Dart

Developers hardcode API keys in Dart code (trivially extractable), omit certificate pinning (vulnerable to MITM), store user data unencrypted, and ignore GDPR/CCPA/HIPAA compliance requirements. Security is often an afterthought until it's too late.

Without discipline, larger Flutter projects devolve into architectural horror shows with God classes containing thousands of lines, circular dependencies, business logic mixed into widgets, and zero separation of concerns. This makes maintenance and changes extremely difficult.

Controllers and streams (AnimationController, TextEditingController, ScrollController, FocusNode, StreamSubscription) allocate resources that Dart's garbage collector doesn't automatically clean up. If not manually disposed, they remain in memory after their widgets are destroyed, causing memory leaks in long-running apps.

Flutter apps depend heavily on async operations (network calls, file I/O, streaming), but developers frequently fail to properly handle errors, update widget states incorrectly, or mismanage async calls. This results in unhandled exceptions, race conditions, and broken UI states.

Dart is not widely adopted compared to JavaScript, Kotlin, or Swift, making it challenging to recruit experienced Flutter developers and often requiring organizations to retrain existing teams. The smaller developer community also means fewer learning resources and solutions for debugging complex issues.

Developers must maintain two distinct ecosystems (e.g., Dart for UI and Elixir for backend) simultaneously, creating unsustainable cognitive load and full-stack fatigue, especially for smaller teams or individual developers.

The Dart team cancelled the macros feature after determining performance issues and high compile-time costs were too expensive to solve reasonably. Developers interested in metaprogramming capabilities have no near-term solution.