Senior Software Engineer

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.

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.

Customer Hub is an entrepreneurial team pioneering one of Klaviyo’s boldest bets: reinventing how ecommerce brands personalize the shopper journey. We’re bringing personalization on-site, building a unified account experience for shoppers across every touchpoint, and turning that into measurable conversion lift. As a nimble group with a 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.

• A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code.
• 5+ years of experience in a software engineering role.
• Strong experience developing end-to-end software solutions or extensive experience with both front-end and back-end technologies.
• Experience working with React and related technologies
• Experience leading projects and being accountable for their outcomes.
• Experience mentoring team members or driving initiatives that help the team learn new skills.
• Experience conducting code reviews and running a robust testing cycle.
• Experience working in agile, fast-paced environments.
• Experience using AI effectively in software development and delivery, leveraging AI tools to build smarter systems and ways of working from the ground up.

Nice to Have

• Skills with Python and Django web framework
• Experience working with Typescript
• Experience developing digital marketing or customer data software solutions.
• Experience building cloud-native solutions, ideally with AWS.

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.

We’re Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we’re developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators-ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you’re ready to do the best work of your career, where you’ll be welcomed as your whole self from day one and supported with generous benefits, we hope you’ll join us.