Lead AI Software Engineer

<div class="content-intro"><p><em>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 <a class="_ymio1r31 _ypr0glyw _zcxs1o36 _mizu194a _1ah3dkaa _ra3xnqa1 _128mdkaa _1cvmnqa1 _4davt94y _4bfu18uv _1hms8stv _ajmmnqa1 _vchhusvi _kqswh2mm _ect4ttxp _syaz13af _1a3b18uv _4fpr8stv _5goinqa1 _f8pj13af _9oik18uv _1bnxglyw _jf4cnqa1 _30l313af _1nrm18uv _c2waglyw _1iohnqa1 _9h8h12zz _10531ra0 _1ien1ra0 _n0fx1ra0 _1vhv17z1" href="http://klaviyo.com/careers" data-renderer-mark="true">klaviyo.com/careers</a> to see how we empower creators to own their own destiny.</em></p></div><h2><strong>Lead AI Engineer</strong></h2> <p>At Klaviyo, we believe the future of software lies not in productivity tools for human users but in <strong>systems that can learn, run, and optimize themselves</strong> based on measurable outcomes. We’ve built the infrastructure and applications that power the interface between businesses and consumers — supporting over <strong>182,000 customers</strong>, <strong>billions of consumer profiles</strong>, and <strong>hundreds of billions of customer interactions</strong>.</p> <p>Now, we’re building the next generation of <strong>AI and machine learning technologies</strong> to power these products — enabling AI agents that can automatically create, execute, and optimize marketing and customer experience strategies for any business.</p> <p>As a <strong>Lead AI Engineer</strong>, you’ll take ownership of designing, building, and scaling the backend and machine learning systems that form the foundation of Klaviyo’s AI strategy. You’ll partner closely with product managers, data scientists, and engineers to deliver intelligent, outcome-driven systems that operate at massive scale — while mentoring others and setting technical direction for the team.</p> <h3><strong>How You Will Make a Difference</strong></h3> <ul> <li><strong>Lead the design and development</strong> of backend and ML systems that scale to serve 182K+ customers.<br><br></li> <li>Build <strong>robust, reliable, and efficient data processing and model-serving pipelines</strong> that power production ML models.<br><br></li> <li>Develop and optimize <strong>predictive systems</strong> (e.g., conversion likelihood, engagement ranking, personalization, anomaly detection).<br><br></li> <li><strong>Architect systems and services</strong> that enable our AI agents to learn and improve autonomously from reward or outcome signals.<br><br></li> <li>Collaborate cross-functionally to translate business challenges into <strong>scalable, measurable ML solutions</strong>.</li> <li> </li> <li>Collaborate with software engineers and product managers to turn predictive models into intuitive product features for our customers.<br><br></li> <li>Mentor engineers and help evolve Klaviyo’s <strong>ML engineering best practices, tooling, and architecture</strong>.<br><br></li> <li>Foster a culture of <strong>ownership, experimentation, and data-driven innovation</strong> across teams.<br><br></li> </ul> <h3><strong>Who You Are</strong></h3> <ul> <li>7–10 years of experience in <strong>machine learning engineering or applied software engineering</strong>, with a focus on <strong>classical ML and predictive modeling</strong>.<br><br></li> <li>Deep understanding of <strong>supervised learning methods</strong> such as random forests, XGBoost, logistic regression, and ensemble techniques.<br><br></li> <li>Proven track record of building and scaling <strong>production-grade ML systems</strong> end to end (data pipelines, training, deployment, and monitoring).<br><br></li> <li>Experienced backend engi ... (truncated, view full listing at source)