Salary: £50,000 - 65,000 per year Requirements: SIP / VoIP and related protocols (SDP, RTP, RFC2833 / RFC4733, etc.) Python or another object-oriented language (5 years) Object-oriented design principles HTTP / RESTful APIs Flask or Django, including Jinja, Pytest, SQLAlchemy, and Marshmallow Secure systems design and development (software and network level) SIP/RTP troubleshooting using tools such as Wireshark Git / GitHub (or similar version control systems) Docker containerisation Linux (Ubuntu-based) environments Full driving licence with car due to the clients location Responsibilities: Designing, developing, and enhancing an existing enterprise SIP platform and supporting services Building new value-added services and capabilities around the core platform Developing integrations with third-party systems, including AI-based voice recognition, transcription, and sentiment analysis services Ensuring secure software design and development at both application and network levels Analysing, troubleshooting, and resolving SIP/RTP and platform-level issues Contributing to secure development processes, policies, and compliance with standards such as ISO 27001 and PCI-DSS Collaborating closely with other developers and stakeholders to deliver high-quality, scalable solutions Technologies: AI Django Docker Flask Git GitHub HTTP Linux Network Python REST Ubuntu pytest ArgoCD CI/CD Support Kubernetes MongoDB MySQL OAuth More: We are an established UK technology company, expanding our Software Development Team. We are looking for an experienced Senior Software Developer to help evolve a large-scale, enterprise-grade SIP platform and its associated REST APIs. This is an excellent opportunity to work on complex, real-world systems in a collaborative, technically strong environment. We offer a supportive, innovation-led workplace where your ideas and expertise will have a real impact. Our benefits include 24 days’ annual leave plus bank holidays, pension, life insurance, private medical insurance, and opportunities for professional development. last updated 5 week of 2026