Location: Bristol In House/Hybrid (must be within commutable distance of Bristol)
Employment Type: Full-time
Experience Level: Senior
Salary: £80k - £100k
About the Role
We are seeking an experienced Senior Telephony Engineer to design, build, and scale a robust, cloud-based voice communications platform. This role will focus on developing the core telephony infrastructure that powers programmable voice, call routing, real-time audio processing, and system reliability at scale.
You will play a key role in shaping the architecture of a modern communications platform and will work closely with backend, DevOps, and AI teams to deliver high-quality, production-grade voice services.
What You’ll Do
* Architect and implement a scalable telephony infrastructure supporting inbound and outbound voice calls.
* Design call routing, session management, and failover strategies for high availability.
* Build and maintain real-time voice services using SIP, RTP, and WebRTC technologies.
* Develop APIs and internal tooling for call control, provisioning, and monitoring.
* Ensure low-latency, high-quality audio and reliable call delivery across regions.
* Collaborate with AI teams to integrate voice services with speech recognition, TTS, and conversational agents.
* Lead troubleshooting and optimization of complex telephony and networking issues.
* Define best practices for security, compliance, and observability within voice systems.
What We’re Looking For
* 5+ years experience working with telephony or real-time communications systems.
* Strong knowledge of SIP, RTP, VoIP, and call signaling protocols.
* Experience building or operating large-scale voice or communications platforms.
* Proficiency in at least one backend language (e.g., Python, Go, Java, or C++).
* Strong understanding of networking concepts (NAT traversal, codecs, latency, jitter).
* Experience with cloud infrastructure and distributed systems.
* Ability to lead technical decisions and collaborate across multiple engineering disciplines.
Nice to Have
* Experience with WebRTC media servers or SIP application servers.
* Familiarity with telecom regulations, number provisioning, and compliance requirements.
* Experience with monitoring real-time systems and call-quality metrics.
* Exposure to AI voice pipelines (ASR, TTS, real-time streaming).
Why Join Us
* Opportunity to build a foundational communications platform from the ground up.
* Work on complex, real-time systems at scale.
* Influence architecture and long-term technical direction.
* Flexible working arrangements and competitive compensation.
* Collaborative team environment with a strong engineering focus.