Klaviyo
Software Engineer II, Integrations Velocity (Fullstack – Frontend lean)
Job Description
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.
Klaviyo’s Integrations Velocity team is building the future of how integrations are created and maintained—not just by our internal engineers, but by developers across the Klaviyo ecosystem. We currently support dozens of integrations supporting over 149,000 customers across 80+ countries. As Klaviyo expands beyond e-commerce into new industries, we want to make integrations faster to build, easier to maintain, and more accessible to developers everywhere.
To support this, we built the Integrations Generation Framework (IGF)—a Python-based, declarative ETL engine that powers all new integrations through a unified codebase. IGF dramatically reduces complexity by centralizing monitoring, error handling, and sync logic, while enabling integrations to be defined declaratively.
As a Software Engineer II on this team, you’ll work across the stack—but with a strong focus on frontend development. You’ll help design and build intuitive React-based tools and UIs that streamline the development experience for anyone working with IGF. From debugging and deployment to monitoring and configuration, your work will directly improve how fast and efficiently new integrations are delivered.
You’ll also collaborate on our Python backend, contributing to the continued evolution of IGF and the infrastructure that powers it. Whether you're writing reusable components, improving observability, or building documentation workflows, your contributions will help accelerate Klaviyo’s ability to enter new markets and scale developer impact.
What You’ll Do
- Build React applications and components that improve the integration development experience (debugging tools, visual monitoring, etc.)
- Collaborate on IGF’s Python-based backend, contributing to core ETL workflows and developer APIs
- Help define the user experience for internal and external developers working with integrations
- Own your projects end-to-end, writing well-tested, maintainable code and participating in technical design
- Partner closely with Product, Design, and other engineers to ship impactful features that scale
What We’re Looking For
- 4+ years of experience in a software engineering role with a strong focus on frontend development
- Strong proficiency in React 16+, Javascript/Typescript, HTML, and CSS
- Strong experience building feature-rich, easy-to-use front-end user experiences for high volume web applications.
- Experience writing backend services in Python (or similar languages)
- Familiarity with building full stack applications or working closely across frontend/backend boundaries
- Strong testing, debugging, and documentation practices
- Interest in building tools that empower other developers
Nice to Have
- Experience with ETL systems or integration frameworks
- Background in building internal platforms or developer tooling
- Experience in cloud-native environments (especially AWS)
- Exposure to data syncing, APIs, or workflow automation
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 visit Klaviyo Rewards to find out more about our Total Rewards package.
Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.
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.
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.
