To be successful in this role you have: Hands-on experience building VoIP systems using SIP/RTP protocols; Practical knowledge of Kamailio, RTPEngine, FreeSWITCH, SBCs, and PSTN systems (or similar); Working knowledge of PSTN infrastructure and telecom protocols; Experience integrating applications on top of LLMs (using existing models, not building them); Experience in prompt engineering and developing LLM based features. As a Staff Machine Learning Engineer - VoIP Infrastructure you will: Contribute to the design, development and implementation of VoIP infrastructure, telephony platforms, and observability features that power AI-driven voice workloads.