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

Yottavox; Remote; GBP 80,000 - 100,000; Full time

Job summary

A modern telephony platform developer based in the UK is seeking a Full-Stack PBX / VoIP Developer. The role involves building core PBX functionality and APIs while ensuring telecom-grade reliability. Candidates should have strong VoIP engineering experience and be proficient in backend development and modern front-end technologies. This is a remote position offering competitive compensation and a unique opportunity to build a new platform with no legacy constraints.

Benefits

Competitive salary based on experience

Remote working

Early technical influence

Opportunity for senior/lead role

Qualifications

• Strong VoIP engineering background and experience building PBX or SIP-based systems.
• Deep knowledge of SIP, RTP, media handling, and related telecom protocols.
• Experience with Asterisk and ideally FreeSWITCH.
• Solid backend development skills in Node.js, Go, Python, or C++.
• Experience with React, Vue, or similar front-end technologies.

Responsibilities

• Develop the core PBX functionality, APIs, and admin interface.
• Build call routing, extension logic, IVR, queues, and voicemail.
• Design and implement scalable backend services and REST APIs.
• Develop a modern admin interface using React / Vue.
• Integrate with SIP trunk providers.

Skills

VoIP engineering background

Building PBX or SIP-based systems

SIP, RTP, media handling

Backend development in Node.js, Go, Python, or C++

REST APIs and database design

React, Vue, or similar front-end technologies

Understanding of VoIP security

Tools

Docker

Asterisk

FreeSWITCH

Job description

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
• Work from home

Work Location: Remote