Voice Services Developer: SIP, Java & Multi-Cloud AI

Rubicon Consulting; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

Rubicon Consulting is seeking a Voice Services Developer on a 4+ year contract based in Suffolk. You will build, maintain, and optimize SIP-based voice services, bridging traditional telephony and cloud-based AI.

Focus areas include Java development, SIP/VoIP, and integration of Speech AI across multi-cloud environments. Responsibilities include developing, testing, and scaling SIP services, managing FreeSWITCH/Asterisk engines, and deploying applications across AWS, Azure, and Google Cloud.

Qualifications

• Proficient in Java with multi-threading and network programming.
• Strong knowledge of JAIN SLEE and SIP Servlet Frameworks.
• Hands-on experience with FreeSWITCH or Asterisk telephony engines.
• Solid understanding of SIP, RTP/RTCP, and SDP.
• Experience integrating cloud Speech APIs (e.g., AWS/Azure/Google) for Speech AI.

Responsibilities

• Develop, test, and maintain SIP-based voice services.
• Configure and scale FreeSWITCH or Asterisk engines.
• Integrate Speech-to-Text and Text-to-Speech workflows.
• Deploy and monitor voice apps across AWS, Azure and GCP.
• Troubleshoot audio quality, call drops, and latency issues.
• Collaborate with senior architects and DevOps teams to rollout scalable conversational AI bots.

Skills

Java

SIP/VoIP knowledge

Multi-threading

Network programming

Speech AI concepts

Tools

Wireshark

sngrep

FreeSWITCH

Asterisk

JAIN SLEE

SIP Servlet Frameworks

Docker

Kubernetes

Job description

Rubicon Consulting is seeking a Voice Services Developer on a 4+ year contract based in Suffolk. You will build, maintain, and optimize SIP-based voice services, bridging traditional telephony and cloud-based AI.

Focus areas include Java development, SIP/VoIP, and integration of Speech AI across multi-cloud environments. Responsibilities include developing, testing, and scaling SIP services, managing FreeSWITCH/Asterisk engines, and deploying applications across AWS, Azure, and Google Cloud.