Sezzle

55 live roles · fintech

We are seeking an exceptional Principal Infrastructure Engineer to design, build, operate, and scale the platform that powers Sezzle. Your focus will be the hardest infrastructure problems: increasing throughput, reducing latency, removing capacity bottlenecks, strengthening resilience, and making production operations more automated and predictable as the business grows. You will own complex technical initiatives from architecture and prototyping through implementation, production rollout, and ongoing operation. Your impact will come from the systems you build, the problems you solve, and measurable improvements in reliability, performance, and cost efficiency. Our stack runs on AWS, with workloads orchestrated on Kubernetes and data anchored in Aurora RDS (MySQL and Postgres). You should know these technologies deeply and be comfortable moving between cloud architecture, networking, cluster internals, database performance, and application behavior to understand how the entire system scales. You will write code and infrastructure-as-code, debug production systems, and deliver changes that hold up under real traffic and failure conditions.