Software Engineer II

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 Team

The Voice Client Team is responsible for delivering critical voice call capabilities for our customer call and contact centre solutions. Our focus is on providing high-quality audio and seamless communication experiences. The team develops native applications for macOS and Windows, along with web-based applications using the latest web technologies.

We work closely with our customers to understand their needs, quickly address concerns, and continuously enhance our products—ensuring exceptional customer experience and measurable business impact.

Role Purpose

The role is focused on identifying customer challenges, leveraging the Five9 Voice Platform, and delivering customer value through solution implementation and ongoing support. This position involves close collaboration with cross-functional teams and occasional direct interaction with customers.

Key Responsibilities

• Work as part of an agile team to design and develop a scalable, highly available global voice platform.
• Apply performance and scalability principles in software development.
• Collaborate with Product Managers, Architects, Engineering Leads, and QA Engineers to deliver robust solutions.
• Mentor and guide junior developers to foster a culture of technical excellence.
• Participate in code reviews and contribute to continuous improvement initiatives.

Required Skills and Qualifications

• 5+ years of experience in software development and VOIP system troubleshooting.
• Strong understanding of WebRTC (in browsers) and/or SIP signalling.
• Expertise in JavaScript, with at least 2 years of hands-on experience in either C++ or Java.
• Experience with debugging, audio media analysis, and use of troubleshooting tools.
• Proven experience in solving complex technical problems within distributed systems.
• Familiarity with Agile/Scrum methodologies.
• Strong ownership mindset, proactive attitude, and excellent communication skills.
• Bachelor’s degree (or higher) in Computer Science, Engineering, or a related field.

Preferred / Desirable Skills

• Understanding of VOIP protocols such as SIP, RTP, RTCP, and other network protocols.
• Experience in Telecom or IoT domains.
• Background in Contact Centre, IVR, Virtual Agents, or Telecommunication Service Provider environments.

Additional Information

This position requires on-call availability as part of the support rotation.

Key Stakeholders

• Product Management Team
• Customer Support Team
• Engineering & QA Teams

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.