Senior Software Engineer - Growth

## Responsibilities - Drive the technical design and lead the implementation of high-impact user-experience improvements across the Klaviyo product, focusing on areas critical to new customer success and adoption. - Own the end-to-end experimentation process, including contributing to the definition of strategy, architecting and implementing A/B tests to validate product hypotheses, and interpreting data to drive significant iterative improvements. - Serve as a technical leader and liaison, collaborating proactively with partners across teams to define and prioritize key technical initiatives to shape the long-term product roadmap. - Take a lead role in mentoring and providing technical guidance to other engineers on the team, elevating our experimentation, development, and operational practices. - Define the architectural approach and technical strategy for your area of responsibility, anticipating scalability and reliability needs, including leveraging AI agents in our work and delivery. - Working from our Boston HQ at least three days a week. ## Requirements - Have an extensive background in full stack software engineering, demonstrating deep understanding of Klaviyo’s systems and the ability to architect, deliver, and maintain software with an emphasis on high-scale, user-facing features, and their supporting APIs and infrastructure. - Demonstrated ability to drive technical strategy and improvement using a data-driven mindset, leading to measurable business results and upholding best practices. - Demonstrated technical experience in using and championing AI-driven software delivery practices and methods, a passion for continuous learning and mentoring, and the ability to work productively through others to set them up for project success. - Experience driving A/B testing strategies for products with metric-based goals to significantly improve user experience, customer acquisition, and success is a strong plus. - Thrives in an entrepreneurial type environment that is customer focused and strategic, while bringing clarity and technical stability to ambiguous challenges and prioritizing work that enables the team to move faster. ## Nice to Have - Experience driving A/B testing strategies for products with metric-based goals to significantly improve user experience, customer acquisition, and success. ## Benefits - The opportunity to work on a high-impact team focused on improving the customer onboarding experience. - A collaborative and innovative work environment that values diverse perspectives and backgrounds. - The chance to work with cutting-edge technologies and AI-driven software delivery practices. - A chance to contribute to the long-term product roadmap and shape the future of Klaviyo's platform.