Senior Software Engineer, Composer AI Product

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.

About the Role

The Klaviyo Composer team is building the foundation for how Klaviyo customers plan, create, edit, and iterate on their marketing strategy through an in‑app, AI‑powered conversational experience. We own the native chat surface, the agent orchestrator, and the agentic UI framework that other teams across Klaviyo will plug into.

By joining the Klaviyo Conversational AI Platform team, you will have the opportunity to have a direct impact on over 170,000 brands that use Klaviyo every day to engage with their customers. You’ll also help define and build Klaviyo’s Autonomous Marketing platform: an ecosystem of LLM‑powered agents that can analyze, create, and optimize marketing programs across campaigns, flows, forms, and more.

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.

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.

What We’re Looking For

• A proven track record of building high-quality products and systems, with pride in writing clean, maintainable, high-quality code.


• 7+ years of experience in a software engineering role.


• Strong experience developing end-to-end software solutions or extensive experience across both front-end and back-end technologies.


• Experience building scalable, customer-facing systems in fast-moving product environments - we operate like a startup inside of Klaviyo.


• Experience leading projects and being accountable for technical and business outcomes.


• Experience mentoring team members or driving initiatives that help the team grow and learn new skills.


• Experience conducting code reviews and maintaining a robust testing and deployment cycle.


• Curiosity and enthusiasm for AI-native product development, including practical experience experimenting with LLMs, AI tooling, or agentic workflows in professional or personal projects.


• Excitement about leveraging AI to improve engineering velocity, customer experiences, and operational workflows.


• A strong product mindset and willingness to collaborate cross-functionally to solve ambiguous problems with urgency and pragmatism.

Nice to Have

• Skills with Python and related technologies.


• Skills with React and related technologies.


• Experience building conversational AI systems, workflow engines, or agentic platforms.


• Experience with retrieval systems, embeddings, eval frameworks, or LLM orchestration patterns.


• Experience building cloud-native solutions, ideally with AWS.


• Experience developing customer support, commerce, marketing, or customer data software solutions.


• Experience with machine learning systems or AI infrastructure.


• Experience building multi-tenant or highly configurable SaaS platforms.


• Familiarity with observability, tracing, experimentation, or AI quality/evaluation tooling.