Software Engineer II - Integrations

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 klaviyo.com/careers to see how we empower creators to own their own destiny.

Team Overview 

The Integrations team is responsible for building and maintaining Klaviyo’s integrations to a variety of 3rd party vendors. These vendors can be grouped across a number of industries such as ecommerce, point of sale, payment processing, advertising, and fundraising. In order to enable our customers to integrate with these different vendors we provide easy-to-use interfaces that guide our customers through the setup and management of an integration. Behind the scenes, we use a variety of pipelines to process data flowing to and from these vendors at scale. We collaborate closely with internal stakeholders and have substantial exposure to Klaviyo's customers, including businesses, partners, and third-party developers.

***Must be able to work onsite in the Boston office at least three days per week***

How you’ll make an impact

The Integrations team operates at the intersection of distributed systems, software architecture data mapping & pipelining, scalability, and reliability. As a Software Engineer, you will help us build thousands of integrations across various verticals in a fast, flexible, efficient, and maintainable way, resulting in world class customer and developer experiences. Critical components of the Integrations space include Klaviyo’s V3 APIs, 3rd party vendor’s APIs, inbound and outbound data pipelines, and data mapping and transformation. You will have an opportunity to learn our existing end-to-end integration workflow and help scale it up to support the next evolution of Klaivyo’s growth into several verticals beyond e-commerce. You’ll work closely with a team of talented software engineers, data scientists, product managers, and UX/UI designers who are eager to make the process of integrating with Klaviyo fast, efficient, and seamless. Your skills as a software engineer, outside-the-box thinking, and execution will help shape Klaviyo’s trajectory for the next decade.

Who you are

• You are passionate about building software effectively and for the long-term. 
• You have 4+ years of hands-on software development experience creating and maintaining highly available, full-stack SaaS products at scale.
• Bachelor’s degree or equivalent.
• A good understanding of the Integrations technical space - 3rd party APIs, authentication, storage, and data pipelines.
• You have an in-depth understanding of commonly used web architecture design patterns when it comes to highly scalable systems. 
• You have been a successful interface between the team and the rest of your product area. You have been responsible for owning and delivering projects or features of projects including design, development, and deployment.
• You possess excellent verbal and written communication skills. Through effective proactive communication and planning, you keep your team up to date on project progress and any blockers or delays.
• You like to question convention, proactively find ways to innovate, and are intrinsically motivated to drive incremental improvements that deliver value to the business.
• You like working on small, autonomous agile teams. Enjoy shipping code early and often in an agile fashion, pairing with product management, business stakeholders, and other engineers to craft better software.
• You have a good understanding of popular AI tools (ChatGPT, Claude Code, Cursor, Gemini, etc.) and know how to use them effectively in your own day-to-day workflow to increase coding and productivity efficiency.
• You enjoy working with new technologies ranging from the frontend to backend, and are particularly passionate and an expert in various tech stacks.
• Ability to dig into performance and scalability issues to drive breakthrough solutions-- whether it's a slow loading UI or too many clicks in a workflow, a database query timing out, or a queue that just won’t drain.
• You like creating, teaching, and improving shared engineering processes. 
• You are successfully able to estimate and manage project timelines and risks to ensure the team will be in a position to deliver on its commitments.
• You are proficient in writing technical specifications and documents based on product feature specifications provided by the Product team, and are adept at breaking down and articulating complex technical concepts in a clear and concise manner.
• You are capable of leading discussions and presentations to ensure alignment on architectural decisions, promoting transparency, and facilitating a shared understanding across teams. 
• Highly collaborative, ambitious, and ability to champion ideas based on merit. At the same time, being humble enough to recognize your own areas of improvements and open to feedback and continuous learning.
• You’ve already experimented with AI in work or personal projects, and you’re excited to dive in and learn fast. You’re hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient.

What You’ll do:

• Have an opportunity to make a major impact on the direction and priorities of the Integrations team - wholly owning features that 160,000+ customers rely on daily to reach 4B+ consumers to drive their business forward.
• Be responsible for the mission, technical direction and operations of projects that have immediate impact.
• Responsible for building and managing Klaviyo’s integrations, integration settings pages, API services that communicate with 3rd-party vendor APIs, data transformation of data flowing between Klaviyo and the 3rd-party vendors, as well as wiring up the API Services into a number of data pipelines.
• Helping architect and design robust and high performance data processing and storage systems to serve different internal and external use cases.
• Build prototypes, establishes design patterns, consults with domain experts and otherwise wors to ensure a team's successful delivery of technical solutions.
• Contribute to the Klaviyo R&D team as a subject matter expert in multiple areas.
• Provide quality PR reviews for our code-owned areas of the application.
• Lead by example and help improve engineering processes and workflows within the Integrations space as well in the wider engineering community.

Tech Stack:

Klaviyo operates a real-time data analytics platform coded primarily in Python that is built for massive scale and hosted on Amazon Web Services (AWS). New hires come to Klaviyo  from a number of disciplines with experience in a variety of languages and tech stacks. Here is our primary tech stack:

• Python / Django 
• Typescript / React
• MySQL / Redis / Memcached
• RabbitMQ / Celery / Apache Kafka / Apache Pulsar
• Kubernetes
• AWS

At Klaviyo, we love tackling tough engineering problems and look for employees who are passionate about building, owning, and scaling features end-to-end and breaking through obstacles or technical challenges in their way. We push each other to move out of our comfort zone, learn new technologies, and work hard to ensure each day is better than the last. 

Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at https://klaviyo.tech

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.

IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls.

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