Salary: £45,000 - 70,000 per year

Requirements:

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
Docker and Kubernetes
WebRTC
Telecoms security protocols including TLS and SRTP
Metaswitch Rhino SLEE or Oracle OCCAS experience

Responsibilities:

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

Technologies:

AI
AWS
Asterisk
Azure
Cloud
Docker
GCP
Java
Kubernetes
Network
Oracle
Security

More:

We are a leading telecoms company seeking an experienced Java Developer to join our team delivering next-generation voice and communications platforms. This is a 6 month contract role based in Ipswich with a hybrid working arrangement and is inside IR35. You will work on large-scale telecoms services, cloud technologies and AI-powered voice solutions in a dynamic environment.

last updated 37 week of 2026

Java Developer

Job description