Java Developer

Adecco; Ipswich; Hybrid; GBP 40,000 - 60,000; Part time

Job summary

Ipswich-based Java Developer role focusing on SIP/VoIP, voice platforms, and AI-driven voice services. Hybrid work arrangement in a telecoms environment, delivering large-scale voice and cloud-enabled solutions.

The contract is 6 months, Inside IR35, with responsibilities spanning development, deployment, and troubleshooting of voice applications across AWS/Azure/GCP. Strong emphasis on SIP, JAIN SLEE or SIP Servlet, and telecoms security considerations.

Qualifications

• 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.

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.

Skills

Java development

SIP/VoIP

RTP/RTCP

SIP Servlet

JAIN SLEE

FreeSWITCH

Asterisk

Cloud AWS

Azure/GCP

Troubleshooting

Tools

Docker

Kubernetes

WebRTC

TLS/SRTP

Metaswitch Rhino SLEE

Oracle OCCAS

Job description

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