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The Amplify Engineering team builds the internal tools, platforms, and AI-powered automation that help Klaviyos work more efficiently and at scale as the company grows. We partner across the organization, including Sales, Marketing, Engineering & Product, and Customer Service & Success, to solve real operational problems with practical, well-designed software.

Our work spans internal applications, 3rd-party integrations, interactive dashboards, CMS integrations, and robust AI systems and agents that automate repetitive tasks, surface the right information at the right time, and help teams make better decisions. We operate in tight feedback loops with our internal customers, shipping quickly, learning fast, and seeing the impact of our work immediately in how deals move faster, tickets resolve sooner, and launches go more smoothly.

This role is for senior technical leaders who own hard problems end-to-end across multiple domains, set the technical bar for how Amplify builds, and drive engineering excellence across the broader organization. The work is highly visible and has a direct impact on how thousands of Klaviyos get their work done every day.

The Amplify team builds the internal platforms, automation, and AI-driven systems that power how Klaviyos work every day. As a Senior Lead Software Engineer on Amplify, you will:

• Independently own and drive high-impact objectives that span multiple Amplify teams and align with company priorities, defining the technical roadmap that ensures our internal applications, APIs, data and event pipelines, and AI-powered workflows can scale with Klaviyo and continue delivering measurable business outcomes.
• Be accountable, in partnership with Engineering Managers, for the long-term technical health of Amplify's systems - quality, reliability, scalability, cost, and security - across a significant slice of Klaviyo engineering, maintaining strong system-level thinking across interconnected internal platforms.
• Independently lead the end-to-end lifecycle of large, multi-team initiatives with clear technical direction, architectural leadership, and active workstream curation, from discovery and design through implementation, rollout, and long-term ownership of complex programs that span internal customers across the company.
• Make high-judgment architectural calls in ambiguous situations, committing decisively even when facing disagreement, and use prototypes and reference implementations to de-risk decisions before broader investment.
• Establish shared standards, patterns, and reference implementations that multiply team effectiveness across Amplify and adjacent engineering teams, and proactively redirect efforts away from low-leverage approaches and toward higher-impact solutions when projects are off-course.
• Define and communicate forward-looking technical strategy that integrates input from Product, Design, Data, and operational partners, and use that strategy to lead technical discussions and influence the roadmaps of adjacent teams whose work intersects with Amplify.
• Set the standard for AI-native engineering at Amplify. Use modern AI tools - coding assistants, agentic workflows, RAG pipelines, and evaluation harnesses - as a core part of your day-to-day workflow, define guardrails for building AI-powered systems responsibly, and help the broader engineering organization adopt AI effectively in design, coding, testing, and operations.
• Own the response to complex performance, scalability, and reliability issues across Amplify systems, working side by side with teams in the trenches during incidents, owning mistakes, and turning post-incident learnings into changes that prevent recurrence and raise the bar across the organization.
• Define and own the operational standards Amplify holds itself to, including SLOs, monitoring and alerting, incident response, security, observability, and cost, and continuously evolve them as usage and complexity grow.
• Get work done primarily through influence, delegation, and clarity, providing clear technical direction and creating the patterns, platforms, and de-risked references that let dozens of engineers across Amplify move quickly and safely.
• Invest in the growth of engineers across levels at Amplify, with a particular focus on developing emerging Senior and Lead engineers through design reviews, pairing, RFC feedback, and intentional one-on-one coaching, and participate actively in senior engineering hiring to represent Klaviyo's technical challenges and culture.
• Connect technical work to customer outcomes and business objectives, ensuring Amplify is investing in the highest-leverage opportunities and that engineering practices advance with measurable, multiplicative impact across the organization.

• You are passionate about building software effectively and for the long term, balancing technical quality, velocity, and business impact, and you are comfortable making and explaining trade-offs at that intersection across multiple teams.
• BA or BS Degree in Computer Science, related field, or equivalent experience.
• 12+ years of experience in software development with deep knowledge of computer science fundamentals, domain-driven design, and architectural patterns for distributed, multi-tenant systems.
• You bring deep expertise in a core problem space - internal platforms, full-stack or backend SaaS systems, data and event pipelines, web applications, or AI-enabled systems - and you maintain strong system-level thinking across interconnected areas.
• You have independently led delivery of large, multi-team programs spanning multiple quarters, including discovery, design, implementation, rollout, and ongoing ownership, and have a track record of breaking through technical obstacles and leading teams through crises by working alongside them in the trenches.
• You are comfortable making high-judgment architectural calls in ambiguous situations and committing decisively even when facing disagreement, and you use prototypes and reference implementations to de-risk decisions before broader investment.
• You have demonstrated experience defining technical strategy and roadmaps that align with company priorities, integrating input from cross-functional partners, and influencing the roadmaps of adjacent teams whose work intersects with yours.
• You have a track record of redirecting teams from low-value approaches toward higher-leverage solutions, and of building patterns, processes, and reference implementations that multiply team effectiveness with measurable, multiplicative impact.
• You are an AI-native engineer and leader. You regularly use modern AI tools - coding assistants, LLM APIs and SDKs, agentic workflows, RAG pipelines, and evaluation harnesses - to accelerate your engineering workflow, you have practical experience building or integrating AI-powered systems, and you are excited to set the standard for how an organization adopts AI thoughtfully and responsibly.
• You take direct ownership of operational excellence for the systems your teams build, including performance, reliability, observability, security, cost, and on-call, and you are comfortable defining SLOs, leading incident response, and owning RCAs end-to-end.
• You are highly effective at working through influence and delegation. You provide clear technical direction, create the clarity, patterns, and guardrails that let a large group of engineers move quickly and safely, and you are an exceptional communicator across technical and non-technical audiences.
• You own mistakes openly, take action to prevent recurrence, and share learnings broadly so the wider organization benefits from what your team has learned.
• You are passionate about mentorship and have direct experience growing senior engineers and leads, including emerging Seniors and Leads, through design reviews, technical coaching, and creating opportunities for others to step up. You participate actively in senior engineering hiring.
• You enjoy questioning convention and continuously improving how things work - architecture, tooling, workflows, or processes - and you know how to introduce change while bringing people along with you.
• You enjoy working in small, autonomous, agile teams, shipping incrementally, and partnering closely with product, data, and design partners to deliver better outcomes for internal customers.

• Deep experience building internal tools, developer platforms, or operations automation, with measurable impact on reliability, productivity, or operational efficiency across multiple teams.
• Practical experience building or integrating production AI systems and agents, including workflows using LLM APIs and SDKs, agentic or automated workflows, RAG pipelines, evaluation harnesses, and monitoring frameworks for AI systems.
• Experience designing and operating large-scale services on AWS with infrastructure as code (Terraform) and containerized environments (Kubernetes), including capacity planning, cost optimization, and disaster recovery.
• Experience partnering closely with go-to-market, customer service & support, finance, or operations leaders to translate complex workflows into internal tools that drive measurable efficiency and business outcomes.

Klaviyo's platform is primarily built with Python and React and runs on AWS. Engineers join us from a wide range of technical backgrounds and are supported in learning our stack. Core technologies include:

• Python / Django / FastAPI
• TypeScript / React
• MySQL / Redis / Memcached
• RabbitMQ / Celery / Apache Kafka / Apache Pulsar
• AWS / Terraform / Kubernetes
• AI: Anthropic, OpenAI, and Google Models. Claude Code & Cursor

This role is based in Boston, Massachusetts and follows a hybrid working model. Klaviyo supports work authorization and relocation for this position.

At Klaviyo, we enjoy tackling meaningful engineering challenges and value people who take ownership, learn continuously, and collaborate openly. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds.

Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at https://klaviyo.tech