Optimize performance of your React Native application
From startup speed to UI responsiveness, we help teams identify and eliminate bottlenecks in their React Native apps—without rewriting them.
Why you should optimize performance of your React Native application
Users expect instant interactions—anything less leads to churn, lower app ratings, and lost revenue. Performance optimization isn’t just about speed; it’s about business outcomes.
Users uninstall slow apps
Over half of users will uninstall an app that takes more than 3 seconds to launch—startup time directly impacts retention.
Users uninstall slow apps
Over half of users will uninstall an app that takes more than 3 seconds to launch—startup time directly impacts retention.
Users stay active after 30 days
Apps with better performance see stronger retention and lower churn—smooth experiences keep users coming back.
Users stay active after 30 days
Apps with better performance see stronger retention and lower churn—smooth experiences keep users coming back.
Expectations are higher for native apps
Users expect better speed and reliability from mobile apps compared to mobile websites—slow apps break that trust.
Expectations are higher for native apps
Users expect better speed and reliability from mobile apps compared to mobile websites—slow apps break that trust.
Expensify made their app 3× faster with Callstack’s help
Together with Expensify, we performed a series of performance measurements across their most critical components. After identifying KPIs and areas for improvement, we optimized their core flows—reducing startup times and message latency while improving overall UX on both iOS and Android.
3x
Faster startup time
6x
Less time to send a message
What are the performance bottlenecks to look out for?
Even high-quality apps can have performance bottlenecks that go unnoticed until users start leaving. Here are the most common issues we find in production React Native apps.
Scrolling performance
As the app grows, unnecessary dependencies and unoptimized initialization logic can slow down cold starts—hurting first impressions.
Time to Interactive (TTI)
Expensive re-renders and unbatched state updates delay Time to Interactive (TTI), making apps unresponsive even after launch.
Choppy animations
Janky transitions and laggy gestures are often caused by blocking operations on the JS thread or layout recalculations.
High memory consumption
Unused listeners, unmounted screens, and memory leaks can cause device-level performance issues—especially on older devices.
Bundle size
Oversized JavaScript bundles lead to slower startup and increased parsing time. Tree-shaking and code splitting can dramatically improve load time.
Low-end devices
Many teams optimize for flagship phones. But users on older or low-spec devices often suffer the most from unoptimized code.
Catch performance regressions real-time with our Open Source library
Reassure is a performance testing library for React Native that helps you detect UI regressions at the component level. By comparing render durations between versions, it ensures performance stays consistent—especially after refactors or updates.
- Component-level render measurement with statistical diffing to highlight meaningful performance changes
- First-class CI support with auto-generated scripts for popular providers
- Flexible APIs to measure render time, sync/async functions, and define custom interaction scenarios
Make your React Native app feel fast, smooth, and native
Optimize your React Native app performance
We analyze critical paths—startup time, UI responsiveness, thread load, and memory—to deliver concrete improvements users will feel. From smoother animations to faster screens, we help your app feel native.
Identify performance issues in your React Native application
We profile your app across JS and native layers to uncover hidden bottlenecks, excessive re-renders, blocking operations, or inefficient component trees—then prioritize what’s worth fixing.
Setup CI/CD pipeline to catch bugs and prevent regressions in real-time
We integrate performance checks into your existing CI/CD pipeline, helping you track startup time, TTI, and frame drops over time—and stop regressions before they reach production.
Get performance audit for your React Native application!
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.
Team at scale
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.
FAQs
Performance work raises a lot of questions—technical, strategic, and practical. Here are answers to the most common ones, so you know exactly what to expect when working with us.
Performance problems aren't always obvious in development. If you see slow startup, janky animations, dropped frames, high memory use, or poor retention metrics, it's likely your app needs optimization. We use profiling tools to identify and validate these issues with real data.
Not necessarily. Most improvements come from optimizing rendering patterns, bundling, and resource handling—without rewriting core features. In brownfield or legacy apps, we focus on targeted improvements that deliver results without disrupting existing workflows.
We assess startup time, UI responsiveness, memory usage, JS thread pressure, and bundle size. The audit includes a detailed report with key findings, prioritized recommendations, and potential impact estimates.
Yes. We offer hands-on implementation, advisory support, or can work embedded with your team. Our engineers apply fixes directly or help your team ship them safely.
No. We work alongside your existing release process and can integrate performance monitoring directly into CI to help you catch regressions without slowing down delivery.
We use a mix of open-source tools (like Reassure), platform-specific profilers (Flipper, Xcode Instruments, Android Profiler), and custom scripts tailored to your app architecture.
While results vary, teams typically see faster startup, smoother UI, reduced crash rates, and better retention—especially on low-end devices. All improvements are measurable, and we help you track them before and after implementation.
Need help with React Native performance?
Whether you've spotted specific bottlenecks or just know your app could run better, we’ll help you identify the root causes and fix what matters—fast.
