TL;DR The native code is rarely the hard part of a Flutter plugin. The hard parts are: lifecycle correctness across both iOS and Android, permission flows, async cancellation, supporting users who file half-formed issues, and shipping breaking changes without breaking the world. A successful plugin costs 4 to 8 engineer-weeks before launch and a few hours per month forever after. The plugin in numbers Metric Value pub.dev likes 156 pub points 130 Monthly downloads 470 In production 5+ years The plugin in one paragraph document_scanner_flutter is a cross-platform Flutter plugin that lets an app capture a photo of a document, auto-detect the paper edges, perform perspective correction, and return the cropped, rectified image. It uses Apple Vision on iOS and Google ML Kit on Android. Apps using it include KYC flows, expense reporting tools, and field-data collection apps. The architecture, layer by layer A Flutter plugin lives at the edge between the Dart VM and the native platform.…