Sr. Lead AI Engineer

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny. Job Title: Sr. Lead AI Engineer Location: Boston, MA This role is based in our Boston, MA hub (Hybrid-3x week). About the Role At Klaviyo, we believe the future of software isn’t just better productivity tools for humans—it’s systems that can run, optimize, and adapt themselves based on outcome and reward signals. We’ve already built the infrastructure and applications that sit between businesses and consumers—serving 183,000+ customers, billions of consumer profiles, and hundreds of billions of messages and conversion events. Now we’re investing heavily in Marketing AI and Service AI: the shared services and agentic capabilities that power AI‑native experiences across Klaviyo. As a Sr. Lead AI Engineer in the AI Analytics organization, you’ll be the technical leader for a set of high‑impact AI services and agentic systems. You’ll own architecture and execution for complex, distributed backend systems; guide other engineers through design and implementation; and partner closely with product, machine learning, and data science to turn AI ideas into reliable, scalable production capabilities. This is a hands-on tech lead role, not a people‑manager role. How You’ll Make a Difference Define and improve the engineering architecture for Service and Marketing AI capabilities. Lead the design of scalable, low‑latency backend systems and APIs that power our AI products and agents for 183K+ customers, handling billions of events and interactions. Build and harden AI serving systems. Lead the development of services that host and orchestrate AI models (LLMs, tools, evaluators, retrieval systems), with clear contracts, SLOs, and observability so other teams can depend on them. Evolve our agentic architecture. Drive the technical roadmap for Service and Marketing AI agents—improving tool use, autonomy, and reliability so agents can safely take actions on behalf of customers and internal users with minimal human intervention. Set engineering standards for AI services. Establish best practices for evaluation, safety/guardrails, prompt and model versioning, offline and online tests, and incident response for AI‑backed systems; hold the bar for design reviews and code quality. Lead cross‑team technical work. Act as the primary technical interface between Service / Marketing AI and other product/platform teams—clarifying ownership boundaries, aligning on interfaces, and unblocking dependencies across hubs and time zones. Mentor and uplevel engineers. Coach senior and mid‑level engineers through design, implementation, and operational best practices, helping them grow into stronger system owners and future tech leads. Help build the Palo Alto hub. Shape local engineering rituals, help with hiring and onboarding, and create healthy patterns for cross‑hub collaboration so work and career opportunities are not constrained by geography. Measure what matters. Define and track key metrics for your systems—availability, latency, cost‑to‑serve, agent success rates, eval scores, and customer adoption—and use those insights to drive roadmap and technical decisions. Transform engineering and product development workflows by putting AI at the center, building utilizing agentic coding tools and AI-first working. Who You Are Seasoned backend engineer tech lead. 8+ years of professional software engineering experience with a strong focus on backend and distributed systems; you’ve led complex projects or areas ... (truncated, view full listing at source)