Software Engineering Specialist

Experis; Greater London; Hybrid; GBP 65,000 - 90,000; Part time

Job summary

Experis is seeking a Voice Services Developer to build and optimize next-generation communication platforms. You will bridge traditional telephony with cloud-based AI, focusing on SIP services, media engines, and Speech AI across multi-cloud environments.

You will work with senior architects and DevOps to deliver scalable voice solutions, integrating STT/TTS and NLP into live streams while supporting hybrid cloud deployments.

Qualifications

• Core language: Java with multi-threading and networking experience.
• In-depth knowledge of Java.
• Experience with JAIN SLEE framework and SIP Servlet Frameworks.
• Hands-on with FreeSWITCH or Asterisk telephony engines.
• Strong understanding of SIP, RTP/RTCP, and SDP.
• Experience with cloud speech APIs (AWS Transcribe/Polly, Azure Speech, Google Cloud Speech-to-Text).
• Experience deploying on AWS, Azure, and GCP.
• Proficiency with Wireshark or sngrep for VoIP troubleshooting.

Responsibilities

• Develop, test, and maintain SIP-based voice services using JAIN SLEE and SIP Servlets.
• Configure and scale FreeSWITCH or Asterisk engines.
• Integrate STT, TTS, and NLP into live streams.
• Deploy and monitor across AWS, Azure, and GCP.
• Troubleshoot audio quality, drops, and latency with network tools.
• Collaborate with architects and DevOps to roll out scalable bots.

Skills

Java

Multi-threading

Network programming

SIP

Speech AI

Tools

JAIN SLEE

SIP Servlets

FreeSWITCH

Asterisk

Wireshark

sngrep

Docker

Kubernetes

Metaswitch Rhino SLEE

Oracle OCCAS

Job description

Software Engineering Specialist
6 months
Hybrid
Inside IR35 - umbrella only
We are seeking a Voice Services Developer to build, maintain, and optimize our next-generation communication platforms. You will bridge the gap between traditional telecommunication protocols and modern cloud-based AI. Your core focus will be developing stable SIP services using Java, managing open-source media engines, and integrating advanced Speech AI technologies across multi-cloud environments.

Key Responsibilities

• SIP Development: Develop, test, and maintain mid-to-high performance SIP-based voice services using JAIN SLEE, SIP Servlets.
• Media Server Administration: Configure, manage, and scale FreeSWITCH or Asterisk communication engines.
• Speech AI Integration: Implement Speech-to-Text (STT), Text-to-Speech (TTS), and Natural Language Processing (NLP) workflows into live voice streams.
• Cloud Operations: Deploy and monitor voice applications across AWS, Azure, and Google Cloud Platform (GCP).
• Troubleshooting: Use network analysis tools to diagnose audio quality issues, call drops, and latency problems.
• Team Collaboration: Work alongside senior architects and DevOps teams to roll out scalable conversational AI bots.

Required Skills & Qualifications

• Core Language: Professional experience with Java, including multi-threading and network programming.
• In depth knowledge of Java
• Good knowledge of java applications using JAIN SLEE framework, SIP Servlet Frameworks
• Telephony Engines: Hands-on experience configuring and scripting with FreeSWITCH or Asterisk.
• Voice Protocols: Solid understanding of SIP, RTP/RTCP, and SDP.
• Speech AI: Experience integrating cloud speech APIs (e.g., AWS Transcribe/Polly, Azure Speech, Google Cloud Speech-to-Text).
• Multi-Cloud Exposure: Experience deploying and managing applications on AWS, Azure, and GCP.
• Tools: Proficiency with Wireshark or sngrep for VoIP troubleshooting.

Preferred Qualifications

• Experience with Java telephony frameworks like Metaswitch Rhino SLEE or Oracle OCCAS.
• Understanding of containerisation using Docker and Kubernetes in cloud environments.