1. JOB DESCRIPTION
You will participate in developing core mobile components for a multi-channel customer care platform (VCX):
Develop Mobile SDK (Android/iOS) for:
Voice Call (VoIP, SIP, WebRTC)
Video Call (1-1, group, real-time)
Build plug-and-play SDKs that enable enterprise customers to easily integrate into their systems
Optimize call quality:
Reduce latency
Improve audio/video quality
Handle poor network conditions and connection loss
Develop call features:
Mute, hold, transfer, record
Push notifications for incoming calls
Handle background call processing
Integrate with backend systems:
SIP Server / Media Server
Signaling server (WebSocket, REST API)
Participate in SDK architecture design:
Modular, scalable, and maintainable
Support cross-platform (if needed)
Write technical documentation:
API documentation
Integration guides for customers
Support partners in SDK integration and troubleshoot real-world issues
2. REQUIREMENTS
Mandatory
2–5+ years of experience in mobile development:
Android (Kotlin/Java) or iOS (Swift/Objective-C)
Experience in at least one of the following areas:
WebRTC / VoIP / SIP / real-time communication
Knowledge of:
Networking (TCP/UDP, HTTP, WebSocket)
Media streaming (audio/video)
Experience with:
Building SDKs / libraries / frameworks
Performance, memory, and battery optimization
Preferred
Experience with:
CallKit (iOS), ConnectionService (Android)
PushKit, Firebase Cloud Messaging
Experience developing:
Call apps, chat apps, video conferencing systems
Understanding of:
SIP protocol, RTP/RTCP
Media servers (Asterisk, FreeSWITCH, Janus, Kurento, etc.)
Experience with:
Flutter / React Native (SDK bridge)
Working with B2B customers
3. OTHER REQUIREMENTS
Product mindset with an understanding of customer needs
Ability to debug complex issues (network, real-time systems)
Proactive with strong ownership of product quality
Ability to read and understand English technical documents
4. BENEFITS
Opportunity to work on a large-scale multi-channel customer care platform at Viettel
Exposure to advanced technology challenges:
Real-time communication
Video calling
Customer Experience (CX) systems
Career development opportunities:
System architecture
SDK platform (B2B products)
Technology environment: AI + Big Data + Customer Experience
Competitive salary + performance-based bonuses












