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
Voltra lets you build iOS Live Activities with React.
Under the hood, it’s SwiftUI. ✨
The catch: SwiftUI “styles” are ordered transforms.
Voltra makes them deterministic, so you don’t have to care. 😎
Check it out: use-voltra.dev
Under the hood, it’s SwiftUI. ✨
The catch: SwiftUI “styles” are ordered transforms.
Voltra makes them deterministic, so you don’t have to care. 😎
Check it out: use-voltra.dev
January 27, 2026 at 1:04 PM
Voltra lets you build iOS Live Activities with React.
Under the hood, it’s SwiftUI. ✨
The catch: SwiftUI “styles” are ordered transforms.
Voltra makes them deterministic, so you don’t have to care. 😎
Check it out: use-voltra.dev
Under the hood, it’s SwiftUI. ✨
The catch: SwiftUI “styles” are ordered transforms.
Voltra makes them deterministic, so you don’t have to care. 😎
Check it out: use-voltra.dev
This Thursday in Berlin, we are holding the React Universe Meetup x @zalando.com.
Join us for talks by Eugene Verichev, @artus9033.bsky.social, @tej.as, and Mohit Karekar on React Native, on-device LLMs, health, and brownfield performance. There are only a few spots left. Sign up: clstk.com/4qBg77c
Join us for talks by Eugene Verichev, @artus9033.bsky.social, @tej.as, and Mohit Karekar on React Native, on-device LLMs, health, and brownfield performance. There are only a few spots left. Sign up: clstk.com/4qBg77c
January 27, 2026 at 11:18 AM
This Thursday in Berlin, we are holding the React Universe Meetup x @zalando.com.
Join us for talks by Eugene Verichev, @artus9033.bsky.social, @tej.as, and Mohit Karekar on React Native, on-device LLMs, health, and brownfield performance. There are only a few spots left. Sign up: clstk.com/4qBg77c
Join us for talks by Eugene Verichev, @artus9033.bsky.social, @tej.as, and Mohit Karekar on React Native, on-device LLMs, health, and brownfield performance. There are only a few spots left. Sign up: clstk.com/4qBg77c
TV apps run on tight hardware budgets.
The infographic breaks down why efficient list virtualization, smarter image handling, and lean startup paths matter on real TV devices.
Treat performance as part of the UX ⬇️
The infographic breaks down why efficient list virtualization, smarter image handling, and lean startup paths matter on real TV devices.
Treat performance as part of the UX ⬇️
January 23, 2026 at 2:22 PM
TV apps run on tight hardware budgets.
The infographic breaks down why efficient list virtualization, smarter image handling, and lean startup paths matter on real TV devices.
Treat performance as part of the UX ⬇️
The infographic breaks down why efficient list virtualization, smarter image handling, and lean startup paths matter on real TV devices.
Treat performance as part of the UX ⬇️
Building v0 iOS meant running into small things in React Native that just felt… off. Instead of working around them, the team patched React Native, reported issues, and upstreamed fixes so they could work beyond just one app.
Tune in to learn how working on v0 ended up making React Native better ⬇️
Tune in to learn how working on v0 ended up making React Native better ⬇️
January 23, 2026 at 11:35 AM
Building v0 iOS meant running into small things in React Native that just felt… off. Instead of working around them, the team patched React Native, reported issues, and upstreamed fixes so they could work beyond just one app.
Tune in to learn how working on v0 ended up making React Native better ⬇️
Tune in to learn how working on v0 ended up making React Native better ⬇️
Your React Native app… but on your face 🕶️ On Meta Quest, React Native apps run as 2D windows inside VR. Same JS, same Expo, same Metro.
Grab the full *React Native Developer’s Guide to Horizon OS* to see how to get started and what really changes in VR ⬇️
Grab the full *React Native Developer’s Guide to Horizon OS* to see how to get started and what really changes in VR ⬇️
January 22, 2026 at 2:22 PM
Your React Native app… but on your face 🕶️ On Meta Quest, React Native apps run as 2D windows inside VR. Same JS, same Expo, same Metro.
Grab the full *React Native Developer’s Guide to Horizon OS* to see how to get started and what really changes in VR ⬇️
Grab the full *React Native Developer’s Guide to Horizon OS* to see how to get started and what really changes in VR ⬇️
Many teams still ship WebViews in their mobile apps, often overlooking where React Native could help.
In his React Conf talk, @grabbou.com walks through adding React Native to an existing app and gradually replacing native code or WebViews.
Watch the talk here: clstk.com/45JxVVl
In his React Conf talk, @grabbou.com walks through adding React Native to an existing app and gradually replacing native code or WebViews.
Watch the talk here: clstk.com/45JxVVl
React Everywhere: Bringing React Into Native Apps | Callstack
Most teams use React on the web but still rely on native code or WebViews in their mobile apps. This talk explores how React Native can replace WebViews with minimal effort, allowing React to power bo...
clstk.com
January 21, 2026 at 2:49 PM
Many teams still ship WebViews in their mobile apps, often overlooking where React Native could help.
In his React Conf talk, @grabbou.com walks through adding React Native to an existing app and gradually replacing native code or WebViews.
Watch the talk here: clstk.com/45JxVVl
In his React Conf talk, @grabbou.com walks through adding React Native to an existing app and gradually replacing native code or WebViews.
Watch the talk here: clstk.com/45JxVVl
We’re releasing an alpha of Brownie.
Shared state for React Native brownfield apps, without custom Turbo Modules. Type-safe, native-first, and designed for real app lifecycles.
Read the article for a deeper look at how Brownie works 👉
clstk.com/3LHn9Iv
Shared state for React Native brownfield apps, without custom Turbo Modules. Type-safe, native-first, and designed for real app lifecycles.
Read the article for a deeper look at how Brownie works 👉
clstk.com/3LHn9Iv
January 20, 2026 at 3:17 PM
We’re releasing an alpha of Brownie.
Shared state for React Native brownfield apps, without custom Turbo Modules. Type-safe, native-first, and designed for real app lifecycles.
Read the article for a deeper look at how Brownie works 👉
clstk.com/3LHn9Iv
Shared state for React Native brownfield apps, without custom Turbo Modules. Type-safe, native-first, and designed for real app lifecycles.
Read the article for a deeper look at how Brownie works 👉
clstk.com/3LHn9Iv
Next week in Berlin: React Universe Meetup x @zalando.com.
The agenda is focused on real React Native work: shipping video at scale, running LLMs on-device, using RN with health data & performance comparisons in Brownfield.
Sign up now for practical lessons & real tradeoffs: clstk.com/4b8MVzM
The agenda is focused on real React Native work: shipping video at scale, running LLMs on-device, using RN with health data & performance comparisons in Brownfield.
Sign up now for practical lessons & real tradeoffs: clstk.com/4b8MVzM
January 20, 2026 at 1:42 PM
Next week in Berlin: React Universe Meetup x @zalando.com.
The agenda is focused on real React Native work: shipping video at scale, running LLMs on-device, using RN with health data & performance comparisons in Brownfield.
Sign up now for practical lessons & real tradeoffs: clstk.com/4b8MVzM
The agenda is focused on real React Native work: shipping video at scale, running LLMs on-device, using RN with health data & performance comparisons in Brownfield.
Sign up now for practical lessons & real tradeoffs: clstk.com/4b8MVzM
🚀 New from Callstack: the Ultimate Guide to React Native Optimization now has an agent-ready version.
It turns 9+ years of React Native and Expo production experience into skills AI agents can use inside modern AI-driven workflows.
Try it out today: [https://clstk.com/49tQYFB](clstk.com/49tQYFB)
It turns 9+ years of React Native and Expo production experience into skills AI agents can use inside modern AI-driven workflows.
Try it out today: [https://clstk.com/49tQYFB](clstk.com/49tQYFB)
January 19, 2026 at 11:21 AM
🚀 New from Callstack: the Ultimate Guide to React Native Optimization now has an agent-ready version.
It turns 9+ years of React Native and Expo production experience into skills AI agents can use inside modern AI-driven workflows.
Try it out today: [https://clstk.com/49tQYFB](clstk.com/49tQYFB)
It turns 9+ years of React Native and Expo production experience into skills AI agents can use inside modern AI-driven workflows.
Try it out today: [https://clstk.com/49tQYFB](clstk.com/49tQYFB)
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 ⬇️