Full-stack Software Engineer Co-op (Fall 2026)

Klaviyo Campus•Boston, MA

2d•$53 - $53•Onsite

About The Position

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. 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 are close but not an 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 Co-op At Klaviyo, our Engineering team builds the foundational technologies that power how brands grow through owned marketing. As a Full-stack Software Engineering Co-op, you’ll be part of a fast-paced, collaborative environment where your work directly impacts thousands of customers worldwide. You won’t just be writing code—you’ll be solving real problems, shaping user experiences, and learning from seasoned engineers across our engineering organization. This co-op is an opportunity to apply your software development skills in a production environment. You’ll be embedded within one of our engineering teams (see overviews below) and work on meaningful projects that make a real difference to our customers, all while building a strong technical foundation and connections across Klaviyo. Co-ops come to Klaviyo with experience in a variety of coding languages, but they are all passionate about building, owning, and scaling features end-to-end from scratch. You'll work alongside seasoned engineers, break through complex technical challenges, and gain hands-on experience contributing to real products that support Klaviyo's mission. We operate a real-time data platform coded in Python built for massive scale on Amazon Web Services (AWS). As an AI-first company you will be encouraged to use AI tools to support your work, accelerate learning, and succeed in your role.

Requirements

At least one previous software engineering internship/co-op with software development experience
Currently pursuing a degree in Computer Science, Engineering, Data Science, Math/Statistics or related field
Graduating in December 2026 or May/June 2027
Experience with some of these technologies and languages: Python, Django, Typescript, React MySQL, Cassandra, Clickhouse, Kafka, Redis Amazon Web Services (EC2, RDS, Aurora, etc.) Terraform
Enjoy working with new technologies ranging from the frontend to backend and adept at selecting the right tool for the job
Love digging into performance and scalability issues to drive breakthrough solutions-- whether it's a slow loading UI or too many clicks in a workflow, a database query timing out, or a queue that just won’t drain. You recognize all problems can be solved.
Enjoy shipping code early and often in an agile fashion, pairing with product management to craft better software by soliciting feedback from thousands of end-users
Embrace Klaviyo’s “always learning” culture that fosters learning at every level, constantly pushing yourself to be a better engineer
You’ve already experimented with AI in work or personal projects, and you’re excited to dive in and learn fast. You’re hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient.

Responsibilities

Own features that our 150K+ paying customers rely on daily to reach their consumers to drive their business forward
Be responsible for the mission, technical direction and operations of projects that have immediate impact
Architect and design robust and high performance data processing and storage systems leveraging new databases to serve different internal and external use cases
Craft our highly scalable real-time data pipeline that processes billions of events weekly across data sets growing to petabyte scale
Work on a deep analytics system that provides insight into hundreds of terabytes of data
Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up.