
Reuse native code through typed React Native.
Type-safe npm package
Your library wrapped in a documented JS module with full TypeScript types. Use it like any dependency.
Keep native performance
Native code stays fast and memory-light for compute-heavy work, no JS rewrite, no new bugs.
One integration, every platform
Works across iOS, Android, web, TV, and even VR/AR from a single wrapper.
Bridgeless architecture
Built on React Native's New Architecture for faster calls and simpler long-term maintenance.
Performance instrumentation
Built-in monitoring so you can verify the library performs in the mobile context, not just on paper.
Docs and upgrade paths
Maintenance guidelines and clear update paths, so your team extends the integration over time.
Scope → Build → Scale
Turn technical limits into shipped fixes.
Scope
We map your problem, align on deliverables, and define success metrics. No surprises once work starts.
Build
Engineers ship with AI-native workflows from sprint one. Code, decisions, and ownership, not discovery decks.
Scale
Expand scope, add platforms, or hand off to your team. The stack, tooling, and raised bar stay with you.
Case studies
What shipping at AI speed looks like
Why teams bet on Callstack
From billion-user apps to React Native core, this is why teams choose Callstack when they need to move fast and get it right.

10 years in React Native. Now shaping agentic engineering.
For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.
Founded in 2016 ·Backed by Viking Global Investors
React Foundation members. Core Contributors.
We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.
Open source since 2016. Our code runs in your app.
We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.
39M+
Downloads / month67K+
GitHub stars300+
React Native commits100+ Enterprise clients with 7B+ users.
We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.


































Agent Conf. The conference for the Agentic era.
The conference we built for the shift from writing code to orchestrating agents.


We are Codex Ambassadors.
We run meetups, workshops, and hands-on sessions that help teams learn Codex and apply it in real work.

10 years in React Native. Now shaping agentic engineering.
For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.
Founded in 2016 ·Backed by Viking Global Investors
React Foundation members. Core Contributors.
We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.
Open source since 2016. Our code runs in your app.
We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.
39M+
Downloads / month67K+
GitHub stars300+
React Native commits100+ Enterprise clients with 7B+ users.
We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.


































Agent Conf. The conference for the Agentic era.
The conference we built for the shift from writing code to orchestrating agents.


We are Codex Ambassadors.
We run meetups, workshops, and hands-on sessions that help teams learn Codex and apply it in real work.
Let’s find the right path for your product.
Whether you’re planning new work or unblocking an existing product, we’ll help you choose the right path forward.
Which languages and libraries do you support?
Any C-compatible library, including C, C++, Golang, Rust, and others that expose a C ABI.
Will the integration work with React Native's new architecture?
Yes. We build integrations using bridgeless, new-architecture patterns for better performance and maintainability.
How long does an integration typically take?
Weeks, not months. Exact timing depends on your library complexity and target platforms.
Can I use the same library on web?
Often, yes. If your library can compile to WebAssembly or has a web-compatible build, we can support web alongside mobile.
What about updates to the original library?
We design integrations to make version updates straightforward, with clear upgrade paths.
Do you support older React Native versions?
We recommend the new architecture, but can support older versions if your project requires it.
Will you rewrite our native library in JavaScript?
No. We wrap your existing native library and expose it safely to React Native.
How do you confirm the library performs well on mobile?
We add built-in performance instrumentation, so you can verify the library performs in the mobile context, not just on paper.
Bring your native library into RN
Tell us the language and library. We'll wrap it with full type safety and New Architecture support, in weeks.
We had been struggling with React Native application performance until we met Callstack.
Open Source
Want to build it on your own?
We open-source the tools behind our delivery model.
Use them, fork them, or let us run them for you.
Insights















































































































