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Callstack Engineers
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Callstack Engineers
@callstackio
We ship cross-platform products at AI speed. Training LLMs (Apex). React Native Core Contributors & React Foundation Members. Bringing you @AgentConf.
Wroclaw, Poland
callstack.com
Joined August 2016
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  • Callstack Engineers reposted
    user avatar
    Piotr Miłkowski
    @xeonbloomfield
    13h
    Apex by @callstackio just got an update. The latest RN libraries? ✅ Runs on this week's Gemma update? ✅ Fixes for reported issues? ✅ Wide beta starts next week! Request access here: callstack.com/blog/introduci…
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  • Callstack Engineers reposted
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    ROFI
    @bidah
    Jul 16
    agent-device.dev is the most revolutionary technology that had happened to React Native since Expo. Is that good. It's for UI and Logic too. Any issue that arises through testing the app will show up in the server logs that the agent will fix too. Any UI issue can be
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    Callstack Engineers
    @callstackio
    Jul 16
    How to Teach Your Own AI Model, Part 2: What Should You Build First?
    4600460
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    Callstack Engineers
    @callstackio
    Jul 16
    Simple motion should not always require complex machinery. @lukasz_app talks with @janicduplessis from @appandflow about React Native Ease, the gap it fills, where Reanimated still wins, and why less work can matter for simple transitions ⬇️
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    00:00
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    Callstack Engineers
    @callstackio
    Jul 16
    Watch the episode ➡️
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    React Native Ease: Platform-Native Animations Without the Extra Work
    From callstack.com
    2150215
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    Callstack Engineers
    @callstackio
    Jul 16
    Who are we seeing next week?
    user avatar
    Michał Pierzchała
    @thymikee
    Jul 16
    Tuesday, next week, learn about app behavior review and build agents that run on your PRs with me and @xeonbloomfield. Sign up: clstk.com/4gGH0oq
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    Callstack Engineers
    @callstackio
    Jul 16
    Glad we could help on this one 🫡 Chat template formatting and issues with tool calling were small patches we needed to make for Apex, our React Native specialized model, to behave and perform better. Our team sent feedback, and Google Gemma team listened.
    user avatar
    Google Gemma
    Google for Developers
    @googlegemma
    Jul 15
    Replying to @googlegemma
    💬 Chat Template: Smoother conversational formatting. ⚙️ Tool Calling: Patched issues for accurate, consistent tool execution. (3/5)
    1.4K01.4K
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    Callstack Engineers
    @callstackio
    Jul 16
    Never heard of Apex? Read the blog post. We've onboarded a bunch of teams over the last month and will soon start inviting the 500+ engineers on the waitlist. Sign up if you haven't yet.↓
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    Introducing Apex: A Fast, Specialized Model for React Native
    From callstack.com
    2210221
  • Callstack Engineers reposted
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    Michał Pierzchała
    @thymikee
    Jul 15
    Gemma 4 improving model performance based on our team’s feedback was not on my bingo card
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    Piotr Miłkowski
    @xeonbloomfield
    Jul 15
    Replying to @googlegemma
    Thanks for the updates, and love that our feedback made it in! Now it's @callstackio's turn to cook - we're bringing these improvements into Apex, our React Native model built on Gemma 4: callstack.com/blog/introduci…
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  • Callstack Engineers reposted
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    Michał Pierzchała
    @thymikee
    Jul 15
    React Native Evals are out with a bunch of new models: → Sol only slightly better at 3x cost compared to Terra or Grok 4.5. → Muse Spark 1.1 feels like OpenAI's fourth model in terms of perf vs cost → Grok 4.5 scores 12 pp higher than Grok 4 at 4x less cost
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    Callstack Engineers
    @callstackio
    Jul 15
    AI-generated UI can look good in a demo and still create cleanup work in delivery. For one of our clients, we built a design-to-code workflow with enforced component usage and a visual QA loop, so generated screens had to match the source design before handoff. That helped the
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    Callstack Engineers
    @callstackio
    Jul 15
    Read the case study ➡️
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    Engineering AI Loops for a Cross-Platform Design System | Callstack
    From callstack.com
    2500250
  • user avatar
    Callstack Engineers
    @callstackio
    Jul 14
    A plausible PR is not the same thing as a safe release. If your review still stops at the diff, this webinar will show what is missing before the merge. Register to join @thymikee and @xeonbloomfield live on July 21 and see what that review loop can include, link below ⬇️
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    Callstack Engineers
    @callstackio
    Jul 14
    Register at
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    Behavior Review for AI-Native Delivery | Callstack
    From callstack.com
    3010301
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    Callstack Engineers
    @callstackio
    Jul 14
    Full house in Dubai. 🥳 Today we’re meeting for the OpenAI Codex Community Meetup, and we’re excited to spend the evening with a room full of builders working with Codex and coding agents. We’ll hear from Mike Grabowski (@grabbou) and Conor Spicer, make space for community show
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    Callstack Engineers
    @callstackio
    Jul 14
    More about the Meetup 👇
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    OpenAI Codex Community Meetup, Dubai | Callstack
    From callstack.com
    2220222
  • Callstack Engineers reposted
    user avatar
    Agent Conf | Sept 17-18, 2026 | Warsaw
    @AgentConf
    Jul 13
    Support AI adoption in your company by sending your engineers to Agent Conf. Two days on prompting, debugging agent behavior, multi-agent workflows, and adoption inside real teams. Use the promo codeTeams15 to get 15% off 3+ tickets. Get tickets: agent.sh/tickets
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  • Callstack Engineers reposted
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    Michał Pierzchała
    @thymikee
    Jul 11
    agent-device scores highest in this little benchmark, nice. there’s still so much we can do, we’ll keep on polishing the experience
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    Gabriel Moncha
    @gabimoncha
    Jul 11
    Replying to @gabimoncha
    gpt-5.6-sol high tried out the following: - argent by @swmansion - @agent_device by @callstackio - npx serve-sim by @Baconbrix - and the built in Build iOS apps action here is Sol's bench report with pros and cons
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    Callstack Engineers
    @callstackio
    Jul 10
    Native React Native debugging gets much easier once you ask where the work runs. Sync Turbo Module calls can hit the JS thread. Async calls move to the Turbo Modules thread. Fabric view updates stay on the main thread. That context saves time.
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    Callstack Engineers
    @callstackio
    Jul 10
    Grab your copy now:
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    Improve Your React Native App Performance With a Few Tricks | Callstack
    From callstack.com
    4700470
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REPLAY
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Callstack Engineers
@callstackio
How to Teach Your Own AI Model, Part 2: What Should You Build First?
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