Software Engineer II - Custom Objects

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Software Engineer II – Custom Objects Platform

Background

Klaviyo operates a real-time data platform built for massive scale, powering segmentation, automation, analytics, and personalization for hundreds of thousands of customers. At the core of this platform are three foundational data entities: Profiles, Events, and Objects.

The Custom Objects team owns the platform that allows customers to define, store, and evolve their own domain-specific data models — enabling richer personalization, advanced segmentation, and flexible analytics beyond Klaviyo’s built-in data types.

As a Software Engineer II on the Custom Objects team, you’ll help build and scale the systems that allow customers to safely model, query, and activate their custom data at scale.

How You’ll Make an Impact

Custom Objects unlock how customers represent their business inside Klaviyo.

In this role, you’ll:

• Build systems that support customer-defined schemas and flexible data models

• Enable other teams (Flows, Segmentation, Analytics, AI) to safely rely on object data

• Work on platform primitives that must balance flexibility, correctness, performance, and cost

• Contribute to a core data surface that directly impacts customer experience and product velocity

What You Will Do

• 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

What We’re Looking For

Required Qualifications

• 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

Nice to Have

• 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

What Success Looks Like

In the First 90 Days

• Develop a strong understanding of Klaviyo’s data model and platform architecture

• Contribute meaningful code to production systems

• Learn how custom objects interact with Events, Profiles, and downstream consumers

• Participate effectively in design and code reviews

Over the First Year

• Own medium-sized features or system improvements end-to-end

• Improve reliability, performance, or usability of the Custom Objects platform

• Demonstrate strong judgment around data modeling and tradeoffs

• Be a reliable on-call contributor and teammate

• Help raise the overall engineering bar through thoughtful reviews and collaboration

Why This Role Is Unique

• You’ll work on customer-defined data, one of the hardest classes of platform problems

• You’ll solve challenges around schema evolution, correctness, and scale

• Your work will directly impact how customers model their business and activate their data

• You’ll gain deep experience in platform engineering at the heart of Klaviyo’s data systems

We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025.

Please see the independent bias audit report covering our use of Covey here

Massachusetts Applicants:
It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant’s job-related skills, relevant experience, education or training, and work location.

In addition to base salary, our total compensation package may include participation in the company’s annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.

Base Pay Range For US Locations:
$116,000—$174,000 USD

Get to Know Klaviyo

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.

AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed.

By participating in Klaviyo’s interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice.

Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law.

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