Senior Software Engineer - Adoption Team

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.

Why You Should Join the Adoption Team 

The Adoption team at Klaviyo is focused on enabling our customers to see more value by adopting additional features and products (e.g., SMS, CDP, Reviews, Push, Integrations, etc.). We work diligently to improve the rate at which customers are successfully activating new channels and gaining value from all aspects of the Klaviyo platform. Engineers on the Adoption team use data to discover opportunities for improvement, implement A/B tests to validate ideas, and work across the product to iteratively improve UX and educate customers. We are looking for great generalist software engineers with a focus on the frontend that have an interest in or experience with growing a user-base and building polished user-facing features.

How You Will Make a Difference 

• In this role, you will implement user-experience improvements across the Klaviyo product.
• You will design and implement A/B tests to validate ideas, and interpret the results of A/B tests to inform iterative improvements to the product.
• You will collaborate with marketing, data science, sales, and engineering teams to discover areas for improvement, as well as engaging with customers directly to learn more about how we can better serve their needs.
• You will help us improve our development processes and mentor other engineers on the team.
• You will work from our Boston HQ at least three days a week.

Who You Are 

• Experienced in technical leadership and seeing large projects through to completion.
• Have a strong background in full stack software engineering with experience building and improving products, with particular emphasis on the frontend.
• Skilled at reading and understanding code, across a variety of codebases.

• Enjoy working with new technologies ranging from the frontend to backend, and are particularly passionate about and an expert in multiple stack areas. You show this by having strong and opinionated experience with various technologies and know how to pick the right tool for any job.
• Passionate about growing and improving a product daily using a data-driven mindset.
• Thrive in a startup/entrepreneurial type environment that is fast paced, customer focused, and strategic.
• Experienced with A/B Testing products with metric based goals to improve user experience and customer acquisition and success (nice to have)

Technologies we use (not exhaustive):

• HTML, TypeScript, JavaScript, React
• Python, Django, Celery
• MySQL, Cassandra, RabbitMQ, Redis
• Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform, Ansible, Packer, and other DevOps tools

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. Please