Senior Security Infrastructure Engineer

About this job

Sezzle is on a mission to financially empower the next generation through innovative, interest-free installment plans that redefine the shopping experience. As a Senior Security Infrastructure Engineer at Sezzle, you will play a hands-on role in strengthening the company's security posture across cloud infrastructure, applications, and developer workflows. You will enjoy a high degree of ownership and autonomy as you tackle real-world security challenges at scale. A normal day in this role combines hands-on security operations with exploratory and design work. You will spend significant time investigating logs, analyzing systems, validating findings, and responding to incidents. Additionally, you will research, evaluate, and build new security capabilities—such as detection systems, supply chain risk controls, and data protection—while partnering closely with engineering teams to embed practical security into how systems are built and operated.

Responsibilities

• Lead and operate vulnerability management across infrastructure, platforms, and applications.
• Build, operate, and mature SIEM/XDR capabilities including log ingestion and detection rule development.
• Investigate and respond to security incidents across cloud infrastructure and applications.
• Design and implement detection strategies for suspicious activity and data exfiltration patterns.
• Lead threat modeling exercises and security design reviews to identify risks early.
• Drive infrastructure and CI/CD hardening initiatives to reduce software supply chain risk.
• Partner with engineering teams to remediate vulnerabilities and improve deployment practices.
• Develop and implement automation to improve efficiency in security operations.

Requirements

• 6+ years of experience in security, software, or infrastructure engineering.
• Hands-on experience securing cloud-based production systems and handling real-world security challenges.
• Strong practical experience in vulnerability management, scanning, triage, and validation.
• Experience working with SIEM platforms like Wazuh, Splunk, or ELK.
• Strong knowledge of AWS, Linux, and Kubernetes infrastructure and security architecture.
• Experience with container and dependency security tools like Snyk, Trivy, or Grype.
• Working knowledge of compliance frameworks such as PCI DSS and SOC 2.
• Demonstrated experience working with Claude or equivalent large language model tools.

Good to have

• Experience designing and tuning detection rules and reducing alert noise.
• Strong understanding of cloud-native security controls including IAM and network segmentation.
• Familiarity with log-based detection, telemetry pipelines, and security analytics.
• Experience designing secure CI/CD workflows to reduce exposure to vulnerable dependencies.
• Ability to align technical security work with regulatory and compliance expectations.

Who should apply

This role suits an autonomous 'DOer' with deep technical expertise who thrives in a fast-paced environment and enjoys hands-on problem-solving across cloud security. Candidates should bring significant experience in security, software, or infrastructure engineering, along with a strong background in AWS, Kubernetes, and vulnerability management. Because this posting explicitly requires 6+ years of experience, it is not suitable for freshers. If you are passionate about building resilient systems, leveraging modern AI tooling, and driving impactful security improvements at Sezzle, you should apply.

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