I will develop mobile apps with API, firebase, payment, barcode and qr code integration

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dowwell_dev
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dowwell_dev
Stefan Wagner
develop mobile apps with API, firebase, payment, barcode and qr code integration
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develop mobile apps with API, firebase, payment, barcode and qr code integration

About this gig

Need a reliable mobile developer to build or expand your Android or iOS mobile app?


I will develop a functional, scalable mobile app qevelopment tailored to your business, startup, eCommerce or service needs.


What I Can Build:

  • Android & iOS mobile apps
  • Flutter / React Native apps
  • API & backend integration
  • Firebase authentication & database
  • Login, signup & user profiles
  • Payment & subscription integration
  • Barcode & QR code scanning
  • Product & inventory features
  • Push notifications
  • Google Maps & location features
  • Admin dashboard integration
  • Bug testing and app optimization


Tools & Technologies

  • Flutter
  • React Native
  • Dart
  • JavaScript
  • Firebase
  • REST API
  • Node.js
  • Android Studio
  • Xcode


You get clean development, responsive UI, functional integrations and testing before delivery.


Have an existing app or a new app idea? Send me your requirements and let's build it.

  • App type

    • Hybrid

  • Programming language

    • Dart
    • Java
    • JavaScript
    • Kotlin
    • Objective-C
    • PHP
    • Swift
    • TypeScript
    • React Native
    • Flutter

  • Frameworks

    • Flutter
    • Ionic
    • Laravel
    • Angular
    • SwiftUI
    • Node.js
    • React Native

  • Purpose

    • Chat
    • Dating
    • Delivery
    • Streaming
    • Restaurant
    • Medical
    • Health & fitness
    • Travel
    • Ecommerce
    • Real estate

  • Tools

    • Flutterflow
    • Android Studio
    • Unity
    • Xcode
    • Visual Studio Code
    • Visual Studio
    • Supabase

  • Expertise

    • Cross browser/Device compatibility
    • Localization
    • Performance
    • Design
    • Firebase
    • API integration

Get to know Stefan Wagner

Stefan Wagner

Mobile App Developer Bug Fixing API Firebase Barcode QR Scanner

  • FromGermany
  • Member sinceMar 2026
  • Avg. response time7 hours

  • Languages

    English, German, Dutch, French, Hebrew
I'm a Mobile App Developer helping businesses build, fix, and improve Android and iOS apps. I specialize in mobile app development, bug fixing, crashes, API and Firebase integration, payment issues, app performance, and adding barcode, QR code, product scanning, and inventory scanner features. I also help with app updates, deployment, and post-launch maintenance. My focus is clean development, reliable solutions, clear communication, and helping businesses keep their apps working smoothly.

My Portfolio

Other Mobile App Development Services I Offer

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