Data Science Internship - Summer 2025

Klaviyo is growing fast and we have openings for all skill levels across data science. Listen to our data science team podcast at https://medium.com/klaviyo-data-science and learn more about our technical culture at https://klaviyo.tech

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 careers.klaviyo.com to see how we empower creators to own their own destiny.

About our internship

Our Data Science Internship is designed to provide each intern meaningful and robust projects that directly impact our product and customers. The internship program is small, allowing interns at Klaviyo the opportunity to form a tight-knit group who get to bond with each other over the course of the summer.

Interns dive into substantial projects, making a tangible impact during the course of the summer. Projects have concrete goals and objectives but allow plenty of room for exploration and problem solving. Past successful projects include: modeling non-compliant content (e.g. phishing) in emails, forecasting SMS usage by customers, building a recommendation system for courses on our Academy site. We offer a supportive environment where interns can test, fail, iterate and launch while building a solid technical foundation, awesome connections across Klaviyo and have fun.

Data Science Interns come to Klaviyo with quantitative backgrounds, experience programming in Python and an interest in doing everything from exploratory analysis to training and deploying models. At Klaviyo we use a wide variety of data mining, machine learning algorithms and generative AI techniques. We’re focused on shipping early and often. We prefer iterative solutions that are incrementally better to the perfect solution.

How you’ll make an impact

• Take on a project that will make a meaningful, real impact for Klaviyo users or internal company stakeholders
• Build data science-powered features that our customers love and help them grow faster. Examples of features we’ve added to Klaviyo: A/B testing, personalized product recommendations, and creative assistance.
• Use data science to help Klaviyo grow faster. This includes building smart algorithms to automate processes that are currently manual, performing analyses to help our internal teams know how to best target their resources, and building predictive models to better understand our customers and business.
• Analyze large data sets (we’re collecting billions of individual actions every month)

What We’re Looking For

• At least one previous software engineering internship/co-op with software development experience
• Graduating in December 2025 or May/June 2026
• Possess a strong fundamental understanding of at least some machine learning algorithms (e.g. regressions, decision trees, k-means clustering, neural networks).
• Capable of analyzing data and making rigorous statements about what can or cannot be concluded.
• Know how to design and implement model performance/validation assessments.
• Have an understanding of statistics and understand different distributions and the conditions under which they’re valid.
• Know how to code and have used data science tools and packages.
• Have a desire to ship features powered by data science (in other words, you’re excited by both upfront research and actually getting models into production at cloud scale); OR
• Have a desire to work directly with business stakeholders to create tools that will provide insight and make them more efficient.
• Pursuing a degree in statistics, applied mathematics, computer science or other relevant quantitative discipline.

Internship Logistics

• Our Summer Internship Program is a 11-week (June 2 - August 15) paid experience at our Boston, MA headquarters
• Before diving into individual teams and projects, all interns will complete Klaviyo Base Camp - a week-plus onboarding experience. Base Camp provides focused time to learn about Klaviyo, our product, the ins and outs of engineering and spend time getting to know other interns. This robust training experience ensures all interns join their teams fully prepared to dive into project work and make an immediate impact.
• Our Boston office is fun - our interns stay fueled with free snacks and drinks, take breaks with each other over a game of ping pong, nintendo or round of golf with our simulator, and relax in our speakeasy (yes you read that right!).
• Throughout the summer, Klaviyo interns attend social events to promote interaction beyond team and project work. In past years these events have included a Red Sox game, Boston Duck Tour, outings to SPIN and Flight Club in the Boston Seaport, ice cream socials, and Munch n Learns with Klaviyo senior leadership.
• Priority application deadline: October 11th