Telephony Engineer

You will build and operate core pieces of GreyLabs AI's Telephony platform - the SIP/WebRTC, PSTN/VoIP, and media-handling layer that every voice call in the product passes through. You'll take features, integrations, and reliability improvements from design through production, working closely with senior engineers who set the platform's architecture. This is a strong role for someone who wants deep, hands-on exposure to real-time communications infrastructure at production scale, with a clear path to owning larger scope as the platform and team grow.

The candidate will have responsibilities across the following functions:

Technical Contribution:

• Build and maintain components of the Telephony service - call initiation and termination, session management, SIP/WebRTC handling, PSTN/VoIP integration, and media processing
• Implement and test integration points between the Telephony platform and the Voice AI layer, including ASR, TTS, and LLM orchestration interfaces
• Support evaluation and integration work with telephony carriers and CPaaS providers - test call flows, load testing, and cutover validation
• Instrument and monitor call quality metrics (latency, jitter, packet loss, MOS scores), and help build dashboards, alerts, and runbooks
• Contribute to failover, redundancy, and disaster-recovery mechanisms for inbound and outbound calling flows, and participate in on-call rotations

Platform Development:

• Build and document APIs and internal tooling that let other engineering teams use the Telephony platform without needing deep infrastructure knowledge
• Write and maintain clear documentation - API references, integration guides, runbooks - as you build features
• Help track and report progress against platform SLAs for availability, latency, and call success rates

Delivery and Execution:

• Own well-scoped features and bug fixes end-to-end, from design through production, communicating progress and blockers proactively
• Investigate and resolve production issues in the telephony stack, documenting root causes and escalating where needed
• Participate in planning and estimation for the Telephony roadmap

Cross-functional Collaboration:

• Work closely with Voice AI engineers to understand integration needs and unblock their use of the platform
• Partner with Infrastructure and DevOps on deployment, scaling, and cost-efficient operation of telephony services
• Follow established practices for call recording consent, data residency, and PII handling in call audio and metadata, and flag gaps as you encounter them
• Work with Security to implement controls required to meet GreyLabs AI's security standards

Requirements:

• 3-5 years of experience in Telephony, Real-Time Communications, or VoIP engineering, with hands-on experience building or maintaining a production SIP/WebRTC or PSTN stack.
• Working knowledge of telephony carriers or CPaaS providers (e. g., Plivo, Twilio, Telnyx, Bandwidth, or equivalents) and the trade-offs between them.
• Experience instrumenting or troubleshooting call quality issues - latency, jitter, packet loss, MOS - using logs, traces, or monitoring tools.
• Comfortable debugging real-time voice/media issues in production, and has participated in an on-call rotation for a customer-facing system.
• Proficient in Python, Go, or an equivalent language, with solid engineering fundamentals - testing, code review, incremental delivery.
• Has built or consumed platform APIs, with an eye for clear documentation and developer-friendly design.
• Exposure to regulated or enterprise B2B environments is a plus - call recording consent, data residency, PII handling, or similar compliance-driven constraints.
• Curious and detail-oriented, comfortable asking questions and working with evolving processes in a fast-moving environment.

Skills

Bandwidth, Go, PSTN, Plivo, Python, SIP, Telnyx, Twilio, VoIP, WebRTC