Senior Security Engineer, Detection & Response

Sezzle

1d•Remote

About The Position

We are seeking a hands-on, high-impact Senior Security Engineer, Detection & Response, to strengthen security operations at Sezzle: detection, incident response, and vulnerability management across our cloud infrastructure and applications. You will join the team that runs our SIEM and detection capability — from log ingestion and audit coverage to detection rules, alert tuning, and investigation workflows — so that access to sensitive systems is attributable and suspicious activity is caught and attributed by our own detections. You will operate the vulnerability-management loop end-to-end, and when incidents happen, you will lead the investigation and see the long-term fix through. 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. You will report to the Director of Information Security and work alongside the engineers who own the security platform and network and zero trust — your detection and response work is what proves their controls hold. This role is ideal for someone who thrives in a fast-paced environment and wants to work on real-world security problems at scale. At Sezzle, AI-assisted engineering is a standard part of how we work. In this role you will use and build agentic workflows for alert triage, investigation, and threat hunting that multiply what the team can cover.

Requirements

6+ years of experience in security, software, or infrastructure engineering, with hands-on experience securing cloud-based production systems and working with real-world security challenges
Experience working with SIEM platforms (e.g., Wazuh, Splunk, ELK) for detection engineering, monitoring, and incident response
Experience designing and tuning detection rules, reducing alert noise, and improving investigation workflows
Strong hands-on experience in vulnerability management — scanning, triage and validation of scanner and bug-bounty findings, remediation coordination, and verification
Strong knowledge of AWS, Linux, and Kubernetes infrastructure, including security architecture and operational best practices
Ability to investigate issues directly using logs, cloud tooling, and system-level data
Experience assessing the detection and logging implications of new systems in design reviews
Knowledge of common security vulnerabilities and mitigation strategies (OWASP, SANS, etc.)
Working knowledge of compliance frameworks such as PCI DSS and SOC 2, particularly logging, monitoring, and evidence expectations
Demonstrated AI-forward engineering: you actively use AI tooling (e.g., Claude Code, Codex, Cursor, or custom LLM integrations) in your work today, and have opinions grounded in practice about where it helps and where it doesn't

Nice To Haves

You have built AI-assisted workflows that others adopted — triage, enrichment, or hunting
Familiarity with log-based detection, telemetry pipelines, and security analytics use cases
Experience with internal penetration testing or adversarial exercises, and translating results into detection and remediation work
Strong understanding of cloud-native security controls, including IAM, network segmentation, and container security
Experience with container and dependency security tools (e.g., Snyk, Trivy, Grype) as an operator of their findings
Experience aligning technical security work with regulatory and compliance expectations
Experience in fintech, payments, or other regulated environments

Responsibilities

Build, operate, and mature SIEM/XDR capabilities, including log ingestion, detection rule development, alert tuning, and investigation workflows
Design and implement detection strategies for suspicious activity, including data exfiltration patterns using application and database telemetry
Extend audit and attribution coverage across the estate — Kubernetes audit logs, database audit logging, SSO and access-path telemetry — so access to sensitive data is attributable to a person or workload, with retention aligned to compliance requirements
Investigate and respond to security incidents across cloud infrastructure and applications, performing root cause analysis and driving long-term fixes
Run proactive threat hunts across cloud and identity planes, building agentic hunting workflows that make hunts repeatable
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
Triage and validate external security findings (including bug bounty reports), distinguishing true positives and coordinating remediation
Contribute to threat modeling and security design reviews for the detection, logging, and incident-response implications of new systems
Apply strong AWS and Kubernetes judgment to secure the systems you operate and advise owning teams on remediation
Support and implement security controls aligned with PCI DSS, SOC 2, and other compliance requirements — with your logging and detection work producing the audit evidence as a by-product
Develop and implement automation (including AI) to improve efficiency in security operations, detection, and response
Participate in the on-call rotation for detection and response and the services you own