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AI ENGINEERING

Ship production-ready AI across platforms

Design, build, and scale AI-powered systems that run reliably in production. From on-device intelligence to generative experiences, we help teams ship AI that performs under real conditions.

on-DEVICE AI

Run AI models directly on iOS and Android for privacy-first experiences with reliable performance across real devices.

AI Knowledge Integration

Connect AI to your product’s knowledge so answers stay accurate, up to date, and backed by the right sources with proper access control.

Generative AI App Development

Build and ship production-ready AI features across iOS, Android, and Web with reliable UX, safety controls, and observability.

AI Vibe Coding Cleanup

Turn AI-generated code from tools like Cursor, Claude Code, Codex, or Replit into production-ready software by tightening structure, validating safety, and making it stable under real-world usage.

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Case studies

We solve real-world challenges with
React and React Native

Take a look at the projects we did for enterprises and small businesses. We can help your company grow as well.

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Trusted by world's leading companies

Why leading companies work with Callstack

Meta Official Partners

We are official Meta partner for React Native, co-organizers of React Conf and hosts of React Universe Conf.

Working at scale

We know how to make React Native work at enterprise scale, both technically and organizationally.

React Native Core Contributors

We don’t just use React Native to build cross-platform apps, we help shape it for millions of developers.

Always ready to start

We’re a team of 200+ engineers ready to start fast and scale with your needs.

Enterprise-friendly

We hold ISO certifications and follow strict security standards to make onboarding smooth and compliant.

Wide range of services

As a partner for your full application lifecycle, we offer a full range of services around React and React Native.

We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
We don't follow best practices, we set them
React Native Core Contributors
Trusted by Meta, Microsoft, and the community
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Hire us

Looking for something else?

We build custom solutions for unique needs. If yours is not on the list, drop us a message, we’ll take it from there.

We’ve helped dozens of teams go cross-platform without rewriting everything. Let's see how we can help you.

Mike Grabowski
CTO & FOUNDER
@
Callstack