Lead Software Engineer - API 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 youre a close but not exact match with the description, we hope youll still consider applying. Want to learn more about life at Klaviyo?

Visit to see how we empower creators to own their own destiny.

Why You Should Join the API Team

As a Lead Engineer joining the API team you can expect to be deeply involved in technical discussions across teams, building out public APIs, and growing the team.

You will have input into the teams mission, goals, and roadmap while collaborating along-side technical product owners, product managers, and product analysts.

Together, you'll define scope and specifications while refining RFCs to ensure deliverables are met and stability is maintained.

You'll also be a key player in helping drive the narrative for the technical evolution of the overall public API space as we invest in both our current and future experiences.

The API team is responsible for expanding our API surface to enable Klaviyos customers and partners to build on top of Klaviyo.

Klaviyo already has APIs for storing data and sending communications, primarily for e-commerce applications, but were just getting started! Were looking to expand our API surface to provide external developers the tools they need to solve core use cases.

This role within Klaviyo has resulted from growth and there are ample opportunities to advance given the scope of this position and the teams central role in Klaviyos product.

The API team was recently honored with the prestigious Best API Award at one of the top developer experience conferences in the world Postmans POST / CON 24.

Out of an impressive pool of 100,000 APIs, Klaviyo secured its place in the top 20 companies, joining the ranks of esteemed players such as Microsoft, Meta, and Stripe. Learn more here!

How You Will Make a Difference

• Meet and work with a number of engineers across the company to expand our API surface across Klaviyos various product areas
• Advocate for building Public APIs alongside other interfaces of accessing new features such as UX and mobile. This will require early collaboration with stakeholders from various product areas within the organization during PRD (Product Requirements Document) and RFC (Request For Comments) phases.
• Open up clearly-defined services through our public APIs so that developers can access these objects programmatically.
• Build upon and enhance Klaviyos API framework foundation. This includes features such as framework support for pagination, improvements to versioning, observability, documentation, etc.
• Promote sound API design patterns & standards that result in best in class Developer Experience for customers that use our APIs.
• Ensure that Klaviyo data is exposed to 3rd party callers only through Public APIs.
• Partner with our Go-to-Market team (solution architects, support engineers, developer advocates) to better understand issues developers are facing with our APIs to design and build solutions.
• Be responsible for technical quality, teach others technical expertise and help them develop skills they need to improve within the organization

Tech Stack

• Python, Django, FastAPI, GRPC
• Apache Kafka, Apache Pulsar, RabbitMQ, Spark, Airflow, and other tech from the big data stack
• MySQL, PostgreSQL, Clickhouse, Redis
• Typescript, React, Babel, Jest, Webpack
• AWS, Terraform, Docker, Kubernetes, Pantsbuild, Jenkins, Argo, and other modern DevOps tools

Who You Are

• Extensive experience architecting & building a wide variety of intuitive & consistent public Restful APIs
• Extensive experience consuming 3rd party Public APIs
• Solid understanding of the full stack of technologies that are needed to build and run an API from the ground up
• Passionate about creating systems that elegantly simplify complex patterns and practices
• Experience with Python, Django
• Experience with meta programming (writing programs that manipulate programs). Our API framework and Encoded Objects library (used to define schemas for complex data models) heavily leverage meta programming.
• 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.
• Motivated by having ownership and leading others, excited about taking the initiative to solve tasks in collaboration with others.

Have experience leading projects and groups of engineers.

• Bachelor's degree or equivalent practical experience with 8 years of experience testing, developing, and launching complex software products, and 5 years of hands-on experience in software design and system architecture, with a focus on reliability, fault-tolerance, and high performance.
• Proven experience with being a coach and a mentor for team members and helping them grow
• Proven record of cross team and cross functional collaboration with stakeholders across the company including engineering, product, data science, solution architecture, customer support, GTM.
• Love digging into performance, scalability, and reliability issues to drive breakthrough solutions. You recognize all problems can be solved and are capable of rallying others to address business needs.

Nice to Have

• Experience with AWS
• Experience with DRF(Django Rest Framework) and / or GRPC
• Experience with JSON : API standards
• Experience creating new applications with scalability in mind
• Experience working with both monolithic and microservices architectures
• Track record of working on high visibility projects with requirements you have to actively seek out. Desire to be judged on measurable outcomes and change process to achieve those outcomes
• Experience talking to customers and listening deeply to their wants and needs

The pay range for this role is listed below. Sales roles are also eligible for variable compensation and hourly non-exempt roles are eligible for overtime in accordance with applicable law.

This role is eligible for benefits, including : medical, dental and vision coverage, health savings accounts, flexible spending accounts, 401(k), flexible paid time off and company-paid holidays and a culture of learning that includes a learning allowance and access to a professional coaching service for all employees.

Base Pay Range For US Locations :

$192,000 $288,000 USD

Get to Know Klaviyo

Were 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 were developing to nurture personalized experiences in ecommerce and beyond.

To reach our goals, we need our own crew of remarkable creatorsambitious and collaborative teammates who stay focused on our north star : delighting our customers.

If youre ready to do the best work of your career, where youll be welcomed as your whole self from day one and supported with generous benefits, we hope youll 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.

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