Full-Stack PBX / VoIP Developer (Cloud PBX Platform)

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., 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.

• 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.

• 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

• Work from home

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.