Senior Full Stack Engineer - Customer Agent

<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>&nbsp;to see how we empower creators to own their own destiny.</em></p></div><p><strong>About the Role</strong></p> <p>Our team is looking for a Senior Full Stack Engineer to lead key initiatives that will enhance our product offerings and support our company’s growth. In this role, you'll play a crucial part in shaping outcomes by developing innovative end-to-end solutions using both front-end and back-end technologies. You’ll optimize existing products and create new solutions that redefine what’s possible for our customers.</p> <p>As a Senior Engineer, you’ll tackle complex challenges, develop multiple solutions, and evaluate business and technical trade-offs to determine the best path forward. You’ll also act as a leader and mentor, and drive key technology decisions. Additionally, you’ll be responsible for deploying well-designed, thoroughly tested solutions that ensure reliability and performance.</p> <p>The Customer Agent team drives Klaviyo’s most ambitious innovations—creating and scaling the company’s boldest new bets. As a nimble group with a flat structure and fast-moving culture, we prioritize simplicity, speed, and impact. Every team member is expected to take radical ownership—rolling up their sleeves, collaborating across disciplines, and pushing beyond traditional role boundaries to make things happen. Success in this role means delivering exceptional work that sets the standard for velocity and results company-wide, while helping shape Klaviyo’s future through experimentation, creativity, and executional excellence.</p> <p><strong>What We’re Looking For</strong></p> <ul> <li>A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code.</li> <li>7+ years of experience in a software engineering role.</li> <li>Strong experience developing end-to-end software solutions or extensive exp