My Flutter-based POS application needs a fully embedded printing module that talks directly to ESC/POS thermal printers—no RawBT or third-party bridges. The goal is a seamless “print” button that just works, whether the user plugs in a USB cable, pairs over Bluetooth, joins the same Wi-Fi/LAN, or uses AIDL on an Android POS terminal. What has to happen • A settings page inside the app where users can search for nearby printers, view connection details, and save multiple profiles. • Stable output to 58 mm and 80 mm printers for text, logos, barcodes, QR codes, and full-page PDFs. • Support for Bluetooth, USB, Wi-Fi/Ethernet, and the AIDL interface many Android POS devices expose. • Raw, low-level ESC/POS commands so printing is instantaneous and doesn’t open external apps. • Clean, Flutter-native code (Dart, platform channels or FFI where needed) that I can drop into an existing project. Acceptance check 1. I tap “Discover printers” and see every reachable device over the four connection types. 2. I pair/select one, print a sample, and the receipt comes out correctly formatted on both 58 mm and 80 mm paper. 3. Text is crisp, images centered, barcodes and QR codes scan, PDFs render page-for-page. 4. No external intents or apps are invoked; everything stays inside Flutter. 5. Source compiles for Android and iOS without breaking existing functionality. If you already have reusable code or proven experience with ESC/POS command sets, that’s a plus—I’m ready to integrate right away.