Senior Software Engineer - Profiles, Lists and Segments

United States Digital Space LLC; Boston (MA); On-site; USD 148,000 - 222,000; Full time

Job summary

United States Digital Space LLC is seeking a Senior Software Engineer for the Profiles, Lists and Segments team. You will design and build scalable systems powering customer data experiences, focusing on thoughtful frontend components using TypeScript, React, and Python/Django.

You will collaborate with product managers, data scientists, and other platform teams to translate complex problems into practical implementations, with opportunities for growth in a central product area of the company.

Qualifications

• 5+ years of experience in full-stack development with React, Redux, JavaScript, HTML, and CSS.
• Experience with RESTful and GraphQL APIs and evolving APIs and data models.
• Experience conducting code reviews and automated testing (e2e/integration tests).
• Ownership of requirements, edge cases, implementation and testing, with cross-team collaboration.

Responsibilities

• Design and build scalable front-end and back-end components for data experiences (profiles, lists, segments).
• Collaborate with Product, Design, and Data Science to deliver the best user experience.
• Mentor teammates and drive initiatives to learn new skills across the team.
• Deliver features with attention to performance and reliability across large datasets.

Skills

React

Redux

JavaScript

HTML

CSS

RESTful APIs

GraphQL

Tools

AWS

Terraform

MySQL

RabbitMQ

Redis

ProxySQL

Python

Django

Job description

*At the company, we value the unique backgrounds, experiences and perspectives each the company (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 the company? Visit the company.com/careersto see how we empower creators to own their own destiny.

Why You Should Join the PLS (Profiles, Lists and Segments) Team:

The PLS team is responsible for building and scaling the core customer data experiences at the company —profiles, lists, and real-time segments. We own the tools that let customers understand who their users are, group them into meaningful audiences, and keep those audiences up to date as new data flows in. Our work underpins how customers target, personalize, and measure every message they send, making this product area core to the company’s continued success.

As a Senior Software Engineer on the team, you’ll play a key role in designing and building scalable systems that power how customers manage and activate their data. Partnering closely with product managers, data scientists, and other platform teams, you’ll help define scope, translate complex data and UX problems into practical implementations, and build intuitive workflows that give customers confidence in their audiences. This role leans frontend, with a strong focus on crafting thoughtful, reusable components and seamless user experiences using technologies like TypeScript, React, Python, and Django. There are ample opportunities for growth given the scope of this role and the team’s central role in the company’s product.

How You Will Make a Difference:

• You will be a core member of the PLS team, working on impactful customer-facing features that will make our product the best in the industry.

• You will work on creating easy-to-use editors that are highly performant.

• You will work closely with Product, Design, and Data Science to provide the best experience for our customers.

• You will mentor team members and drive initiatives that help the team learn new skills.

Who You Are:

• 5+ years of experience in full-stack development with strong hands-on skills in React, Redux, JavaScript, HTML, and CSS, along with familiarity with general web best practices.

• Has a track record of delivering and shipping work powered by or accelerated through AI.

• Experience conducting code reviews and running a robust testing cycle using automated testing practices and frameworks, including end-to-end and integration tests (e.g., cypress, pytest).

• Experienced with RESTful and GraphQL APIs, and evolving APIs and data models to support product success.

• You take ownership of your work—from requirements and edge cases to implementation and testing—and are motivated by solving tough problems with others.

• Proven track record of leading complex, multi-quarter projects involving cross-team collaboration and being accountable for their outcomes

Technologies We Use (not exhaustive):

• React, TypeScript, Redux

• Python, Django

• Amazon Web Services (EC2, RDS, Aurora, S3, etc.), Terraform, and other DevOps tools

• MySQL, RabbitMQ, Redis, ProxySQL

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:

$148,000—$222,000 USD

*This role may require up to 10% travel for purposes such as new hire onboarding, client or partner work if applicable, team meetings, and industry events. Travel is coordinated in advance.

Get to Know the company

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

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

*the company is committed to a policy of equal opportunity and non-discrimination. We do not*