Software Engineer II - Custom Objects

Job Summary: Klaviyo is a company that empowers creators to own their destiny by making first-party data accessible and actionable. They are seeking a Software Engineer II for their Custom Objects team to build and scale systems that enable customers to define and manage their own data models, enhancing personalization and analytics capabilities. Responsibilities: • Design, build, and maintain services that power the Custom Objects platform • Implement APIs and data pipelines for creating, updating, and querying custom object data • Work with evolving schemas while maintaining backwards compatibility and data integrity • Collaborate with Product, Events, Profiles, and Analytics teams to integrate custom objects into the broader platform • Debug and improve performance of data-heavy systems operating at scale • Participate in code reviews, design discussions, and on-call rotations • Contribute to improving operational excellence through better observability and tooling Qualifications: Required: • 3–6 years of professional software engineering experience • Experience building backend systems in a production environment • Strong fundamentals in data structures, algorithms, and system design • Experience working with databases or data storage systems (relational or distributed) • Ability to reason about correctness, tradeoffs, and edge cases in stateful systems • Strong communication skills and comfort working with cross-functional partners Preferred: • Experience with schema-driven or user-defined data models • Familiarity with distributed systems and high-throughput services • Experience working with Python or similar backend languages • Exposure to cloud infrastructure (AWS preferred) • Experience supporting both online and analytical workloads Company: Klaviyo is an automation and email platform designed to help grow businesses. Founded in 2012, the company is headquartered in Boston, USA, with a team of 1001-5000 employees. The company is currently Late Stage.

Created: 2026-03-07