VoIP Operations & Production Release Engineer

Salary: £50,000 - 75,000 per year

Requirements

• We require 5+ years in a senior operations, SRE, or release management role on a real-time voice/VoIP platform at scale.
• We require strong hands-on expertise with Kamailio and FreeSWITCH, or similar platforms, in production.
• We require deep, practical knowledge of SIP, SDP, RTP/SRTP, codecs, and common interoperability issues.
• We require demonstrable experience operating SBCs in production with any major vendor.
• We require strong experience with SIP tracing tools such as HOMER, sngrep, and Wireshark.
• We require proven AWS production experience, including infrastructure as code with Terraform or CloudFormation.
• We require solid Linux administration, networking knowledge, and shell scripting skills.
• We require database administration experience with MySQL/MariaDB or PostgreSQL, including replication and tuning.
• We require experience leading change management and production releases in a regulated or carrier-grade environment.
• We require strong written communication skills for runbooks, RCAs, change records, and customer-facing incident notes.
• We prefer experience with WebRTC, Janus, or Jitsi.
• We prefer exposure to STIR/SHAKEN, KYC, and number-validation regimes.
• We prefer container and orchestration experience with Docker, Kubernetes, or EKS for stateless components.
• We prefer experience with HOMER or Heplify deployments at scale.
• We prefer carrier-grade interconnect experience, including SIP-I, SIP-T, or SS7/Sigtran awareness.
• We prefer programming experience in Python, Go, or Lua for automation and Kamailio scripting.
• We prefer experience operating UCaaS, CCaaS, or CPaaS platforms.
• We prefer relevant certifications in AWS, Linux, or security.
• We require experience as a VoIP Engineer, ideally 4 years or more.
• We require authorization to work in the United Kingdom.

Responsibilities

• We own the end-to-end production release lifecycle, including change intake, risk assessment, scheduling, CAB approval, execution, validation, and rollback.
• We maintain the release calendar across staging and production environments and coordinate maintenance windows with carriers, customers, and internal stakeholders.
• We define and enforce release governance through change tickets, deployment runbooks, pre- and post-checks, and back-out plans for every change.
• We drive continuous improvement of CI/CD pipelines for SIP application code, dial-plan logic, and infrastructure as code.
• We conduct post-release reviews and feed lessons learned back into engineering.
• We operate, tune, and troubleshoot Kamailio as the SIP edge, registrar, and proxy layer.
• We operate FreeSWITCH as the media, B2BUA, IVR, and conferencing layer.
• We manage Session Border Controllers and handle signalling and media policy, topology hiding, codec interworking, registration throttling, and DoS protection.
• We tune call-handling capacity, monitor voice quality metrics, and resolve issues such as one-way audio, ghost calls, registration storms, and SIP loops.
• We perform live and forensic SIP tracing using HOMER, sngrep, Wireshark, ngrep, tcpdump, and pcap analysis.
• We diagnose interoperability issues across SIP variants and complex dialog flows.
• We build dashboards and alerting for call quality, ASR, ACD, NER, and SIP response-code distributions.
• We manage SIP trunks and interconnects with upstream carriers and tier-1 wholesalers.
• We own carrier onboarding, IP whitelisting, codec and profile alignment, and signalling testing.
• We coordinate with carriers on incident triage, MOS degradation, false answer supervision, and trunk failover.
• We maintain and evolve least cost routing logic, prefix tables, and routing policies across multiple carriers.
• We handle DID and number provisioning, porting workflows, E.164 normalisation, CLI and P-Asserted-Identity handling, and STIR/SHAKEN where applicable.
• We manage number inventory, regulatory tagging, and emergency services routing where in scope.
• We operate the production estate on AWS, including core networking, storage, compute, identity, and monitoring services.
• We maintain infrastructure as code and configuration management.
• We capacity plan for real-time workloads and media performance requirements.
• We administer databases supporting routing, media, call detail records, and provisioning systems.
• We manage replication, backups, schema migrations, and tuning for high-write workloads.
• We operate Redis and time-series stores for session state, rate limiting, and metrics where applicable.
• We harden SIP edges against fraud and abuse, including toll-fraud prevention, brute-force protection, geo-fencing, anti-flood controls, ACLs, and rate limiting.
• We manage firewalls at the network and host level.
• We operate TLS for SIP signalling and SRTP for media, including certificate lifecycle and cipher policy management.
• We support security audits, vulnerability management, patch cycles, and incident response.
• We maintain alignment with relevant security and compliance frameworks where applicable.
• We maintain monitoring and alerting across the stack.
• We lead incident response, including bridge calls, root cause analysis, postmortems, and permanent fixes.
• We define and report on service objectives and voice quality metrics.

Technologies

• AWS
• CI/CD
• Cloud
• Docker
• Support
• Jitsi
• Kubernetes
• Linux
• MariaDB
• MySQL
• Network
• PostgreSQL
• Python
• Redis
• Security
• Terraform
• Windows
• Ansible
• CloudWatch
• Debian
• DevOps
• EC2
• GitHub
• GitLab
• Grafana
• IAM
• Jenkins
• MPLS
• NAT
• Oracle
• Prometheus
• RHEL
• TCP/IP
• Ubuntu
• XML
• Zabbix

More

We are hiring an experienced Operations & Production Release Engineer to own the stability, security, and evolution of our VoIP and telecommunications platform. This is a hands-on hybrid or remote role based in London, where you will work across Engineering, Development, Support, and Security to protect real-time voice services built on open-source SIP stacks, SBCs, and AWS cloud infrastructure. We offer a competitive salary and bonus, pension, private medical insurance, on-call allowance, training and certifications, and hybrid or remote working arrangements.

last updated 21 week of 2026