Senior Security Engineer, Detection and Response

As Marqeta's Senior Security Engineer on the Security Operations and Response team, you will lead incident response for North America and shape how we detect and respond to threats using AI-driven automation in a Next-Gen Agentic SOAR. You'll join a Security Operations & Response team that builds its own AI tools to speed up investigations and strengthen Marqeta's security posture. In this role, you'll serve as the lead technical responder during security events, engineer automated detections and response workflows, run advanced threat hunts, help to build a resilient and comprehensive security operations program, and mentor junior teammates on incident response best practices, while participating in a 24x7 on-call rotation.

We work Flexible First  This role can be performed remotely anywhere within the province where you reside, whether that’s Ontario, Canada or British Columbia, Canada. We’d love for you to join us!

This position is for an existing vacancy.

• Serve as the lead security responder in North American timezones, triaging and investigating complex alerts and acting as a core member of the Cybersecurity Incident Response Team
• Participate in 24x7x365 on-call rotations, providing senior-level expertise and escalation support for security events and incidents
• Engineer, maintain, and continuously optimize detection logic across multiple data sources, using threat modeling to keep coverage current with the evolving attack landscape
• Design detection coverage mapping that documents capabilities and identifies blind spots in the threat landscape
• Develop and track KPIs with leadership, including detection effectiveness, false positive rates, and mean time to detect, respond, and recover
• Create and maintain incident response runbooks, SOPs, and technical documentation to ensure consistent response operations
• Mentor junior team members in security operations best practices, detection engineering, and incident response methodologies
• Build automation workflows and orchestration playbooks that improve detection engineering, threat hunting, and incident response
• Develop and use AI-driven tools for Security Operations and Incident Response
• Conduct proactive, hypothesis-driven threat hunts across corporate and production environments, and support the logging and monitoring infrastructure that enables them

• 5+ years of hands-on experience in security operations with emphasis on Incident Response and Detection Engineering. Additional expertise in threat hunting, cyber threat intelligence, and digital forensics is preferred.
• Industry certifications in Incident Response or related fields are strongly preferred, such as GCIH, GCFA, GIME, OSIR, or GEIR.
• Intellectual curiosity with a passion for understanding emerging threats, analyzing attack patterns, and continuously learning about evolving security landscapes and adversary tactics.
• Strong investigative instincts that compel you to dig deeper into anomalies, follow evidence trails, and reconstruct complex security incidents from fragmented data.
• Commitment to proactive learning and staying ahead of evolving threats by researching emerging attack techniques and sharing insights with the security team.
• Solid technical foundation in security concepts and technologies, with hands-on experience using enterprise security tools including EDR, NDR, CSPM, EASM, SIEM, SOAR, and Cloud Security platforms such as Guard Duty.
• Proficiency with threat intelligence frameworks such as MITRE ATT&CK and their application in assessing detection capabilities and coverage gaps.
• Expertise in developing new threat detection use cases based on security telemetry analysis, environment baselining, actionable threat intelligence, and incident response…