Lead SIP / VoIP Infrastructure Engineer We are looking for a hands-on Lead SIP / VoIP Infrastructure Engineer to own, configure and troubleshoot the telephony layer powering a real-time AI voice platform. This is a high-impact role for someone with deep SIP and VoIP infrastructure experience who can work independently across encrypted SIP, SIP trunking, gateways, Jambonz configuration, Twilio SIP, WebSocket-to-SIP bridging and AWS-based voice deployments. You will play a key role in reducing vendor dependency, strengthening internal technical capability and ensuring the voice infrastructure is secure, reliable, scalable and ready to support high-volume customer deployments. This is not a general DevOps role — this position requires someone who can read PCAPs, understand SIP call flows, debug failed calls and confidently manage the infrastructure behind live AI voice interactions. Key Responsibilities Own SIP configuration, troubleshooting and optimisation across the voice infrastructure. Configure and support SIP trunking, SIP gateways and encrypted SIP/TLS endpoints. Work with Jambonz and related platforms such as Kamailio, FreeSwitch or Asterisk. Configure, test and troubleshoot Twilio SIP trunks. Debug SIP call flows using PCAP analysis and tools such as Wireshark. Build and support WebSocket-to-SIP bridging for real-time AI voice interactions. Manage SSL/TLS certificates for SIP endpoints using ACM, Let’s Encrypt or similar. Deploy and maintain AWS-based VoIP infrastructure across EC2, VPC, Security Groups, ALB, NLB and CloudFormation. Support secure call routing, IP whitelisting, TLS compliance and network-level controls. Partner with engineering, DevOps and product teams to integrate telephony infrastructure with AI voice orchestration systems. Support call recording architecture, including S3 storage and recording cluster scalability. Document configuration patterns, troubleshooting runbooks and deployment standards. Identify risks, reduce vendor dependency and improve overall platform reliability. About You You are a practical, hands-on SIP and VoIP specialist who enjoys solving complex infrastructure problems. You are comfortable working through ambiguity, reading call traces, debugging live systems and making pragmatic decisions quickly. You will be suited to this role if you enjoy owning critical systems, improving reliability and building the technical foundations that allow a modern AI voice platform to scale. Required Experience Strong hands-on experience with SIP protocol, SIP trunking, gateways and call routing. Deep understanding of encrypted SIP, including SIP/TLS and port 5061. Strong PCAP analysis and SIP troubleshooting experience, ideally using Wireshark. Experience with Jambonz, Kamailio, FreeSwitch or Asterisk. Experience setting up and debugging Twilio SIP trunks. Experience with WebSocket-to-SIP bridging, including wss:// to SIP flows. Strong AWS infrastructure experience across EC2, VPC, Security Groups, ALB, NLB and CloudFormation. Experience managing SSL/TLS certificates for SIP endpoints using ACM, Let’s Encrypt or similar. Ability to troubleshoot complex voice, networking and application issues independently. Strong documentation and communication skills. Comfortable working in a fast-moving startup or scaleup environment. Nice to Have Experience with Pulumi or Terraform for telephony infrastructure as code. Experience integrating with voice AI orchestrators such as VAPI or similar. Production experience with Jambonz. Experience designing call recording architecture and storing recordings in S3. Experience scaling recording clusters or real-time voice workloads. Experience with enterprise security controls, including IP whitelisting and TLS 1.2 / TLS 1.3 compliance. Exposure to conversational AI, speech-to-text, text-to-speech or real-time voice agent platforms. Experience in contact centre, telco, unified communications, carrier, CPaaS or cloud telephony environments. Why Join Join a fast-growing team building real-world conversational AI products. Own a critical infrastructure layer behind live AI voice deployments. Help reduce vendor dependency and build internal technical capability. Work across modern AI, cloud and telephony infrastructure. Take on a high-ownership, high-impact role with genuine influence over platform direction. Flexible, remote-first working environment. Competitive salary and strong growth opportunity.