Flutter custom notifications

Every Flutter app needs notifications. Whether it's a success alert after a payment, an error toast when upload fails, or a warning banner before a session expires — you need them everywhere. Most developers reach for ScaffoldMessenger.showSnackBar() and call it a day. But after building several production apps, I found this approach too limiting. So I built a proper reusable notification system from scratch. Here's everything I learned. The Problem with ScaffoldMessenger ScaffoldMessenger works for basic cases but has real limitations: Tied to Scaffold context — breaks in certain widget trees Very limited customization (position, style, animations) Can't easily show dialogs AND toasts simultaneously No built-in dark mode support Animations are not customizable The Solution — Flutter's Overlay API Overlay is Flutter's built-in system for showing widgets above everything else — it's literally how tooltips, dropdowns, and route transitions work internally. Here's the core pattern: dartvo