Is migrating to Dart's Null Safety worth the effort for large Flutter apps, or just a cosmetic update?

Many teams wonder if the breaking migration to null safety delivers real ROI in terms of code safety and performance or if it’s just extra burden.

A: Dart’s Null Safety (introduced circa Dart 2.12/Flutter 2) is far more than cosmetic. It provides: • Compile-time null-uncheckable guarantee, eliminating NullPointerException at runtime. • Fewer ? checks, more readable code, stronger static analysis. • Performance gains, because the compiler can optimize memory layout and AOT code paths (no null-check repeaters or type guards at runtime). • Starter tooling: dart migrate helps partially migrate. According to developer reports migrating even 200k+ line apps, they found bugs during the process that had gone unnoticed, refactored code with fewer null-checks, and improved maintainability. Transition tooling may cover only about 25% of cases—manual cleanup remains necessary—but the result is much cleaner, safer code. With null safety, teams can use newer packages without compatibility issues. Overall: for any evolving app (or one trying to onboard new Flutter only dependencies), migration to null safety is definitely worth it.

Tags: Flutter, Dart null safety, migration, performance, code quality