We have built 40+ mobile apps. Here are the mistakes that kill cross-platform projects before launch. By David Friedman , Founder of AppBrewers Cross-platform development promises write once, run everywhere. The reality is more nuanced. Here is what we have learned building React Native and Flutter apps for startups. Mistake #1: Choosing Based on Hype Flutter is Google-backed. React Native is Facebook-backed. Both are excellent. The right choice depends on your team, not the framework's popularity. Choose React Native if: You have React web developers, need fast iteration, or want Expo's ecosystem. Choose Flutter if: You need pixel-perfect UI, complex animations, or plan to target desktop/web later. Mistake #2: Ignoring Platform Differences Cross-platform does not mean identical. iOS and Android have different navigation patterns, permissions, and design guidelines.…