Software Engineer II Integrations

Team Overview

The Integrations team is responsible for building and maintaining Klaviyos 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 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 Klaviyos 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 youll 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 Klaviyos V3 APIs 3rd party vendors 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 Klaivyos growth into several verticals beyond e-commerce. Youll 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 Klaviyos 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.
• Bachelors 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 its a slow loading UI or too many clicks in a workflow a database query timing out or a queue that just wont 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.
• Youve already experimented with AI in work or personal projects and youre excited to dive in and learn fast. Youre hungry to responsibly explore new AI tools and workflows finding ways to make your work smarter and more efficient.

What Youll do:

• Have an opportunity to make a major impact on the direction and priorities of the Integrations team - wholly owning features that 160000 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 Klaviyos 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 teams 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

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Required Experience:

IC