Java Developer (SIP/VoIP)

Ipswich (Hybrid) | 6 Month Contract | Inside IR35

My client, a leading telecoms company, is looking for an experienced Java Developer to join a team delivering next-generation voice and communications platforms. This is an exciting opportunity to work on large-scale telecoms services, cloud technologies and AI-powered voice solutions.

What You'll Be Doing

• Developing and enhancing SIP-based voice applications using Java


• Working with JAIN SLEE and SIP Servlet frameworks


• Supporting and integrating voice platforms including FreeSWITCH and Asterisk


• Deploying and supporting solutions across AWS, Azure and GCP


• Integrating Speech-to-Text, Text-to-Speech and AI-driven voice services


• Troubleshooting voice quality, call routing and network performance issues

Essential Skills

• Strong commercial Java development experience


• Experience with SIP, VoIP, RTP/RTCP and SDP


• Knowledge of JAIN SLEE and/or SIP Servlet frameworks


• Experience with FreeSWITCH or Asterisk


• Cloud experience across AWS, Azure or GCP


• Strong troubleshooting skills within telecoms or voice environments

Nice to Have

• Docker and Kubernetes


• WebRTC


• Telecoms security protocols including TLS and SRTP


• Metaswitch Rhino SLEE or Oracle OCCAS experience

If the role aligns with your expeirence, pelase apply with your updated CV