Callstack
@callstack.com
We enable engineering teams to scale apps across mobile, web, and TV with React Native and our OSS. Hosts of @reactuniverseconf.com
Get to know us at www.callstack.com
Get to know us at www.callstack.com
At React Universe Meetup x @zalando.com in Berlin, Eugene Verichev will talk about building a production video experience with React Native, including lessons from early adoption of the new architecture and the tradeoffs behind it.
Join for practical takeaways and experience-driven talks ⬇️
Join for practical takeaways and experience-driven talks ⬇️
January 16, 2026 at 2:27 PM
At React Universe Meetup x @zalando.com in Berlin, Eugene Verichev will talk about building a production video experience with React Native, including lessons from early adoption of the new architecture and the tradeoffs behind it.
Join for practical takeaways and experience-driven talks ⬇️
Join for practical takeaways and experience-driven talks ⬇️
New guide alert 📖 We’ve just released React Native Developer’s Guide to Meta Horizon OS, a hands-on path to running RN apps on Meta Quest via Expo, plus notes on library compatibility, debugging/profiling, and publishing. Download it here: clstk.com/4qnefid
January 16, 2026 at 10:36 AM
New guide alert 📖 We’ve just released React Native Developer’s Guide to Meta Horizon OS, a hands-on path to running RN apps on Meta Quest via Expo, plus notes on library compatibility, debugging/profiling, and publishing. Download it here: clstk.com/4qnefid
Testing native modules is like verifying coffee pods.
☕ The slow way: Brewing whole pot (building a full UI)
🤷 The risky way: Just reading label (mocking the bridge)
🔎 The Harness way: Checking grounds directly (running JS tests in a real native environment)
Verify the actual flavor with Harness.
☕ The slow way: Brewing whole pot (building a full UI)
🤷 The risky way: Just reading label (mocking the bridge)
🔎 The Harness way: Checking grounds directly (running JS tests in a real native environment)
Verify the actual flavor with Harness.
January 15, 2026 at 1:31 PM
Testing native modules is like verifying coffee pods.
☕ The slow way: Brewing whole pot (building a full UI)
🤷 The risky way: Just reading label (mocking the bridge)
🔎 The Harness way: Checking grounds directly (running JS tests in a real native environment)
Verify the actual flavor with Harness.
☕ The slow way: Brewing whole pot (building a full UI)
🤷 The risky way: Just reading label (mocking the bridge)
🔎 The Harness way: Checking grounds directly (running JS tests in a real native environment)
Verify the actual flavor with Harness.
v0 iOS is a React Native app that forced the team to go all the way down the stack. This episode breaks down:
🟣 iOS-first constraints and benefits
🟣 Expo beyond the happy path
🟣 Yoga, gesture handling, and WebView internals
🟣 How production work shaped open source
Watch it at clstk.com/49RCTSm
🟣 iOS-first constraints and benefits
🟣 Expo beyond the happy path
🟣 Yoga, gesture handling, and WebView internals
🟣 How production work shaped open source
Watch it at clstk.com/49RCTSm
Shipping v0 iOS: React Native Without Compromises
A technical look at building v0 mobile with React Native and Expo, covering iOS-first decisions, native modules, and fixes pushed to React Native core. Featuring Fernando Rojo, Szymon Rybczak, and Osk...
clstk.com
January 14, 2026 at 12:10 PM
v0 iOS is a React Native app that forced the team to go all the way down the stack. This episode breaks down:
🟣 iOS-first constraints and benefits
🟣 Expo beyond the happy path
🟣 Yoga, gesture handling, and WebView internals
🟣 How production work shaped open source
Watch it at clstk.com/49RCTSm
🟣 iOS-first constraints and benefits
🟣 Expo beyond the happy path
🟣 Yoga, gesture handling, and WebView internals
🟣 How production work shaped open source
Watch it at clstk.com/49RCTSm
Reposted by Callstack
Close the laptop. Open the conversation.
We’re teaming up with @callstack.com for an in-person React Universe Meetup on 29 January 2026. It’s happening at our place – Zalando BHW.
Grab your spot here: lnkd.in/ermje4az
We’re teaming up with @callstack.com for an in-person React Universe Meetup on 29 January 2026. It’s happening at our place – Zalando BHW.
Grab your spot here: lnkd.in/ermje4az
![Purple digital banner with Zalando and Callstack logos. Headline: React Universe Meetup x Zalando, Berlin. Event details: Thursday, 29/01/2026 from 6 PM – 9 PM [CET]. Location: Zalando SE - BHW, Berlin.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:rgzrc6qo52g6u4gvhyi57uvt/bafkreiatubqp6wp24mxsoyc22mg2jpxcedvqmlky3mrgtkwkyflyb2ewtu@jpeg)
January 14, 2026 at 9:26 AM
Close the laptop. Open the conversation.
We’re teaming up with @callstack.com for an in-person React Universe Meetup on 29 January 2026. It’s happening at our place – Zalando BHW.
Grab your spot here: lnkd.in/ermje4az
We’re teaming up with @callstack.com for an in-person React Universe Meetup on 29 January 2026. It’s happening at our place – Zalando BHW.
Grab your spot here: lnkd.in/ermje4az
Native module testing does not have to mean heavy tooling.
This talk by @thymikee.bsky.social from @reactnativelondon.co.uk shows how React Native Harness enables testing real native behavior on devices while keeping a JavaScript and Jest-style workflow.
Watch it here: clstk.com/3Lo6U2V
This talk by @thymikee.bsky.social from @reactnativelondon.co.uk shows how React Native Harness enables testing real native behavior on devices while keeping a JavaScript and Jest-style workflow.
Watch it here: clstk.com/3Lo6U2V
Testing Native Modules Reliably With JavaScript | Callstack
Learn how React Native Harness bridges the gap between mocking and E2E testing: real device tests, full native access, Jest-style simplicity.
clstk.com
January 13, 2026 at 3:14 PM
Native module testing does not have to mean heavy tooling.
This talk by @thymikee.bsky.social from @reactnativelondon.co.uk shows how React Native Harness enables testing real native behavior on devices while keeping a JavaScript and Jest-style workflow.
Watch it here: clstk.com/3Lo6U2V
This talk by @thymikee.bsky.social from @reactnativelondon.co.uk shows how React Native Harness enables testing real native behavior on devices while keeping a JavaScript and Jest-style workflow.
Watch it here: clstk.com/3Lo6U2V
Voltra takes a different approach to Live Activities.
You describe the UI in JSX, ship it as data, and let SwiftUI render it natively. No fixed templates and no need to reach for Swift.
That flexibility lets you update Live Activity UI without shipping a new app version. Full story in the article.
You describe the UI in JSX, ship it as data, and let SwiftUI render it natively. No fixed templates and no need to reach for Swift.
That flexibility lets you update Live Activity UI without shipping a new app version. Full story in the article.
January 13, 2026 at 12:07 PM
Voltra takes a different approach to Live Activities.
You describe the UI in JSX, ship it as data, and let SwiftUI render it natively. No fixed templates and no need to reach for Swift.
That flexibility lets you update Live Activity UI without shipping a new app version. Full story in the article.
You describe the UI in JSX, ship it as data, and let SwiftUI render it natively. No fixed templates and no need to reach for Swift.
That flexibility lets you update Live Activity UI without shipping a new app version. Full story in the article.
At React Universe Meetup x @zalando.com in Berlin, @tej.as will connect health science and React Native, showing how engineers can use apps and fitness data to improve recovery, stress, and and unlock new levels of productivity.
Save your spot: link in the comments ⬇️
Save your spot: link in the comments ⬇️
January 12, 2026 at 4:04 PM
At React Universe Meetup x @zalando.com in Berlin, @tej.as will connect health science and React Native, showing how engineers can use apps and fitness data to improve recovery, stress, and and unlock new levels of productivity.
Save your spot: link in the comments ⬇️
Save your spot: link in the comments ⬇️
“Bias towards merging and releasing.” That mindset shaped the v0 iOS app: native feel, React Native under the hood, zero shortcuts.
New podcast episode with @psyche.social, @rojo.bsky.social, @kwasniew.ski, and @szymonrybczak.bsky.social is coming out soon, sign up for the YouTube premiere 👇
New podcast episode with @psyche.social, @rojo.bsky.social, @kwasniew.ski, and @szymonrybczak.bsky.social is coming out soon, sign up for the YouTube premiere 👇
January 12, 2026 at 1:39 PM
“Bias towards merging and releasing.” That mindset shaped the v0 iOS app: native feel, React Native under the hood, zero shortcuts.
New podcast episode with @psyche.social, @rojo.bsky.social, @kwasniew.ski, and @szymonrybczak.bsky.social is coming out soon, sign up for the YouTube premiere 👇
New podcast episode with @psyche.social, @rojo.bsky.social, @kwasniew.ski, and @szymonrybczak.bsky.social is coming out soon, sign up for the YouTube premiere 👇
Reposted by Callstack
React Universe Meetup is coming to Berlin, and I’ll be there speaking about on-device LLM inference in React Native.
There’s a short video attached with more context.
If you’re attending, would be great to meet in person! You can sign up here 👉 clstk.com/3LwiyZz
There’s a short video attached with more context.
If you’re attending, would be great to meet in person! You can sign up here 👉 clstk.com/3LwiyZz
January 9, 2026 at 11:43 AM
React Universe Meetup is coming to Berlin, and I’ll be there speaking about on-device LLM inference in React Native.
There’s a short video attached with more context.
If you’re attending, would be great to meet in person! You can sign up here 👉 clstk.com/3LwiyZz
There’s a short video attached with more context.
If you’re attending, would be great to meet in person! You can sign up here 👉 clstk.com/3LwiyZz
Meet one of our speakers!
@artus9033.bsky.social invites you to the React Universe Meetup we’re hosting in Berlin with Zalando on January 29. Expect real production lessons, architectural tradeoffs and honest discussions!
clstk.com/49sHadt
@artus9033.bsky.social invites you to the React Universe Meetup we’re hosting in Berlin with Zalando on January 29. Expect real production lessons, architectural tradeoffs and honest discussions!
clstk.com/49sHadt
Join Artur Morys-Magiera at React Universe Meetup with Zalando in Berlin
YouTube video by Callstack
www.youtube.com
January 9, 2026 at 12:09 PM
Meet one of our speakers!
@artus9033.bsky.social invites you to the React Universe Meetup we’re hosting in Berlin with Zalando on January 29. Expect real production lessons, architectural tradeoffs and honest discussions!
clstk.com/49sHadt
@artus9033.bsky.social invites you to the React Universe Meetup we’re hosting in Berlin with Zalando on January 29. Expect real production lessons, architectural tradeoffs and honest discussions!
clstk.com/49sHadt
A quick reminder: we’re still accepting talk proposals for the React Universe Meetup with @zalando.com in Berlin on January 29.
Practical React Native, mobile, or cross-platform lessons welcome. Submit your proposal by January 15 to become one of our speakers. Link below ⬇️
Practical React Native, mobile, or cross-platform lessons welcome. Submit your proposal by January 15 to become one of our speakers. Link below ⬇️
January 2, 2026 at 1:04 PM
A quick reminder: we’re still accepting talk proposals for the React Universe Meetup with @zalando.com in Berlin on January 29.
Practical React Native, mobile, or cross-platform lessons welcome. Submit your proposal by January 15 to become one of our speakers. Link below ⬇️
Practical React Native, mobile, or cross-platform lessons welcome. Submit your proposal by January 15 to become one of our speakers. Link below ⬇️
It was nearly Christmas. The offices had grown quiet. Most machines had been shut down and left to rest. And yet, somewhere, a terminal still glowed, keeping watch over one last evening of unfinished business…
Give A (Secure) Christmas Carol a listen before you close the laptop for the holidays ⬇️
Give A (Secure) Christmas Carol a listen before you close the laptop for the holidays ⬇️
December 23, 2025 at 11:06 AM
It was nearly Christmas. The offices had grown quiet. Most machines had been shut down and left to rest. And yet, somewhere, a terminal still glowed, keeping watch over one last evening of unfinished business…
Give A (Secure) Christmas Carol a listen before you close the laptop for the holidays ⬇️
Give A (Secure) Christmas Carol a listen before you close the laptop for the holidays ⬇️
React Native growth in 2025 tells a clear story. 📖
More apps, more platforms, more companies, and a strong community pushing things forward.
We wrapped the numbers and the people behind them in React Native Wrapped 2025.
The full 2025 recap is below ⬇️
More apps, more platforms, more companies, and a strong community pushing things forward.
We wrapped the numbers and the people behind them in React Native Wrapped 2025.
The full 2025 recap is below ⬇️
December 22, 2025 at 2:50 PM
React Native growth in 2025 tells a clear story. 📖
More apps, more platforms, more companies, and a strong community pushing things forward.
We wrapped the numbers and the people behind them in React Native Wrapped 2025.
The full 2025 recap is below ⬇️
More apps, more platforms, more companies, and a strong community pushing things forward.
We wrapped the numbers and the people behind them in React Native Wrapped 2025.
The full 2025 recap is below ⬇️
TV interfaces follow their own rules. Bigger typography, strong contrast, predictable focus, and simple layouts form the core of the 10‑foot experience. The Ultimate Guide walks through these fundamentals ➡️
December 22, 2025 at 12:05 PM
TV interfaces follow their own rules. Bigger typography, strong contrast, predictable focus, and simple layouts form the core of the 10‑foot experience. The Ultimate Guide walks through these fundamentals ➡️
React Universe Meetup with @zalando.com is coming to Berlin. We’re focusing on React Native in production: video at scale, new architecture, and on-device LLMs.
Sign up to attend and join the discussion, CFP is also open for talk submissions ⬇️
Sign up to attend and join the discussion, CFP is also open for talk submissions ⬇️
December 22, 2025 at 9:40 AM
React Universe Meetup with @zalando.com is coming to Berlin. We’re focusing on React Native in production: video at scale, new architecture, and on-device LLMs.
Sign up to attend and join the discussion, CFP is also open for talk submissions ⬇️
Sign up to attend and join the discussion, CFP is also open for talk submissions ⬇️
Why JS minification is redundant in React Native? If you come from the web, minifying JS for production feels automatic. In React Native, it’s different. Hermes compiles JS to bytecode and handles dead code elimination, so minification is off by default.
Learn more: link below 👇
Learn more: link below 👇
December 18, 2025 at 2:39 PM
Why JS minification is redundant in React Native? If you come from the web, minifying JS for production feels automatic. In React Native, it’s different. Hermes compiles JS to bytecode and handles dead code elimination, so minification is off by default.
Learn more: link below 👇
Learn more: link below 👇
Next.js is ditching the static vs. dynamic split. Aurora Scharff explains the new unified model built on Server Components. Now, you suspend your dynamic content, and the rest will be statically rendered. She also covers how it helps you find the right Suspense boundaries ⬇️ clstk.com/4pL4ydt
Beyond Static vs. Dynamic: Next.js's New Unified Model
Aurora Scharff (Crayon Consulting) explains how Next.js is moving to a unified model that ends the static/dynamic split and helps developers manage Suspense boundaries.
clstk.com
December 18, 2025 at 8:50 AM
Next.js is ditching the static vs. dynamic split. Aurora Scharff explains the new unified model built on Server Components. Now, you suspend your dynamic content, and the rest will be statically rendered. She also covers how it helps you find the right Suspense boundaries ⬇️ clstk.com/4pL4ydt
The breakthrough came from instrumenting TVM’s OpenCL backend. 👀
Artur Morys-Magiera & Ruihang Lai enabled command queue profiling with clGetEventProfilingInfo. It turned a UI freeze into a short list of kernels.
Discover the whole story in our latest article. Link below 👇
Artur Morys-Magiera & Ruihang Lai enabled command queue profiling with clGetEventProfilingInfo. It turned a UI freeze into a short list of kernels.
Discover the whole story in our latest article. Link below 👇
December 17, 2025 at 2:27 PM
The breakthrough came from instrumenting TVM’s OpenCL backend. 👀
Artur Morys-Magiera & Ruihang Lai enabled command queue profiling with clGetEventProfilingInfo. It turned a UI freeze into a short list of kernels.
Discover the whole story in our latest article. Link below 👇
Artur Morys-Magiera & Ruihang Lai enabled command queue profiling with clGetEventProfilingInfo. It turned a UI freeze into a short list of kernels.
Discover the whole story in our latest article. Link below 👇
This year, we're doing something different for Christmas 🎄A senior engineer, a quiet Christmas Eve, and warnings that were easier to ignore than fix. A (Secure) Christmas Carol, written and narrated by @psyche.social, is now live. Best listened to in one sitting ❄️ clstk.com/44QNgDl
December 16, 2025 at 1:58 PM
This year, we're doing something different for Christmas 🎄A senior engineer, a quiet Christmas Eve, and warnings that were easier to ignore than fix. A (Secure) Christmas Carol, written and narrated by @psyche.social, is now live. Best listened to in one sitting ❄️ clstk.com/44QNgDl
React Native tests don’t have to choose between speed and realism. At React Alicante 2025, @lukasz.app presents React Native Harness: Jest-style tests running on real devices, with native modules and no mocks by default. Watch the full recording ⬇️ clstk.com/4aiVdEF
Write Once, Test Everywhere: Cross-Platform Testing for React Native | Callstack
Cross-platform testing in React Native made simple: a lightweight architecture to run and extend tests on any JavaScript-powered platform.
clstk.com
December 16, 2025 at 6:30 AM
React Native tests don’t have to choose between speed and realism. At React Alicante 2025, @lukasz.app presents React Native Harness: Jest-style tests running on real devices, with native modules and no mocks by default. Watch the full recording ⬇️ clstk.com/4aiVdEF
TV ecosystems are fragmented, but React Native brings them together. With shared JS code and platform support like react-native-tvos, you can target major TV platforms through a single, adaptable framework. Our guide shows how this approach eases development ➡️ clstk.com/3MKcYTw
Use React Native to Navigate the Fragmented TV Ecosystem | Callstack
Explore the living-room landscape with a comprehensive guide to React Native TV app development. Learn how platforms differ, how to design remote-friendly interfaces, how to manage focus and navigatio...
clstk.com
December 15, 2025 at 1:05 PM
TV ecosystems are fragmented, but React Native brings them together. With shared JS code and platform support like react-native-tvos, you can target major TV platforms through a single, adaptable framework. Our guide shows how this approach eases development ➡️ clstk.com/3MKcYTw
Switching between Storybook and your app is now easier than ever. With Metro updates, the new Storybook helper, and Expo env vars, the workflow is insanely smooth.
Read our new guide by @dannyhw.com: clstk.com/44mRAd6
It covers everything you need to know!
Read our new guide by @dannyhw.com: clstk.com/44mRAd6
It covers everything you need to know!
December 12, 2025 at 9:25 AM
Switching between Storybook and your app is now easier than ever. With Metro updates, the new Storybook helper, and Expo env vars, the workflow is insanely smooth.
Read our new guide by @dannyhw.com: clstk.com/44mRAd6
It covers everything you need to know!
Read our new guide by @dannyhw.com: clstk.com/44mRAd6
It covers everything you need to know!
What's changed since Expo became the default React Native framework? Jon Samp discusses the framework's evolution, why the hobby tool perception is outdated, and details the launch of the new Expo App Awards.
Full interview ▶️ clstk.com/3YneCgq
Full interview ▶️ clstk.com/3YneCgq
From Hobby Tool to Default: Expo's Journey and the New App Awards
Jon Samp (Expo) discusses the framework's evolution since becoming the React Native default, the death of the
clstk.com
December 11, 2025 at 11:03 AM
What's changed since Expo became the default React Native framework? Jon Samp discusses the framework's evolution, why the hobby tool perception is outdated, and details the launch of the new Expo App Awards.
Full interview ▶️ clstk.com/3YneCgq
Full interview ▶️ clstk.com/3YneCgq
In September, @thymikee.bsky.social and @kwasniew.ski took the stage at GOSIM Hangzhou in China. Their talk on Native Apps Without a Build Step is now available on the @gosimfoundation.bsky.social YouTube channel and on our page.
Check it out: clstk.com/4pysDUH
Check it out: clstk.com/4pysDUH
Native Apps Without a Build Step | Callstack
Discover Rock by Callstack: the open, modular, self-hosted framework for React Native. Built to help teams scale, migrate, and deliver faster in the evolving React Native ecosystem.
clstk.com
December 10, 2025 at 1:55 PM
In September, @thymikee.bsky.social and @kwasniew.ski took the stage at GOSIM Hangzhou in China. Their talk on Native Apps Without a Build Step is now available on the @gosimfoundation.bsky.social YouTube channel and on our page.
Check it out: clstk.com/4pysDUH
Check it out: clstk.com/4pysDUH