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
Five9 is seeking a Staff Software Engineer – Call Control to lead the architecture, design, and development of our real‑time Call Control platform. This platform powers mission‑critical voice capabilities, including low‑latency call control, high‑quality voice streaming, integration with AMD (Answer Machine Detection) vendors, and global voice expansion using Kafka and Kafka Connect for a scalable, distributed architecture.
This core platform is essential to ensuring accuracy, scalability, reliability, and 99.999% availability, enabling efficient use of contact center resources and delivering an outstanding customer experience.
As a senior individual contributor, you will be one of the most experienced engineers on the team. You will mentor engineers, guide architectural direction, collaborate with cross‑functional teams, and drive platform evolution. This role is hands‑on, involving system design, development, debugging, and production operations following DevOps practices. You will ensure the platform remains low‑latency, observable, scalable, reliable, and easy to maintain.
What You’ll Do
• Lead architecture and end‑to‑end development of real‑time voice systems.
• Design and optimize low‑latency, high‑performance microservices using Java/Spring Boot and Java/Kotlin.
• Apply strong object‑oriented design, design patterns, clean code practices, refactoring, and code-quality standards.
• Build distributed, event‑driven systems with high scalability, reliability, and low latency.
• Design and evolve REST APIs, ensuring backward compatibility and strong service contracts.
• Use Redis for caching, distributed locking, application state management, and fast data access.
• Build observability into systems—tracing, structured logging, metrics, and profiling.
• Work with public cloud platforms (AWS and GCP; GCP preferred).
• Mentor engineers, drive technical best practices, and elevate code and design quality.
• Collaborate closely with Product, AI, Infrastructure, and SRE teams to deliver complete solutions.
• Own the full software lifecycle: design, implementation, deployment, and production operations.
• Ensure the platform meets Five9’s standards for scalability, reliability, performance, and observability.
Required Qualifications
• 10+ years of professional software development experience.
• 5+ years building real‑time voice systems using Java/Kotlin and C++.
• 1+ year hands‑on experience with real‑time GenAI voice platforms.
• Bachelor’s degree or higher in Computer Science or a related field.
Required Technical Skills
• Languages/Frameworks: Java, JS, Kotlin
• Voice & Real-Time Comms: SIP, RTP, RTCP
• Cloud Platforms: GCP / AWS
• Databases: MySQL, PostgreSQL
• DevOps: CI/CD, Containers, SRE principles
• AI Integrations: AI APIs
Good to Have
• Node.js, TypeScript, WebRTC experience
Leadership & Impact
• Lead architecture for mission‑critical, high‑availability systems
• Mentor and guide engineering teams
• Drive platform-wide technical decisions
• Balance trade‑offs across latency, quality, cost, and reliability
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.
View our privacy policy, including our privacy notice to California residents here: https://www.five9.com/pt-pt/legal.
Note: Five9 will never request that an applicant send money as a prerequisite for commencing employment with Five9.
