Senior Software Engineer

Klaviyo•Boston, MA

2d•$148,000 - $222,000

About The Position

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.

Requirements

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
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
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 Haves

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

Responsibilities

Tackle complex technical and product challenges
Develop multiple solution paths
Evaluate business and architectural trade-offs to determine the best approach
Act as a technical leader and mentor
Drive engineering quality, execution, and decision-making across projects
Deploy well-designed, thoroughly tested solutions that prioritize reliability, scalability, and customer impact
Ship high-quality systems quickly
Contribute to foundational platform decisions
Improve the intelligence and reliability of our agent experiences
Help define how AI-powered customer engagement evolves at Klaviyo
Conduct code reviews
Maintain a robust testing and deployment cycle