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- 5xfaster message sending timeExpensify
- 10min from code change to mini-app releaseTeamworks
- -28%CPU usage in critical trading flowsQuestrade
- 2×Estimated AI-assisted delivery speedup
- 25Working days from kickoff to merge
- 1Plugin across three frameworks
- 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
- 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
- 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
- 4.5xfaster search screen loading timeExpensify
- #1SEO rank, recovering from 3-9AutoZone
- 260kBless in blocking JS payloadAutoZone
- 2–5xfaster feedback loopAutoZone
- 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
- 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
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Clients
Trusted by enterprise teams at scale.
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.
Their engineers proved to be a crucial part of our mobile app relaunch project.
The trainers are always very helpful and supportive. It really makes a difference!
I appreciate their attention to detail, flexible approach and a high degree of expertise.
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We had been struggling with React Native application performance until we met Callstack.
I recommend them as a trusted tech partner for running complex projects.
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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Wrocław HQ
Prosta 3653-508 Wrocław, Poland
Vienna / Margelo
Barichgasse 38/3.51030 Vienna, Austria
San Francisco
945 Market StreetSan Francisco
CA 94103, US
