About the role We are hiring a Senior VoIP Engineer to help shape and evolve a large-scale real-time communications platform, including the migration from legacy infrastructure to a modern architecture. This role sits at the intersection of telecom, networking, and software engineering, and requires practical, production-grade experience across all three. You will contribute directly to architectural decisions, build new services, and improve voice systems that customers rely on every day. This is a developer role — not an integrator or operator position. We are looking for someone who has written code that routes, manipulates, and reasons about SIP traffic at scale. What you'll do Design and develop services for a production-grade real-time communications platform. Build and maintain telephony applications using open-source and commercial platforms. Contribute to and help lead the migration from legacy infrastructure to a modern architecture. Design and implement call routing logic, SIP signaling flows, and media handling. Troubleshoot complex issues in live voice environments — signaling, media, performance, and reliability. Partner closely with operations and cross-functional engineering teams to ensure service stability and scalability. What we're looking for: Required 5+ years as a developer building VoIP / SIP systems — not solely operating or integrating commercial platforms. Hands-on production experience with both layers of an open-source SIP stack: A B2BUA / media server: Asterisk or FreeSWITCH A SIP proxy / routing layer: Kamailio or OpenSIPS Proven track record building and operating voice platforms in production. Solid understanding of SIP signaling, dialog state, NAT traversal, and real-time media behavior. Comfort reading and writing code, not only configuration. Adv