Principal Site Reliability Engineer

📋 Description

• • Sezzle is seeking a highly experienced and motivated Principal Site Reliability Engineer to join our rapidly growing FinTech company. This is a remote role within the United States, offering a significant opportunity for career advancement and the chance to make a substantial impact on our infrastructure and operational excellence. As a Principal SRE, you will be empowered with a high degree of autonomy and authority to proactively identify, diagnose, and resolve complex issues across our infrastructure, deployment pipelines, operational workloads, and overall systems. We are looking for a true "DOer" who can leverage their deep expertise and embrace AI tooling to drive significant scaling and efficiency improvements throughout the organization.
• • You will play a pivotal role in architecting, upgrading, designing, and building robust, scalable infrastructure solutions. This includes leveraging cutting-edge technologies such as Kubernetes and AWS, optimizing our RDS instances (MySQL/Postgres), and implementing modern distributed system patterns. Your contributions will be critical in driving the infrastructure team's roadmap, pushing us towards higher levels of reliability, recoverability, and scalability to support our aggressive business growth.
• • A key responsibility will be to lead capacity planning initiatives, conduct performance benchmarking, and collaborate with the team to rigorously stress-test our systems. You will be instrumental in identifying performance bottlenecks and ensuring our infrastructure is prepared to handle increasing demands and future growth. Furthermore, you will be responsible for defining, maintaining, and enforcing Service Level Agreements (SLAs) and establishing comprehensive alerting strategies across our entire infrastructure.
• • You will lead the charge in developing more sophisticated signal anomaly detection capabilities and implementing more effective, flexible, and actionable alerting mechanisms. This role also presents a unique opportunity to help lead Sezzle's AI enablement efforts. You will identify and champion opportunities to apply AI and automation technologies to enhance infrastructure reliability, boost developer productivity, and improve internal tooling, making Sezzle a leader in AI-driven operations.
• • Building consistency and scalability across our distributed microservices architecture will be a core focus, ensuring that performance and reliability are maintained even as our systems evolve. You will be responsible for establishing and continuously evolving engineering best practices in areas such as observability, security, and CI/CD processes across all relevant teams. Your leadership will extend to mentoring junior engineers, fostering a culture of continuous learning, innovation, and unwavering operational excellence.
• • Collaboration will be key, as you will work cross-functionally with various teams to translate high-level business goals into actionable technical roadmaps and ensure the delivery of impactful results. You will be expected to bring new ideas forward, influence technical decisions, and lead complex, high-stakes technical initiatives from conception to successful implementation. Your ability to deploy significant changes to production environments regularly will be a testament to your hands-on approach and commitment to continuous improvement.
• • We expect you to possess a deep understanding of SQL-based RDBMS, including MySQL and PostgreSQL, with a proven track record of optimizing schema and queries for peak performance at scale. Proficiency in observability tools such as Prometheus, Grafana, Datadog, or New Relic is essential. A solid grasp of distributed systems design patterns, including concepts like transactional outbox, event-driven architecture, stream processing, and message queues, is also critical for success in this role.
• • Your experience should include deploying and managing containerized microservices within Kubernetes environments and a strong understanding of CI/CD pipelines. Familiarity with modern AI developer tooling, such as Claude Code, Gemini CLI, Codex, or Cursor, and a demonstrated ability to use these tools to enhance engineering productivity will be highly valued. Proficiency in Golang, including building and maintaining RESTful APIs, and a history of shipping commercial APIs and data-driven applications in high-growth, fast-paced environments are also key requirements. You will be a leader who guides technical direction, demonstrably improves system reliability, and successfully scales high-traffic services.
• • We are looking for individuals who embody relentlessly high standards, are not bound by convention, thrive on action and calculated risk-taking, earn trust through attentive listening and candid communication, possess backbone with the ability to disagree and commit, and consistently deliver results with exceptional quality and timeliness. Your passion for technology and commitment to excellence will be instrumental in shaping the future of Sezzle's platform.