Flutter vs React Native vs Kotlin Multiplatform: Which One Won't Destroy Your Sanity?

Flutter is Google's answer to "what if we just drew everything ourselves?" It uses the Skia graphics engine to render every single pixel, which means your app looks exactly the same on iPhone 6 and iPhone 15 Pro. That's great for design consistency, terrible for making iOS users feel at home.

The Reality: Hot reload works most of the time, until it doesn't and you're back to full restarts wondering why you didn't just write native. The infamous RenderFlex overflowed by 18 pixels error will haunt your dreams, and debugging Flutter web is like debugging with your eyes closed. Flutter 3.27 (December 2024) finally brought stateful hot reload to web, which helps, but web performance is still trash.

Flutter apps are chunky as hell - the framework adds 4-8MB to your app size because it has to include the entire rendering engine. Check out Flutter's performance best practices and app size optimization guide to minimize the damage. But hey, at least your loading spinner looks identical on every platform.

When it breaks: "Have you tried turning it off and on again?" becomes your mantra. `flutter clean && flutter pub get && flutter run` fixes 90% of weird issues. Check the Flutter GitHub issues for the other 10%.

React Native: JavaScript Everywhere (Even Where It Shouldn't Be)

React Native lets you use JavaScript to control actual native UI components through a bridge. If your team knows React, this sounds amazing. If they don't, prepare for some learning curves.

The Reality: Metro bundler crashes more often than Windows ME, and the 'could not connect to development server' error shows up for literally no reason - usually when you're demoing to stakeholders. Android and iOS builds break differently for the same code, and upgrading React Native versions is basically Russian roulette.

The New Architecture with Fabric and TurboModules is supposed to fix performance issues, but migrating feels like performing surgery on a moving patient. React Native 0.76 (October 2024) finally enabled the New Architecture by default, which means fewer bridge bottlenecks but more migration headaches for existing apps.

When it breaks: Clear Metro cache, restart the bundler, sacrifice a goat to the JavaScript gods. In that order.

npx react-native start --reset-cache
## The nuclear option when nothing else works

Kotlin Multiplatform: Share Logic, Debug Twice

Kotlin Multiplatform promises to let you share business logic while keeping native UIs. In theory, this is brilliant. In practice, you're debugging the same bug in three different IDEs.

The Reality: Setting up iOS compilation on Windows is basically impossible. The documentation is scattered across 47 different websites. You still need to know Swift/Objective-C for iOS-specific stuff, and "business logic sharing" sounds great until you hit platform-specific edge cases. Kotlin 2.1 (November 2024) introduced basic Swift export support, but it's still experimental and you'll probably break something trying to use it.

Netflix, Cash App, and other major companies use it, which is encouraging, but they also have teams of people whose full-time job is making this stuff work.

When it breaks: Good luck. You're debugging Kotlin compilation to Objective-C that gets compiled to ARM64. The error messages are about as helpful as a null pointer exception.

Architecture: KMP compiles your Kotlin business logic to native code for each platform, while UI stays completely native.

Bottom Line: Pick Flutter if you want everything to look the same everywhere and don't mind fighting iOS design guidelines. Pick React Native if your team already knows JavaScript and React, and you can tolerate Metro crashes. Pick Kotlin Multiplatform if you have complex business logic to share, senior mobile devs, and a high tolerance for setup pain - or if you're Netflix with unlimited engineering resources.

The choice ultimately comes down to what pain you're willing to accept: Flutter's platform integration headaches, React Native's JavaScript bridge quirks, or KMP's complexity tax.

Those comparison tables are nice, but they don't capture the 3am debugging sessions or the moment your stakeholder demo crashes.

After building production apps with all three frameworks, here's the shit nobody tells you in the tutorials

• the real experiences that determine whether you'll recommend a framework or warn people away from it.

Flutter: Great Until You Need to Feel Native

Flutter is perfect for MVPs and startups that need to move fast and look consistent.

I built a fintech app that needed to look identical on every device

• Flutter nailed it. The design team loved that their mockups translated perfectly to code.

Where it shines:

• Design-heavy apps where pixel-perfect consistency matters
• Teams with limited mobile experience (easier learning curve than going native)
• Rapid prototyping when you need to validate ideas quickly

Where it falls apart:

• iOS users immediately notice it doesn't feel like an iOS app.

The scrolling physics, the animations, the little details

• they're all slightly off
• Flutter web performance is absolute trash.

I learned this the hard way when the marketing team wanted a web version

• Deep platform integrations are painful. Want to access the iOS camera API directly?

Good luck with that

• Check Flutter's platform integration docs to understand the limitations

I spent two weeks trying to make Flutter follow iOS design guidelines for a banking app.

The client kept saying "it doesn't feel right" and pointing at other iOS apps saying "why can't ours scroll like that?"

React Native:

Java

Script Saves the Day (Until It Doesn't)

React Native is the Swiss Army knife of mobile development. If your team knows React, they can be productive immediately. I've seen web developers shipping mobile features in their first week.

The good news:

• Massive npm ecosystem
• if you need it, someone's probably built it
• Native UI components mean users feel at home on their platform
• Hot reloading when it works (and it works most of the time)
• The new architecture actually fixes a lot of the bridge performance issues
• Great debugging tools including Chrome DevTools integration

The painful reality:

• Metro bundler has a personal vendetta against developers.

It crashes, it caches things it shouldn't, it doesn't cache things it should

• Upgrading versions is like playing Jenga blindfolded.

Something always breaks

• Bridge performance can be brutal for data-heavy apps. Check the performance docs before you hit the 1000+ item wall
• I had to rewrite our list rendering in native code because scrolling was janky with 1000+ items

Production horror story: Spent three days debugging why our Android builds were failing in CI but worked perfectly on every developer's machine.

Turned out to be a Metro cache issue that only manifested in fresh Docker containers

• because of course it was.

Kotlin Multiplatform:

The Enterprise Darling

KMP is the framework for teams that already have native mobile expertise and want to share business logic. Netflix proves it works at scale, but Netflix has engineering resources that most of us can only dream about.

Why enterprises love it:

• You get true native performance with shared business logic
• Gradual adoption means you're not rewriting everything at once
• Your i

OS app still feels like an iOS app, your Android app feels like Android

• Type safety across platforms reduces bugs

Why normal teams struggle:

• Setup complexity is brutal.

Getting i

OS compilation working on anything but a Mac is a nightmare

• You need expertise in Android Studio, Xcode, AND IntelliJ IDEA
• Documentation is scattered across multiple websites and often outdated
• Debugging shared code that runs on different platforms is an exercise in masochism

When it's worth it: If you have complex business logic that needs to be identical across platforms (financial calculations, game logic, data processing), and you have senior developers who won't quit when the setup gets complicated.

The complexity reality: KMP project structure involves shared modules, platform-specific modules, and build scripts that make Gradle look simple.

The Honest Decision Matrix

Pick Flutter if:

• Your design team cares more about consistency than platform conventions
• You're building an MVP and need to move fast
• Your team is new to mobile development

Pick React Native if:

• Your team knows React and JavaScript
• You want native-feeling UIs without the complexity
• You need to ship features quickly and don't mind debugging Metro crashes

Pick Kotlin Multiplatform if:

• You have senior mobile developers who won't rage quit
• You have complex business logic that benefits from sharing
• You're building enterprise software and can afford the setup complexity
• Performance is critical and you can't accept any compromise

Don't pick any of them if:

• Your app is simple enough that maintaining two native codebases isn't a big deal
• You need bleeding-edge platform features immediately
• Your team is small and doesn't have time for cross-platform complexity

These real-world experiences shaped how I answer the questions developers actually ask when they're trying to make this decision. The marketing materials won't tell you about Metro crashes or Render

Flex overflow errors, but these are the realities that determine whether you'll love or hate your framework choice six months from now.