100+ Enterprise Clients
7B+ active clients users
$1.8T Clients Revenue
From startups to Fortune 500.
From React Native migrations to AI-native delivery infrastructure, these are the products, platforms, and engineering systems we helped teams move forward.
We unified the bank’s React Native codebase and improved CI/CD, automated testing, and diagnostics to address integration issues that were delaying mobile releases. The time from feature completion to release readiness fell from 19 to 14 days. Feature teams gained earlier feedback, while the Platform Team took greater ownership of delivery.
- 26%
- less time preparing releases
- 30
- minutes to make a fix testable
- 45
- automated integration checks
- 33%
- fewer re-renders across most features
- 3→1
- analytics systems unified into a single interface
We built a first-class Storybook integration for WebStorm that combines an IDE-native workspace with AI-assisted story generation across React, Vue, and Angular.
- 2×
- Estimated AI-assisted delivery speedup
- 25
- Working days from kickoff to merge
- 1
- Plugin across three frameworks
- 10
- min from code change to mini-app release
- 2x
- growth in mobile user base during the migration period
We introduced native build reuse and signed delivery for compatible micro-frontends in a Southeast Asian bank’s React Native app with 15M+ registered users, preserving security checks. Full-cache-hit tests cut Android build time by 79% and the measured iOS flow by 58.3%. In an illustrative model of 40,000 annual cache-hit builds split evenly across Android and iOS, the avoided runtime is valued at around US$30,000 using public CI rates.
- 2.4×
- faster iOS cache-hit builds on average
- 2×
- faster Android builds with partial reuse
- 82%
- smaller CI installation footprint
MoMo successfully migrated its platform and mini apps to a new architecture using Re.Pack, boosting performance and scalability.
- 6x
- faster builds after replacing Jenkins with EAS
We used an agentic SDLC to deliver a production-ready web platform in under one month, with agents executing an estimated 80% of the development effort.
- 3x
- estimated delivery acceleration
- 80%
- of dev effort executed by agents
- 95+
- desktop Lighthouse performance
- 5
- platforms under one RN codebase: tvOS, FireTV, Tizen, LG, Vizio
- 78%
- bundle size reduction (from 50 MB to 11 MB)
We helped an enterprise software team, with an initial rollout spanning 30+ engineers, turn Figma designs into production-ready code faster, with more consistent UI and built-in quality checks across web and mobile.
- 60+
- components mapped with full Code Connect coverage
- ~6x
- faster prototyping for a typical enterprise screen
- <2%
- visual diff threshold for generated screens
- 100k
- weekly downloads on npm
We partnered with Expo to enable instant prototyping, real-device preview, and easy sharing of React Native projects, all without local setup.
Discover how we revamped the Expensify app for lightning-fast experiences, guided by a systematic DMAIC approach.
- 5x
- faster message sending time
- 4.5x
- faster search screen loading time
- #1
- SEO rank, recovering from 3-9
- 2.8x
- increase in knowledge over 8 weeks (25% → 71% assessment scores)
We rebuilt the React Native integration and release architecture behind a large crypto trading platform used by millions of people. Native artifacts, a monorepo, fingerprint-based OTA, and AI-assisted workflows gave product teams a controlled way to move more screens to React Native while continuing to ship features.
- 4x
- increase in RN pages across the tracked page set
- 30%
- React Native adoption reached during the migration
- Millions
- MAUs covered by the production-ready OTA model
- 130%
- increase in users post-upgrade
- 5%
- faster startup time on FireTV and FireHD devices
- 63%
- adoption rate; majority of attendees registered in the app
We integrated ZephyrCloud with React Native and developed a white-label application to showcase Zephyr features as well as provide easy getting started story.
From strategy to infrastructure
Everything you need to ship at AI speed
Build your product with senior React and React Native engineers, or improve delivery with an agentic SDLC.
Expert engineering
Build and scale React Native apps.
Agentic Delivery
Turn AI into better software delivery.
Clients
Trusted by enterprise teams at scale.
Teamworks needed Module Federation, we helped make it real
Not only does Callstack have tremendously talented engineers, but I know they care about the success of the project as much as I do.
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We had been struggling with React Native application performance until we met Callstack.
I appreciate their attention to detail, flexible approach and a high degree of expertise.
The trainers are always very helpful and supportive. It really makes a difference!
I recommend them as a trusted tech partner for running complex projects.
Their engineers proved to be a crucial part of our mobile app relaunch project.
The team at Callstack are the most experienced engineers in the React Native community.
If you're looking for skilled and trusted React Native developers, Callstack is definitely the way to go.
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- 10min from code change to mini-app releaseTeamworks
- multi-dailystaging deployments instead of weekly releasesTeamworks
- 7mini-apps supported in one modular mobile platformTeamworks
- 2CI/CD lanes for mini-app and host-app distributionTeamworks
- 2×Estimated AI-assisted delivery speedup
- 25Working days from kickoff to merge
- 1Plugin across three frameworks
- 5xfaster message sending timeExpensify
- 4.5xfaster search screen loading timeExpensify
- 78%bundle size reduction (from 50 MB to 11 MB)Dream11
- 30%faster component mount time after render optimizationDream11
- 60%faster initial load time enabled by switching to HermesDream11
- 2xgrowth in mobile user base during the migration periodAutoZone
- 4.2 -> 4.7app rating increase after migrating to React NativeAutoZone
- 0missed releases during the transition to React NativeAutoZone
- 33%fewer re-renders across most featuresQuestrade
- 18%faster time-to-interactiveQuestrade
- -28%CPU usage in critical trading flowsQuestrade
- #1SEO rank, recovering from 3-9AutoZone
- 260kBless in blocking JS payloadAutoZone
- 2–5xfaster feedback loopAutoZone
- 130%increase in users post-upgrade
- 63%adoption rate; majority of attendees registered in the appReact Universe App
- 67%of attendees connected through QR badge sharingReact Universe App
- 45%created personalized badges to showcase identity and goalsReact Universe App
- 49%of attendees onboarded before day one, arriving ready to networkReact Universe App
- 2.8xincrease in knowledge over 8 weeks (25% → 71% assessment scores)Hello Fresh
- 15developers trained across web and native backgroundsHello Fresh
- 86%of devs self-rated their knowledge as 3/5 or higher after training (up from 0%)Hello Fresh
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