Software 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 Software Engineer
Location: Boston, MA

This role is based in our Boston hub. We operate a hub‑first model, with regular in‑office collaboration expected.

About the Role

At Klaviyo, we believe the future of software isn’t just better productivity tools for humans—it’s intelligent systems that can run, optimize, and adapt themselves based on real-time outcome and reward signals. Having already built the infrastructure and applications that connect businesses with over 200,000 customers, billions of consumer profiles, and hundreds of billions of interaction events, we are now making foundational investments in Marketing AI and Service AI to power next-generation agentic capabilities across our entire ecosystem.

The Klaviyo Orchestrate pillar drives the core platform experience, providing the high-throughput capabilities our customers use daily to manage and execute complex marketing workflows. This team balances strict Tier-1 availability and low-latency scalability requirements with rapid agility across the Klaviyo ecosystem. Internally, we have fully embraced AI-native engineering methodologies and are dedicated to putting sophisticated AI-native capabilities directly into the hands of our builder-customers.

We are building a best-in-class, flexible orchestration platform designed to handle massive scale while continuously advancing reliability and performance to meet the expanding needs of our global customer base.

How You’ll Make a Difference

• Architect and scale Klaviyo’s Core Orchestration platform, supporting high-traffic, low-latency services with extreme reliability.
• Drive the technical vision for integrating AI-driven agentic workflows and automated decision-making into core customer interactions.
• Lead the adoption of AI-native software development practices, continually improving engineering productivity and delivery speed across the team.
• Design foundational frameworks and services adopted across engineering teams, championing high technical standards through design reviews and mentorship.