Software Engineer II - API

Overview

At Klaviyo, we value the unique backgrounds, experiences and perspectives each 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  to see how we empower creators to own their own destiny.

Klaviyo is growing fast, and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at (Use the "Apply for this Job" box below)..

We love tackling tough engineering problems and look for engineers who specialize in certain areas but are passionate about building, owning, and scaling features end to end — breaking through any obstacle or technical challenge 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.

This position is based in our Boston office
, and team members are expected to be onsite at least three days per week
.

Klaviyo operates a real-time data platform coded in Python, built for massive scale on Amazon Web Services (AWS). Engineers come to Klaviyo with experience in a variety of languages and from a number of disciplines.

The API team empowers product development teams at Klaviyo to create consistent, reliable, and developer-friendly public and internal APIs by providing robust frameworks, intuitive tools, and expert support.

• Public API Framework: Building consistent, reliable, and performant public APIs.
• Internal API Platform: A standardized platform for building, deploying, and consuming internal APIs to accelerate development and improve reliability.
• Encoded Objects: Standardized data schema definition and serialization framework ensuring consistency and compatibility across systems.
• API Rate Limiter: System enforcing request limits to protect API reliability and performance.

• Contribute to the evolution of Klaviyo’s public and internal API platforms.
• Participate in code reviews, product specifications, and scope definition.
• Collaborate with product owners and engineering peers to deliver high-quality, scalable solutions.
• Influence the direction and priorities of the API team.

• 3–5+ years of experience in software engineering.
• Experience working with both monolithic and microservices architectures.
• Experience with CI/CD pipelines.
• Strong debugging and performance optimization skills.

Python, Django REST Framework, Django, FastAPI
MySQL / Postgre

SQL, Document

DB, Click House
Redis, Memcached, Rabbit

MQ / Celery / Apache Pulsar

• Experience with metaprogramming.
• Experience with Go.
• Familiarity with JSON:
  
  API.
• Experience designing and building internal or public APIs.
• Experience with Service-Oriented Architecture (preferably in Python).
• Experience working with RESTful applications, APIs, or gRPC.

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.

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: $120,000 — $180,000 USD

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…