Flutter Mobile Developer

Project overview

For our client, we are looking for an experienced Flutter Mobile Developer to develop a security-critical push-to-talk application with a connection to a TETRA Connectivity Server. The focus is on implementing real-time communication and VoIP functionalities, processing SDS messages, integrating digital radio environments, and developing native Android and iOS components. A specialist with in-depth experience in Flutter/Dart, mobile app architecture, audio and device integration, and connecting modern backend systems and communication interfaces is sought.

Responsibilities

• Development and further development of a security-critical push-to-talk mobile app
• Implementation of real-time communication and group communication functions
• Integration and connection of a TETRA Connectivity Server (TCS)
• Implementation of VoIP functionalities and real-time audio transmission
• Processing and integration of SDS messages (Short Data Service)
• Development of native Android and iOS components
• Integration of backend systems and APIs
• Implementation of authentication mechanisms using OAuth2/OpenID Connect
• Integration of push notifications
• Implementation of audio routing and audio management
• Connection of Bluetooth headsets and PTT buttons
• Ensuring background operation on Android and iOS
• Performing testing, quality assurance, and error analysis
• Setting up and maintaining CI/CD processes
• Implementation of logging and monitoring solutions

Requirements

-Project Data-

• Several years of experience in mobile app development with Flutter and Dart
• Very good knowledge in development for Android and iOS
• Experience with mobile UI/UX design
• Knowledge of modern app architectures such as Clean Architecture and MVVM
• In-depth experience in Voice-over-IP (VoIP)
• Knowledge of SIP, RTP, and RTCP
• Experience with real-time audio transmission
• Know-how in push-to-talk (PTT) and group communication
• Knowledge of TETRA or digital radio environments
• Experience with group calls and individual calls
• Knowledge in the area of SDS (Short Data Service)
• Understanding of priority and emergency call communication
• Experience in integrating TETRA Connectivity Servers (TCS)
• Good knowledge of REST APIs and MQTT
• Experience with OAuth2 and OpenID Connect
• Knowledge in backend integration
• Experience with audio management and audio routing on mobile platforms
• Knowledge in integrating Bluetooth headsets and hardware buttons
• Experience with Android SDK
• Very good knowledge of iOS technologies such as CallKit, PushKit, and AVAudioSession
• Experience with App Store and Play Store deployments
• Confident use of Git and version control
• Experience in testing and quality assurance
• Knowledge of CI/CD pipelines
• Experience with logging, monitoring, and error analysis

Project details

Munich

Start Date: 01.01.2027

End Date: approx. 6 months

Utilization: Full-time

• Start: 2027-01
• Duration: 6 Monate
• Remote: hybrid
• Location: München, Deutschland, DE
• Languages: German