Senior Security Infrastructure Engineer

About the role

We are seeking a hands-on, high-impact Senior Security Infrastructure Engineer to help strengthen Sezzle's security posture across cloud infrastructure, applications, and developer workflows. This role is ideal for someone who thrives in a fast-paced environment and wants to work on real-world security problems at scale. As a Senior Security Infrastructure Engineer, you will have a high degree of ownership and autonomy to identify risks, investigate issues, and drive meaningful security improvements across our systems. You will work across vulnerability management, detection engineering, supply chain security, and incident response - partnering closely with engineering teams to ensure security is practical, effective, and embedded into how we build and operate systems. You should consider yourself a DOer - someone who is comfortable diving into logs, analyzing systems, validating findings, and working end-to-end to get issues resolved. We value engineers who bring strong technical depth, good judgment, and the ability to turn security insights into actionable outcomes. This role offers the opportunity to shape and scale security capabilities, including detection systems, supply chain risk controls, and security automation. With the support of modern tooling (including AI where appropriate), you will play a key role in improving efficiency, visibility, and resilience across the organization. This role combines hands-on security operations with exploratory and design work. You will spend significant time investigating and resolving real-world issues, while also researching, evaluating, and building new security capabilities across areas like detection, supply chain security, and data protection.

Responsibilities

• Lead and operate vulnerability management across infrastructure, platforms, and applications - including internal scans, dependency analysis, and external findings, validating true positives and driving remediation with engineering teams
• Build, operate, and mature SIEM/XDR capabilities, including log ingestion, detection rule development, alert tuning, and investigation workflows
• Investigate and respond to security incidents across cloud infrastructure and applications, performing root cause analysis and driving long-term fixes
• Design and implement detection strategies for suspicious activity, including data exfiltration patterns using application and database telemetry
• Lead and contribute to threat modeling exercises and security design reviews to identify risks early and strengthen architecture
• Apply deep expertise in AWS and Kubernetes to design, secure, and improve resilient and secure cloud infrastructure at scale
• Drive infrastructure and CI/CD hardening initiatives, with a focus on reducing software and container supply chain risk
• Lead efforts to implement and improve dependency and container supply chain risk detection systems and controls
• Partner closely with engineering teams to remediate vulnerabilities and improve secure development and deployment practices
• Support and implement security controls aligned with PCI DSS, SOC 2, and other compliance requirements
• Develop and implement automation (including AI where appropriate) to improve efficiency in security operations, detection, and response
• Triage and validate external security findings, distinguishing true positives and coordinating remediation
• Demonstrated experience working with Claude or equivalent large language model tools is required; candidates must be comfortable leveraging AI to enhance productivity, research, and communication.
• What We Look For:
• 6+ years of experience in sec

Additional Information

The salary range for this role is $5,000 - $9,500 per month (Gross in USD) About Sezzle: With a mission to financially empower the next generation, Sezzle is revolutionizing the shopping experience beyond payments, blending cutting-edge tech with seamless, interest-free installment plans that make shopping smarter and more accessible. We're not just transforming payments; we're redefining how people discover, interact with, and purchase the things they love while driving real impact on merchant sales through increased conversions and higher order values. As we continue to shape the future of fintech and retail, we're building an innovative, dynamic team passionate about creating more than just a transaction but a truly unique shopping journey. If you're excited about pushing boundaries in tech and delivering a game-changing experience for consumers and merchants alike, come join us at Sezzle and help create the future of shopping!

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