About the Job
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 cl...
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 to connect a wide range of businesses, from entrepreneurs to enterpri...
As a Lead Software Engineer in the Messaging Infrastructure organization, you'll provide technical leadership to a group of engineers building and scaling the live, event-driven services that power Klaviyo's messaging pipeline end-to-end. You'll drive technical strategy for a system where every message is a real-tim...
Required Skills & Abilities
8+ years of engineering experience building and operating online, real-time distributed systems — systems processing live events where latency and timely processing matter to the customer or downstream service, rather than primarily offline/batch pipelines where processing can be deferred and replayed without immediate customer impact
You've owned production services measured in messages/events per second, not just daily or monthly totals, and can speak concretely to p95/p99 latency under real, unpredictable traffic
You've built with streaming or message-queue platforms (Kafka, Pulsar, RabbitMQ, SQS, or similar) as a core part of a system's design, and can talk through the tradeoffs of the ones you've used
Experienced architecting distributed, event-driven systems at scale — familiar with the tradeoffs involved in keeping a live, high-throughput pipeline reliable, and able to apply them against real business constraints
Proficient in Python and/or Go, and able to pick up the other quickly
Skilled in scaling infrastructure on AWS for systems that must stay available and low-latency under spiky, unpredictable load
Comfortable contributing to architecture and code directly; this is a hands-on role
Strong product and business mindset — you think beyond the code to understand customer impact
Self-directed and delivery-focused — you ship incremental value and iterate
Clear communicator who thrives in a high-autonomy, cross-functional environment
You've already experimented with AI in your work or personal projects and are excited to keep pushing on that
Languages & Frameworks: Python, Django, React
Data & Infrastructure: MySQL, Redis, Memcached, Apache Zookeeper, Apache Pulsar
Cloud & DevOps: AWS (EC2, RDS, Aurora), Terraform, Jenkins
