Feature Development

Ship priority features with React and React Native experts.

Senior product engineers join your team to clear backlog, ship roadmap work, and take high-impact implementation off your internal leads. AI-native delivery lets a small expert team cover more ground without lowering your bar for review, testing, or architecture.

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Trusted by 100+ Enterprise clients

Why ship with Callstack

Ship more without adding a team.

Senior product engineers bring the specialist knowledge your roadmap needs. They join your existing team to tackle demanding features, own implementation, and share their expertise as they work.

  • Access specialist expertise when you need it.

    Bring in deep knowledge of framework internals, native integrations, and performance to unblock technically demanding features.

  • Get more done with a smaller team.

    AI-native workflows increase output across implementation, testing, and cleanup, so delivery grows without headcount growing linearly.

  • Raise the team's bar while we work.

    Daily collaboration with senior engineers and core contributors gives your team better patterns it keeps after the engagement.

Services

Choose the capabilities your roadmap needs.

  • Stacks

  • React Native Development

    Build native iOS, Android, TV, and desktop apps from one codebase, with native performance and UX and without maintaining a separate team per platform.

  • React Development

    The UI library powering most of the modern web. A proven foundation for building product interfaces that stay fast and maintainable as they grow.

  • Next.js Development

    The production-grade React framework with server rendering, streaming, and edge delivery. Ship fast sites that stay fast as traffic and scope scale.

  • Expo Development

    The fastest path from idea to shipped React Native app. Managed builds, OTA updates, and a runtime that removes weeks of native tooling work.

  • Node.js Development

    One language across frontend, backend, and tooling. Teams ship faster when the API, app, and automation all run on the same runtime and skill set.

  • C++ Development

    The language behind performance-critical native work. Graphics, media, real-time processing, and the native modules that sit under every demanding mobile app.

  • Module Federation Development

    Load independently built and deployed JavaScript bundles into one running app, sharing code and dependencies between them at runtime.

  • On-Device AI

    Run models directly on user devices for privacy, offline use, and low-latency experiences without a cloud round-trip.

  • Design

  • Feature UX/UI Design

    Design flows, screens, states, and interactions for roadmap features before implementation starts, so engineering ships UI that is clear, feasible, and production-ready.

  • Cross-Platform Design Systems

    Build one system of tokens, components, states, and patterns that works across every platform.

Feature Development

Start with a codebase review.

Give us 60 minutes in your repo. We'll come back with what a senior AI-native team would prioritize and how we'd staff it.

Book a call

How we work together

Turn roadmap scope into shipped features.

  • Extend your team

    Our senior engineers join your team to ship features, guide technical decisions, and strengthen delivery.

    • Your roadmap and workflow
    • Expertise shared as we work
    • Flexible timezone coverage

  • Deliver a project

    We take agreed work from technical planning to release, with clear responsibilities and progress you can see.

    • 3 Callstack engineers ship like 6
    • Impact visible before sprint two
    • End-to-end delivery

  • Solve specific challenge

    We address a performance, migration, or infrastructure challenge, or run training around your team’s needs.

    • Focused reviews or implementation
    • Knowledge your team keeps
    • Outcomes guaranteed with contract
React Foundation Founding Member
300+ commits to React Native
100+
Enterprise projects delivered
Industry runs on our tooling
50M+
OSS downloads / month
3.7×
Lower task cost vs Opus 5.5
With the release of Re.Pack 5 we now have an easy way to create the MiniApps and federated mobile apps that our users have been asking for.
Zackary Chapple
CEO / Zephyr Cloud
~6x
Faster prototyping
60+
Components mapped with full coverage
React Native Paper

A component library in our open-source toolkit for building React Native interfaces.

10 years of React Native → Now in your AI stack

Start with a codebase review.

Give us 60 minutes in your repo. We'll come back with what a senior AI-native team would prioritize and how we'd staff it.

Book a call

Open Source

Build with our open-source tools.

We open-source the tools behind our delivery model.
Use them, fork them, or let us run them for you.

Check All ToolsExplore AI Infrastructure

React Native Paper

Material Design for React Native (Android & iOS)

2M downloads/mo

React Native Bottom Tabs

Native Bottom Tabs for React Native

408.8K downloads/mo

React Navigation

Routing and navigation for your React Native apps

218.4K downloads/mo

Liquid Glass

iOS Liquid Glass in React Native

539.2K downloads/mo

Voltra

Voltra lets React Native developers build native iOS Live Activities, Dynamic Island layouts, and widgets as React components without writing Swift.

88.1K downloads/mo

Linaria

Zero-runtime CSS in JS library

12.4K stars

React Native Vision OS

A framework for building native visionOS applications using React Native

1.1K stars

Insights

Worth your time, by engineers.

Explore Insights
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Oct 15Article

Multi-Window React Native Apps With the Meta VR Layout SDK

Add a second Quest window to your existing React Native tree without creating another Android activity. Follow a Meta VR Layout SDK companion-panel demo covering setup, shared state, window positioning, fallbacks, and testing with Meta Spatial Simulator.

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Oct 7Talk

How To Build a Plugin Framework by Hacking React Native DevTools

Szymon Chmal explains how he built Rozenite, a plugin framework for React Native DevTools, and shows what developers can create with it.

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Jul 7Podcast

Where Reanimated Goes Next

A conversation with Bartłomiej Błoniarz on CSS animations in Reanimated, native primitives on iOS, shared element transitions, and the work still left on stability.

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Jul 2Article

Mobile Module Federation with Re.Pack: When Runtime Delivery Is Worth the Complexity

This article explains what Module Federation means in React Native and how Re.Pack brings runtime-loaded JavaScript modules to mobile apps. It shows where this architecture can help, where packages or code splitting are the better choice, and what teams need to validate before adopting it in production.

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Jun 29Article

Less Boilerplate, More Type Safety: React Navigation 8's Typed Hooks

React Navigation 8 makes typed hooks much more useful in day-to-day TypeScript work. Passing a screen name to useRoute, useNavigation, or useNavigationState gives you more specific types, cleaner route.params, and fewer unsafe casts or bulky composite types. This article breaks down what changed and where the improvements pay off most.

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Apr 30Live Stream

Build a React Native App With the TanStack Stack

Join Callstack’s live stream on building a React Native app from the ground up using the TanStack toolbelt.

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Mar 26Live Stream

Expo UI with SwiftUI and Jetpack Compose in practice

Exploring Expo UI with SwiftUI and Jetpack Compose, including setup challenges, architecture tradeoffs, and real-world developer insights.

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Mar 5Article

Keeping Screens Visible With <Activity mode="hidden">

`<Activity mode="hidden">` can reduce unnecessary work by unmounting effects for inactive UI trees. But it also hides the UI with `display: none`, which causes issues for gesture‑driven navigation. This article explores a workaround that keeps screens visible while still freezing effects across native and web.