Location: Remote Employment Type: Full-time Position Experience Level: Senior (5+) About Us Next generation of noninvasive cardiac diagnostics RPM SaaS platforms for heart health, using AI, digital twins and wearables. Position Overview We are seeking a senior VoIP and SIP systems engineer with advanced expertise in OpenSIPS or Kamailio SBC infrastructure. This role requires hands-on experience designing, implementing, and optimizing high-performance SIP environments. The candidate must have a deep knowledge of SIP signaling, media handling, and complex routing, combined with strong programming skills to develop or customize SBC modules. Key Responsibilities Design, deploy, and maintain SBC solutions using OpenSIPS or Kamailio for large-scale, latency-sensitive environments. Design and implement complex call routing logic across SIP stacks, including interworking with FreeSWITCH and Asterisk. Develop and modify OpenSIPS or Kamailio modules in C, with the ability to manipulate SIP headers and handle advanced protocol logic. Build and maintain real-time voice and modem-over-IP services optimized for low latency and high reliability. Configure and secure Linux-based systems, including IP tables, firewall rules, NAT, and network isolation. Deploy and manage containerized environments using LXC and LXD. Troubleshoot advanced SIP, RTP, NAT traversal, and interconnection issues across multi-vendor environments. Collaborate on architecture decisions involving scaling, HA, and multi-data-center SIP deployments. Required Skills & Experience Expert-level proficiency with OpenSIPS or Kamailio SBC platforms. Advanced understanding of SIP signaling, media handling, NAT traversal, and protocol interoperability. Strong experience with FreeSWITCH and Asterisk from both SIP and routing perspectives. Proficiency in C for SIP module development; ability to modify source code to meet specific requirements. Proficiency in Golang. Expert Linux administration skills, including performance tuning, networking, and security. Hands-on experience with LXC/LXD containerization. Proven ability to deliver carrier-grade, high-availability VoIP services. Strong problem-solving skills for diagnosing and resolving complex SIP and network issues. Desirable Skills Experience with lawful intercept, B2BUA media engines, or real-time streaming integration is a plus.