Senior Software Engineer - Customer Agent

About the role

Our team is looking for a Senior Full Stack Engineer to help build the future of Customer Agent, Klaviyo's AI-native conversational platform. In this role, you'll play a critical part in shaping how autonomous service, AI-driven support, and agentic commerce experiences evolve at scale across millions of customer interactions. You'll work across the stack to design, build, and scale systems that power intelligent workflows, conversational experiences, tools integrations, retrieval systems, onboarding flows, observability, and multi-channel customer engagement. You'll help develop both foundational platform capabilities and customer-facing experiences that enable brands to launch, customize, and continuously improve their own highly-configurable AI agents. As a Senior Engineer, you'll tackle complex technical and product challenges, develop multiple solution paths, and evaluate business and architectural trade-offs to determine the best approach. You'll also act as a technical leader and mentor, driving engineering quality, execution, and decision-making across projects. Additionally, you'll be responsible for deploying well-designed, thoroughly tested solutions that prioritize reliability, scalability, and customer impact. The Customer Agent team is building one of Klaviyo's most ambitious and strategic product areas: an extensible AI platform that enables brands to deliver personalized, autonomous customer experiences across channels like chat, email, SMS, and beyond. We operate with high ownership, rapid iteration cycles, and a strong bias toward execution. Every engineer is expected to think holistically about customer outcomes, collaborate deeply across engineering, product, design, data science, and go-to-market teams, and push beyond traditional role boundaries to help the team move faster. Success in this role means shipping high-quality systems quickly, contributing to foundational platform decisions, improving the intelligence and reliability of our agent experiences, and helping define how AI-powered customer engagement evolves at Klaviyo.