Software Engineer / Developer - Voice Services

Salary: £76,000 - 97,000 per year

Requirements:

• Professional experience with Java, including multi-threading and network programming.
• In-depth knowledge of Java.
• Experience using JAIN SLEE and SIP Servlet frameworks for Java applications.
• Hands-on experience configuring and scripting with FreeSWITCH or Asterisk.
• Solid understanding of SIP, RTP/RTCP, and SDP.
• Experience integrating cloud speech APIs such as AWS Transcribe/Polly, Azure Speech, and Google Cloud Speech-to-Text.
• Experience deploying and managing applications on AWS, Azure, and GCP.
• Proficiency with Wireshark or sngrep for VoIP troubleshooting.
• Experience with Java telephony frameworks such as Metaswitch Rhino SLEE or Oracle OCCAS.
• Understanding of containerisation using Docker and Kubernetes in cloud environments.
• Knowledge of WebRTC and telephony security standards like TLS and SRTP.

Responsibilities:

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

Technologies:

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

More:

Flint are seeking a Software Engineer/Developer to build, maintain, and optimize our clients next-generation communication platforms. We bridge the gap between traditional telecommunication protocols and modern cloud-based AI, with a core focus on stable SIP services, open-source media engines, and advanced Speech AI technologies across multi-cloud environments.

last updated 37 week of 2026