Sr. Software Engineer - API Gateway

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 Senior Software Engineer with deep expertise in API Gateways, API security, cloud-native systems, and Google Cloud Platform (GCP). In this role, you will help shape the next generation of Five9's modern SaaS platform that powers our industry‑leading Contact Center solutions. You'll be instrumental in building highly available microservices with a strong focus on API Gateway architecture, API Developer Portal development, platform reliability, and secure service communication.

Key Responsibilities

• Contribute to the evolution of Five9's modern SaaS platform that enables enterprises to deliver exceptional customer service powered by AI.
• Design, develop, and maintain highly available, scalable microservices, with a core focus on:
• API Gateway architecture (APIGEE)
• API Developer Portal design and enhancements
• Implement and manage API Gateway policies, authentication flows, routing, throttling, and access controls.
• Ensure APIs are secure, well‑documented, and easily consumable by internal and external developers.
• Monitor API performance, analyze traffic patterns, and identify bottlenecks to optimize system efficiency.
• Drive improvements by staying current with industry best practices in API management, security models, and cloud platform modernization.
• Develop deep understanding of existing systems and contribute meaningfully to architectural decisions.
• Troubleshoot critical issues across the software stack and provide production support as part of the 24/7 on‑call rotation.
• Collaborate cross-functionally with platform engineering, product teams, and architects to deliver robust cloud capabilities.
• Apply strong problem‑solving abilities and broad technology expertise to resolve complex platform challenges.

Required Skills & Experience

• 7+ years of hands-on software development experience.
• Strong expertise in:
• API Gateway technologies (APIGEE required)
• API development using Java, Spring / Spring Boot
• Microservices architecture
• Proven experience building and maintaining API Developer Portals.
• Strong understanding of API security frameworks, policies, and standards.
• Experience with OAuth2, authentication/authorization standards, and identity systems.
• Practical knowledge of GCP or another major cloud provider (GCP strongly preferred).
• Strong debugging skills with ability to dive deep into complex system interactions.
• Experience supporting production systems, monitoring, and participating in on‑call rotations.
• Excellent communication skills and ability to work effectively in a collaborative, high‑performance engineering culture.

Nice to Have

• Hands‑on experience with:

• Service mesh

• Kubernetes

• CI/CD pipeline orchestration

• API analytics & observability tools

• Contribution to open-source tools or cloud-native platform components.

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.