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. As a Senior Software Engineer on the Cortex Management Team, you will design, develop, and maintain backend software solutions supporting Five9’s AI initiatives. This role focuses on building scalable, reliable, and high performance backend systems that power end to end platform capabilities. You will be responsible for backend architecture, service design, implementation, testing, and documentation. Working closely with product owners and key stakeholders, you will translate

requirements

into robust backend services and APIs. The role also involves deep technical exploration of emerging technologies and partnering with product teams to bring innovative ideas into production. In addition, this position plays a key role in mentoring other engineers and driving backend engineering best practices across Five9. How You Contribute • Leverage strong expertise in programming languages, frameworks, and development methodologies to solve complex backend and distributed systems challenges. • Write high quality, efficient, and maintainable backend code by following best practices and contributing to core services, APIs, and platform capabilities. • Troubleshoot and resolve complex production and architectural issues by identifying root causes and implementing scalable solutions. • Ensure development stays on track, deliverables meet milestones, and solutions align with business and platform objectives. • Collaborate closely with cross functional teams including product managers, other backend development teams, frontend engineers, and quality assurance to ensure alignment on requirements, functionality, and delivery. • Follow and contribute to engineering processes, service documentation, technical specifications, and API contracts. • Ensure that the development stays on track, milestones are met, and the project aligns with business objectives. Required Skills and Qualifications • 5+ years of industry experience in Java backend development. • Strong proficiency with server side technologies, including: o REST API design and implementation o Microservice architectures o Backend frameworks such as Spring Boot o Databases (SQL, NoSQL, Redis) • Hands on experience designing and implementing scalable, high performance microservices that expose REST APIs. • Experience solving complex problems that span multiple services, products, or distributed systems. • Solid understanding of security best practices and the ability to implement measures to protect applications and data. • Ability to work both independently and as part of a collaborative engineering team. • Strong commitment to delivering high quality, performant, and scalable backend solutions on time and within scope. • Proven ability to mentor other developers through direct guidance and code reviews. • Bachelor’s degree (or equivalent) in a relevant discipline. Desirable Qualifications • Experience with Google Cloud Platform (GCP), Kubernetes, Build tools (Gradle preferred) and CI/CD pipelines (Gitlab preferred) • Experience with Event Driven messaging systems • Experience with Contact Centre technologies, including IVR, Virtual Agents, VoIP, and telecommunications service providers. • Experience with AI Development Tools (Claude preferred) Key stakeholders • Service owners and their teams • Technical leadership and senior management • Engineering 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](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.