Senior Staff Engineer

Who you are

• We are just beginning to unlock what is possible, and we are looking for an engineering leader who is eager to define that future
• 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
• 10+ 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
• 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 0→1 products or working in startup environments

What the job involves

• Are you looking for one of the most impactful AI-native leadership roles in Boston? Join us at Klaviyo and lead the team building 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're past the demo stage: the team ships changes against live customer traffic, measures quality with real evaluation frameworks, and treats reliability as a product feature, not an afterthought
• We are seeking an experienced Senior Staff 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
• 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
• 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
• 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

Benefits

• Private medical insurance
• Medical
• Dental
• Vision
• Lifestyle spending account
• Commuter benefits
• Modern Health - wellness platform
• Parental leave
• Company equity
• Employee stock purchase plan
• Health savings account (HSA)
• Flexible spending accounts (FSAs)
• Employee assistance program (EAP)
• 401(k) plan with company match
• Flexible paid time off (FPTO)
• 13 company holidays
• Paid parental bonding leave
• Medical, Dental, Vision
• Pension
• Financial coaching
• Life insurance
• Income protection
• Annual leave - up to 25 annual leave days
• 10 company holidays (8 bank holidays + 2 recharge days)
• Family leave
• Cycle to Work benefit
• Mental health benefits