Senior Software Engineer in AI - Java Spring, backend

Five9 is a leading provider of cloud software for the enterprise contact center market, bringing the power of the cloud to thousands of customers and facilitating more than three billion customer interactions annually. Five9 has led the cloud revolution in contact centers, helping organizations transition from legacy premise-based solutions to the cloud. The cloud contact center market has become the hot space for innovation in real-time communications, and is the tip of the spear for the application of Artificial Intelligence. Five9 has led the charge with its Genius AI platform. Five9 offers a high-energy environment with lots of room for personal and professional growth. Our innovative AI team is seeking a talented and experienced Senior Software Engineer to join our Voice of Customer (VOC) team. AI experience is required for this role - you will work hands-on with AI technologies from vendors like Azure, OpenAI, Google, Databricks, IBM, and Amazon, and continue to build on some of the hottest skills on the market. An ideal candidate for us is an experienced engineer who is passionate about building high performance web platforms and applications, a brilliant problem solver and a creative self-starter.

Voice of Customer (VOC) is Five9’s AI-powered customer insights product. Every day, contact centers handle enormous volumes of voice and chat conversations that hold the clearest signal about what customers actually want - and almost none of it gets read. VOC applies AI to those conversations at scale to surface why customers are reaching out, how those reasons cluster and shift over time, and where the business should act. The result is a set of insights and analytics that CX and operations leaders use to make decisions, with the ability to trace any insight back to the conversations behind it.

 Key Responsibilities:

• Be part of an agile team developing a scalable, highly available application platform using modern PaaS platforms such as GCP.
• Utilizing Java Spring Framework and Spring Boot for creation of highly scalable, robust microservices. Reactive programming is desirable but not required.
• Build and scale the backend services and data pipelines that turn large volumes of customer conversations into insights.
• Integrate AI and LLM services into those pipelines, and make sure the insights they produce are accurate and traceable.
• Understand how to leverage PaaS components, such as message buses, cloud functions (lambdas), and noSQL databases when developing software in order to achieve scalability, reliability, and operability.
• Participate and contribute to requirements analysis and feature grooming.
• Document and communicate clearly architecture and implementation solutions.
• Have ownership of your code in production, including on-call, troubleshooting.

 Key Skills:

• 5+ years software development experience (mandatory).
• Highly proficient in Java - Spring Framework, Spring Boot, and REST API design. Reactive programming (rxjava or similar) is desirable but not required.
• Hands-on experience building AI-powered products or services, including practical LLM integration - prompt design, structured output, evaluation, and managing cost and latency.
• Hands-on experience designing and implementing scalable, event-driven microservices.
• Experience with PaaS hosted relational and no-SQL databases (mySQL, BigQuery, DataStore, Redis, etc).
• Experience with public cloud technologies and tools - Kubernetes, noSQL databases, message buses.
• Experience with large-scale data processing and analytics is a plus.
• Familiarity with vibe coding using different AI tools like Claude Code.
• Experience in developing automated test cases with modern tools such as JUnit.
• Experience in operational code ownership - on-call, troubleshooting, uptime.
• Experience in applying design patterns and separating concerns in a distributed system.
• Solid understanding of security best practices for protecting applications and data.
• Must have experience working within an Agile/Scrum team.
• Positive, self-motivated and enthusiastic attitude with a strong sense of ownership.
• Strong pro-active communication skills, both verbal and written.
• AI skills in speech recognition and natural language processing are a plus but not required.
• Experience in contact center software is a plus but not required.