Principal Infrastructure Engineer

About the role

Sezzle is looking for a Principal Infrastructure Engineer to design, build, operate and scale the platform powering its business. The focus is on hard infrastructure problems: increasing throughput, reducing latency, removing capacity bottlenecks, strengthening resilience and making production operations more automated and predictable. The role owns complex technical initiatives from architecture and prototyping through rollout and ongoing operation, and reports to engineering leadership.

Key responsibilities

• Own the architecture and evolution of core infrastructure, prioritise improvements and implement changes as traffic, data and workload complexity grow.
• Build capacity models, run load and stress tests, and diagnose bottlenecks across compute, networking, Kubernetes and databases.
• Design resilient AWS account, IAM, network and service architectures, and build and operate the Kubernetes platform, including autoscaling and safe upgrades.
• Scale and optimise Aurora RDS (MySQL and Postgres), tune queries and indexes, and plan capacity and migrations.
• Define service-level objectives and error budgets, and take part in on-call and incident recovery, including full outages.
• Implement disaster recovery, backup, restore and failover mechanisms, and run recovery exercises.
• Build infrastructure-as-code and operational automation, and improve observability with metrics, logs, traces and alerts.
• Deliver safe migrations, improve cloud cost efficiency, and build and evaluate AI-assisted operational tooling.

Required profile

• Bachelor's degree in Computer Science or a similar technical field.
• 12+ years of experience in infrastructure, platform, site reliability, software development or related fields, with hands-on production infrastructure at scale.
• Deep AWS, Kubernetes and Aurora RDS (MySQL and/or Postgres) expertise; EKS experience strongly preferred.
• Experience with observability, load testing, capacity planning and CI/CD, and hands-on incident response and DR testing.
• Willingness to join an on-call rotation and to recover production systems under pressure.
• Preferred: fintech, payments or banking background, multi-region architecture, chaos engineering, Prometheus/Grafana/Loki/Tempo, and internal platform tooling.

Required skills

• AWS, Kubernetes, Aurora RDS (MySQL, Postgres)
• Golang, Python, Terraform or equivalent infrastructure-as-code
• Linux, networking, DNS, TLS, storage, distributed systems debugging
• Observability, load testing, capacity planning, CI/CD

Compensation is stated as $12,500 - $20,800 USD per month in gross amount, depending on location and experience.