Senior Staff Engineer | AI Voice Engineering

Join us in bringing joy to customer experience. Five9 is a leading provider of cloud contact center software, bringing the power of cloud innovation to customers worldwide.

Living our values everyday results in our team-first culture and enables us to innovate, grow, and thrive while enjoying the journey together. We celebrate diversity and foster an inclusive environment, empowering our employees to be their authentic selves.

About the Role

We are looking for a Senior Staff Engineer, AI Voice Engineering, who will be responsible for the software architecture and software development of Five9's AI Agent voice orchestration software platform. This platform handles real-time streaming voice, including RTP/SIP, integration with speech recognition engines, speech synthesis engines, end of turn model execution and interruption model inference.

As a senior individual contributor, you'll not only be one of the most senior developers on the team, you'll also mentor junior engineers and set technology direction for platform. You'll work with other teams, collaborating cross-functionally to make sure complete solutions are delivered. You'll make some of the most important technology decisions and be in the driver's seat for the platform evolution. You'll also get your hands dirty working direcdtly on the software, diagnosing issues, and helping uplevel the team to reach the highest levels of performance. Your responsibility extends through deployment and operations (we practice devops), and you will ensure the software platform is low latency, scalable, reliable, observable and maintainable by Five9.

What You'll Do

• Lead architecture and development of real-time AI voice systems
• Design and optimize low-latency voice pipelines using RTP/SIP
• Integrate ASR, TTS, and AI inference services
• Mentor engineers and lead technical best practices
• Collaborate with Product, AI, Infrastructure, and SRE teams
• Own the full lifecycle: design, development, deployment, and operations
• Ensure scalability, reliability, and observability

Required Qualifications

• 10+ years of overall software development experience
• 5+ years building real-time voice systems in C++
• 1+ year experience with real-time GenAI voice platforms
• Bachelor's or higher degree in Computer Science or related field

Technical Skills

Modern C++ (C++17+), RTP/SIP, audio codecs, SIP/SDP, ASR/TTS integration, AI APIs, cloud platforms (AWS/Azure/GCP), CI/CD, containers, SRE principles

Leadership & Impact

Lead architecture for mission-critical systems

Mentor engineers and influence platform-wide decisions

Balance latency, quality, cost, and reliability trade-offs

Five9 embraces diversity and is committed to building a team that represents a variety of backgrounds, perspectives, and skills.  The more inclusive we are, the better we are.  Five9 is an equal opportunity employer.

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Note: Five9 will never request that an applicant send money as a prerequisite for commencing employment with Five9.