Java Developer

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