Sr. Software Engineer, Messaging Infrastructure

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 see how we empower creators to own their own destiny.

About Klaviyo

Klaviyo is a leading marketing automation platform that helps businesses grow by delivering personalized experiences. Our mission is to empower creators to own their destiny. We believe in providing an exceptional developer experience that enables our engineering teams to build and ship high-quality software efficiently and with confidence.

About the Team

The Messaging Infra organization at Klaviyo is focused on high-growth customer engagement through various messaging channels (email SMS/MMS/RCS mobile push WhatsApp and more). We work with multiple stakeholders to provide best-in-class service and reliability to connect a wide range of businesses from entrepreneurs to enterprises with their end users. The messaging platform is a mission-critical system responsible for delivering billions of messages and must be architected for massive scale and reliability.

How You Will Make a Difference

• In this role you will own and build features/services that hundreds of thousands of Klaviyo customers rely on daily to drive their business forward.
• Work on crafting our highly-scalable highly-available campaign pipeline that processes and delivers hundreds of millions of messages daily growing to billions scale.
• Collaborate radically with teams and stakeholders across Klaviyo on designs implementations and engineering practices.
• Learn new technologies bring them to the team and apply them to evolve our systems to the next level.
• Help us improve our experimentation and development processes and mentor other engineers on the team.
• Participate in the technical interview process to help maintain a high bar for our growing teams
• Contribute to the company as a subject matter expert constantly pushing yourself to be a better engineer and to level up all of your peers within your team and within Klaviyo.

Who You Are

• 5 years of professional software engineering experience building and operating production distributed systems.
• Deep fluency in at least one backend language (Python Go Java Scala or similar) and comfort navigating large complex codebases.
• Experience on large-scale system architecture technologies and patterns. Have a good understanding of their pros/cons and use scenarios able to apply them to system design by making appropriate tradeoffs to meet the business needs best.
• Love digging into performance and scalability issues to drive breakthrough solutions-- whether its a performance degradation or too many clicks in a workflow a database query timing out or a queue that just wont drain. You recognize all problems can be solved.
• Passionate about growing and improving a product daily using a data driven mindset familiar with system monitoring and alerting techniques.
• Proven experience with being a coach and a mentor for team members and helping them grow.
• Solid understanding of distributed systems fundamentals: consistency models CAP tradeoffs idempotency retries and backoff rate limiting and graceful degradation.
• Ability to operate effectively in a high-ownership culture: you drive your work forwardunblock yourself and hold yourself accountable to outcomes not just effort.

Technologies we use (not exhaustive):

Languages & Frameworks: Python Django React

Data & Infrastructure: MySQL Redis Memcached Apache Zookeeper Apache Pulsar

Cloud & DevOps: AWS (EC2 RDS Aurora) Terraform Jenkins

Location & Work Model:

This role is based in Dublin Ireland and follows a hybrid working model. Klaviyo supports work authorization and relocation for this position.

At Klaviyo we enjoy tackling meaningful engineering challenges and value people who take ownership learn continuously and collaborate openly. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds.

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