React Native Harness introduces a middle ground that delivers both. ### Why it matters - Runs tests directly on device or emulator. - Uses familiar Jest syntax. - No mocks by default. Harness enables native testing that’s both _fast_ and _real_, making it practical again for complex native integrations. It’s already in action in [react-native-mmkv](https://github.com/mrousavy/react-native-mmkv/pull/918), where real-device tests validate native functionality. Read the full article [here](https://callstack.com/blog/introducing-react-native-harness-fast-real-device-testing-for-native-modules). ## Framework updates ### Next.js 16 Beta Released just before Next.js Conf, the Next.js 16 Beta marks a major step forward for the framework: - Turbopack is now stable - React Compiler support is stable (opt-in) - React 19.2 adds ``, View Transitions, and `useEffectEvent` - Persistent caching in dev mode for faster reloads Read more on the [Next.js blog](https://nextjs.org/blog/next-16-beta). ### Remix v3 “pre-drop” Another big announcement this week came from the Remix team: Remix v3 is no longer built on React. In a detailed three-hour presentation, Ryan Florence and Michael Jackson outlined a new architecture built on web platform primitives. Key highlights include: - JSX remains, but re-renders are manual. - A composable event system exists outside components. - The new `` component reintroduces a Suspense-like flow. - The framework is now focused fully on web-native primitives. Watch the full presentation [on YouTube](https://youtube.com/watch?v=xt_iEOn2a6Y&t=11764s). ## React Alicante 2025 recap React Alicante 2025 delivered a strong lineup of speakers, engaging talks, and a vibrant community atmosphere. For a comprehensive summary of the event, check out [Kate Marshalkina’s recap](https://kalabro.tech/react-alicante-2025/). ## Other highlights - Expo is introducing first-class CSS and Tailwind support, as [announced by Evan Bacon](https://x.com/Baconbrix/status/1976050536756691384). - This represents a major step toward consistent styling across React Native and web. - React Native Screens will soon include Native Split View support, enabling multi-pane layouts powered by native navigation primitives.[ See the announcement](https://x.com/swmansion/status/1978099822860058806). - React Conf 2025 brought several React Native updates, summarized in [our latest newsletter](https://www.callstack.com/newsletters/all-lights-on-react-conf-2025-big-moves-for-react-react-native-september-2025). - The latest episode of the React Universe on Air podcast features the NFL team, exploring how React Native powers large-scale applications.[ Watch on YouTube](https://youtube.com/watch?v=gJdydItq6tE). - Additional Callstack-related highlights from the newsletter include:[‍](https://github.com/react-native-community/discussions-and-proposals/pull/947) - [React Native discussions & proposals](https://github.com/react-native-community/discussions-and-proposals/pull/947)[‍](https://callstack.com/blog/from-files-to-buffers-building-real-time-audio-pipelines-in-react-native) - [Real-time audio pipelines in React Native](https://callstack.com/blog/from-files-to-buffers-building-real-time-audio-pipelines-in-react-native)[‍](https://github.com/callstackincubator/react-native-harness) - [React Native Harness repository](https://github.com/callstackincubator/react-native-harness) ## Final thoughts This week’s stream covered a broad spectrum, from framework breakthroughs to new tooling for more realistic testing in React Native. Special thanks to Szymon Chmal, Kewin Wereszczyński, and theThis Week in React team: [Sebastien Lorber](https://x.com/sebastienlorber), [Kacper Kapuściak](https://x.com/kacperkapusciak), and [Krzysztof Piaskowy](https://x.com/piaskowyk) for curating yet another rich edition of the newsletter.