Software Engineer II - Forms

Location: Boston

This job is with Klaviyo, an inclusive employer and a member of my Gwork – the largest global platform for the LGBTQ+ business community. Please do not contact the recruiter directly.

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.

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About the Role
Klaviyo is looking for a Full Stack Software Engineer II to join the  Signup Forms  team. On Signup Forms you’ll help rebuild and evolve one of Klaviyo’s core growth surfaces so brands can reliably capture high-intent profiles across web, SMS, and messaging channels.

The team is explicitly focused on improving reliability and developer experience while making leaps in both AI enablement and enterprise-level scale. This role is about delivering both the foundations and the pieces that unlock those higher-level platform capabilities.

As a Software Engineer II you’ll own non-trivial end-to-end pieces of the product: design and ship well-tested frontend and backend work, weigh trade-offs between reliability, performance, and developer velocity, and help make architectural decisions within the team’s roadmap. You’ll routinely tackle complex problems and deliver pragmatic, maintainable solutions that improve both customer outcomes and the team’s developer experience.

Within the organization, we focus on making experiences part of an extensible, channel-agnostic, enterprise-grade platform. That includes the web experiences, APIs, and backend orchestration that power validation, actions, and delivery alongside the analytics and data plumbing that connect form events to profiles and downstream messaging. You’ll partner closely with product, design, analytics, and other engineering teams to deliver best-in-class customer-facing experiences.

What We’re Looking For

A proven track record of building high-quality products and systems, with a focus on writing clean, maintainable code

3+ years of experience in a software engineering role

Experience building end-to-end software solutions or deep experience with both front-end and back-end technologies

Familiarity with code reviews and leading or participating in robust testing practices

Experience working in agile, fast-paced environments

Experience driving technical solutions in cross functional teams within an organization

Quick learners that can raise the team’s bar while

Nice to Have

Experience with React, Typescript and related technologies

Experience with Python and related technologies

Background in digital marketing or customer data software

Exposure to machine learning concepts or applications

Experience building cloud-native solutions, ideally on AWS

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…