Full-Stack PBX / VoIP Developer (Cloud PBX Platform)
17 hours ago
Birmingham
About Us We are building Yottavox® - a modern cloud-hosted PBX platform designed for clarity, performance, and scalability. The product is currently in development and we are now hiring a talented Full-Stack PBX/VoIP Developer to join at an early stage and take a key role in the build. This is a unique opportunity to work on a new platform from the ground up, without legacy constraints, and help shape a clean, modern telephony system built for real-world operators and end-users. The Role You will be responsible for developing the core PBX functionality, APIs, and admin interface. Working closely with design and product, you’ll build a reliable, secure, multi-tenant VoIP platform with a strong focus on quality and long-term maintainability. Key Responsibilities 1. Core PBX & VoIP Development • Build call routing, extension logic, IVR, queues, voicemail, and CDR workflows., • Develop predictable, efficient, secure VoIP behaviour with multi-tenant capability. 2. Backend Architecture & APIs • Design and implement scalable backend services and REST APIs for provisioning, configuration, and reporting., • Follow clean architectural patterns and maintain high coding standards. 3. Frontend Implementation • Develop a modern admin interface using React/Vue (or similar)., • Work from wireframes and collaborate with design to deliver a clean, intuitive experience. 4. Integrations & Infrastructure • Integrate with SIP trunk providers, manage number routing and failover logic., • Build tooling for diagnostics, monitoring, real-time events, and system health. 5. Quality, Security & Stability • Ensure telecom-grade reliability with proper SIP/RTP handling, NAT traversal, SRTP/TLS, fraud controls, and error management., • Optimise for low latency, resilience, and predictable performance under load. 6. Documentation & Technical Clarity • Maintain clear documentation for APIs, data models, call flows, and system components., • Ensure all work is structured, readable, and easy to maintain or extend. 7. Collaboration & Delivery • Work closely with design, product, and a fractional architect., • Communicate clearly, follow consistent patterns, and deliver high-quality implementations without micro-management. 8. Environment Setup & Testing • Support containerised dev environments, basic CI/CD, and automated tests for critical flows., • Prepare for staging and early-access deployment. Required Experience: • Strong VoIP engineering background and experience building PBX or SIP-based systems., • Deep knowledge of SIP, RTP, media handling, and related telecom protocols., • Hands-on experience with Asterisk and ideally FreeSWITCH.., • Solid backend development skills in Node.js, Go, Python, or C++., • Strong understanding of REST APIs, authentication, and database design., • Experience with React, Vue, or similar front-end technologies., • Familiar with Docker, cloud hosting environments, and modern DevOps practices., • Good understanding of VoIP security (TLS/SRTP, NAT traversal, rate limiting). Nice to Have: • Experience with multi-tenant SaaS architecture., • Knowledge of SIP trunking, number routing, failover logic., • Familiarity with call recording, CDRs, and telecom observability tools., • Experience integrating with SBCs or media servers. What We Offer: • Competitive salary based on experience., • Remote working, • A chance to build a new platform from scratch - no legacy code., • Early technical influence with significant autonomy., • Opportunity to grow into a senior or lead role as the platform scales. Job Type: Fixed term contract Contract length: 12 months (with strong potential for permanent on review) Benefits: • Casual dress