Senior Lead Engineer, Customer Agent

Are you looking for one of the most impactful AI-native engineering roles in Boston? Join us at Klaviyo and help build Customer Agent, a conversational AI system that enables brands to interact with their customers at a scale they have never achieved before.

Customer Agent is central to Klaviyo's vision for AI-powered customer engagement. It delivers real-time, contextually aware conversations that help brands support, convert, and retain millions of consumers. We are just beginning to unlock what is possible, and we are looking for a senior technical leader who is eager to define that future.

We are seeking an experienced engineer with deep expertise building and scaling agentic systems and AI-enabled products. You will shape how Customer Agent evolves into a highly extensible, reliable, and intelligent platform. You will drive technical strategy, lead architectural direction, and partner closely with product, design, data science, and engineering leaders to deliver industry-defining AI experiences.

This role is ideal for a hands-on technical leader who thrives in ambiguity, enjoys building from first principles, and wants to influence both product direction and engineering strategy. You will be expected to operate as a force multiplier across teams, leading through technical excellence, execution, and mentorship rather than direct people management.

You will work on some of Klaviyo's most important AI investments, helping define the next generation of conversational experiences while operating at the intersection of large-scale systems, agentic workflows, personalization, and real-world customer outcomes.
How You Will Make a Difference

• Lead the architecture, design, and implementation of Customer Agent's core platform and AI capabilities.
• Drive technical strategy and long-term system evolution for conversational AI experiences serving millions of users.
• Build and ship complex AI-powered product features, balancing speed, quality, reliability, and customer impact.
• Partner closely with Product, Design, Data Science, GTM, and Engineering leaders to define product direction and execution plans.
• Make critical technical decisions around agent architectures, orchestration frameworks, retrieval systems, memory, tool use, evaluation, and reliability.
• Establish engineering best practices around observability, testing, monitoring, experimentation, and operational excellence for AI systems.
• Lead large, cross-functional initiatives spanning multiple teams and organizations.
• Mentor engineers through technical leadership, design reviews, architecture discussions, and hands-on collaboration.
• Evaluate emerging AI technologies and frameworks, identifying opportunities to create meaningful customer value.
• Influence engineering standards and contribute to the broader technical direction of Klaviyo's AI platform.

Who You Are

• 12+ years of software engineering experience building and operating production systems at scale.
• Significant experience designing and shipping customer-facing AI-powered products or agentic systems.
• Strong backend engineering and distributed systems fundamentals, with the ability to reason about scale, latency, reliability, and operational tradeoffs.
• Demonstrated expertise with modern AI architectures, including LLM-powered applications, retrieval systems, agent workflows, orchestration, evaluation frameworks, and guardrails.
• Proven ability to lead complex, multi-quarter technical initiatives involving multiple teams and stakeholders.
• Strong product instincts and the ability to connect technical decisions to customer and business outcomes.
• Comfortable operating in ambiguous, fast-moving environments and defining direction when requirements are incomplete.
• Excellent communication and collaboration skills across engineering, product, design, and executive audiences.
• Hands-on builder who enjoys working directly in code and tackling difficult technical problems.
• Track record of influencing engineering organizations through technical leadership, mentorship, and execution excellence.

Bonus Points

• Experience building conversational AI, customer support automation, or agentic workflow platforms.
• Experience with production evaluation systems, AI observability, human-in-the-loop workflows, and reliability engineering for LLM-powered products.
• Experience building 01 products or working in startup environments.
• We love recovering entrepreneurs. If you've ever run your own thing, you'll have company on our team.

Boston, MA - In-Office Role

Massachusetts Applicants:It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location.

In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.

Base Pay Range For US Locations:

$216,000-$324,000 USD

This role may require up to 10% travel for purposes such as new hire onboarding, client or partner work if applicable, team meetings, and industry events. Travel is coordinated in advance.