How We Cut Our Flutter App Size by 40% (Without Removing Any Features)
One question I hear a lot from teams is: "How can we reduce our Flutter app size without losing anything?"
Here's the exact checklist we used to shrink our app from 52 MB down to 31 MB — and we didn't remove a single feature.
1. Remove Debug Symbols
Debug symbols are essential during development, but they bloat your production builds unnecessarily.
This separates debug information into a different directory, keeping your APK lean while still allowing crash analysis when needed.
2. Optimize Assets
Assets often take up the most space in mobile apps. A little cleanup goes a long way.
What we did:
- Compressed images using tools like TinyPNG or ImageOptim
- Removed unused files from the assets folder
pubspec.yaml to ensure you're not bundling assets you don't actually use.
3. Tree-Shaking & Code Cleanup
Flutter's release mode automatically removes unused code, but you can take it further.
Additional step:
Use Flutter DevTools to identify and clean up unused code manually.
This helps eliminate dead imports, redundant widgets, and unused dependencies.
4. Import Only What You Need
Avoid pulling in large packages when you only need a small feature.
Common example: Firebase 👀
Instead of importing the entire Firebase suite, import only the specific modules you need:
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_storage/firebase_storage.dart';
// ✅ Do this - only what you actually use
import 'package:firebase_auth/firebase_auth.dart';
Every unnecessary package adds weight. Be selective.
5. Split by ABI
Android devices run on different CPU architectures (ARM, x86, etc.). Instead of bundling all of them into one APK, create device-specific builds.
Users only download what their device needs.
✅ Final Result
40% reduction
No hacks. No feature cuts. Just smart optimization.
Key Takeaways
- Debug symbols can be separated to save ~8 MB
- Asset optimization is low-hanging fruit (10-12 MB saved)
- Tree-shaking removes dead code automatically in release mode
- Be selective with package imports
- Split APKs by ABI for device-specific builds
Give these steps a try on your Flutter app and watch the size drop. Your users (and their storage space) will thank you.
