Senior Security Engineer - Detection & Response

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny. Klaviyo is looking for a Senior Security Engineer to add to our growing Detection & Response Team. This is an engineering role that spans the full detection and response lifecycle - leveraging software development practices to build detections, triaging alerts, lead investigations, respond to incidents, perform threat hunting, and build the tooling that keeps us from doing the same work twice. As a member of the team, you will have the opportunity to work on complex large-scale security challenges across Klaviyo’s enterprise, cloud, and product environments, and shape how an engineering-first D&R function uses automation and AI in production, at scale, alongside talented and ambitious colleagues spanning multiple regions and timezones. How you will make a difference: Leverage engineering practices to develop, test, and deploy high-fidelity rule-based and anomaly-based detections-as-code Detect and respond to cyber threats using security data lake, SIEM, and cloud platforms Respond to alerts, cyber threats, and drive end-to-end incident response investigations Perform digital forensic investigations to include collection and analysis of evidence Automate and codify detection and response workflows and processes Build security tooling to drive automation across D&R lifecycle Improve and maintain detection and response pipelines and underlying systems Work with our Threat Intelligence team to identify and respond to sophisticated threats Develop AI-first security systems to automate detection and response operations Conduct threat hunts across corporate, cloud and product environments Support data engineering workflows for core security data lake and SIEM platforms Be an active member of D&R on-call rotations Coach and mentor security engineers within the detection & response team We’d love to hear from you if you have: 5+ years of hands-on security experience in modern cloud environments Experience in triaging and responding to cyber threats Experience in large-scale log analysis, incident response and/or digital forensics Experience with centralized security data lakes and SIEM solutions Hands-on experience in writing detections-as-code Solid data querying skills (e.g. SQL, Splunk) Familiarity with large-scale data pipelines and data engineering techniques Proficient in programming languages to automate / build (e.g., Python, Go or similar) Proven experience with git/GitHub and CI/CD automations Familiarity with tactics, techniques, and procedures used by threat actors Experience being part of detection and response or incident response on-call Engineering-first and AI-first approach for all work performed Strong passion for continuous learning and staying updated on evolving technology Strong oral and written communication skills Team player with a strong, self-managing work ethic Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, includ