Principal Infrastructure Engineer

This is a fully remote position, open to applicants in Poland.

📋 Description

• Design, construct, manage, and enhance Sezzle's infrastructure platform.

• Take ownership of intricate technical projects from architecture and prototyping to implementation, production rollout, and continuous operation.

• Recognize system limitations and implement enhancements to accommodate increased traffic, data volume, and workload complexity.

• Link business workflows and transaction patterns to infrastructure enhancements across applications, data, and systems.

• Develop capacity models, conduct load and stress testing, identify bottlenecks, and validate improvements in throughput, latency, saturation, and costs.

• Design resilient AWS accounts, IAM, network, and service architectures, including multi-AZ or multi-region solutions.

• Build and manage the Kubernetes platform, encompassing lifecycle automation, workload isolation, resource allocation, autoscaling, upgrades, and deployment reliability.

• Scale and optimize Aurora RDS for MySQL and Postgres, addressing queries, indexes, connections, replication, failover, schema changes, and migrations.

• Define and instrument service-level objectives and error budgets; implement failure isolation, backpressure, load shedding, and safe retry mechanisms.

• Participate in on-call duties and lead technical recovery during critical incidents and outages.

• Implement and evaluate disaster recovery, backups, restores, and failover processes against recovery objectives.

• Develop infrastructure-as-code and operational automation for provisioning, configuration, deployments, upgrades, and recovery.

• Enhance observability through metrics, logs, traces, dashboards, and actionable alerts.

• Ensure safe infrastructure migrations with phased rollouts, validation, compatibility checks, and rollback strategies.

• Improve cloud cost efficiency through resource right-sizing, utilization, autoscaling, storage optimization, and quantified savings.

• Build and assess AI-assisted tools for incident investigation, runbooks, anomaly detection, and toil reduction.

• Draft architecture proposals, evaluate trade-offs through prototypes and benchmarks, review changes to shared infrastructure, and document system operations and failures.

• Report to engineering leadership and collaborate with application engineering, Security, and Compliance teams.

⛳️ Requirements

• Bachelor's degree in Computer Science or a related technical field (required).

• Over 12 years of experience in infrastructure, platform, site reliability, software development, or related engineering fields.

• Extensive production expertise with AWS, covering compute, IAM, multi-account architectures, VPC design, and private connectivity.

• Profound production expertise with Kubernetes, including cluster lifecycle management, scheduling, resource allocation, autoscaling, networking, and troubleshooting.

• In-depth knowledge of RDS/Aurora MySQL and/or Postgres at scale.

• Proven track record of delivering infrastructure scaling improvements personally.

• Strong coding and automation abilities using Golang, Python, or similar programming languages.

• Experience with infrastructure-as-code tools such as Terraform or equivalent.

• Strong foundational knowledge in Linux, networking, DNS, TLS, storage, concurrency, and distributed system failure modes.

• Experience managing a 24/7 high-availability platform with direct customer or revenue impact.

• Hands-on experience in incident response and postmortem remediation.

• Willingness to participate in an on-call rotation.

• Experience in implementing and testing disaster recovery in line with defined recovery objectives.

• Practical experience in observability, load testing, capacity planning, and safe CI/CD practices.

• Active utilization of AI tools in engineering or operations.

• Ability to navigate ambiguous technical challenges through to production delivery while collaborating across various engineering disciplines.

• Preferred qualifications include EKS experience, fintech/payments/banking background, multi-region architectures, chaos engineering expertise, knowledge of Prometheus/Grafana/Loki/Tempo, internal platform capabilities, and AI-assisted operational automation.

🏝️ Benefits

• Competitive gross monthly compensation ranging from $12,500 to $20,800 USD based on location and experience level.

• Open-source-focused technology environment.