Senior Security Engineer - Detection Engineering

Fastly helps people stay better connected with the things they love. Fastly’s edge cloud platform enables customers to create great digital experiences quickly, securely, and reliably by processing, serving, and securing our customers’ applications as close to their end-users as possible — at the edge of the Internet. The platform is designed to take advantage of the modern internet, to be programmable, and to support agile software development. Fastly’s customers include many of the world’s most prominent companies, including GitHub, Yelp, Paramount, and JetBlue.

We're building a more trustworthy Internet. Come join us.

Posting Open Date: October 6, 2026

Anticipated Posting Close Date*: December 6, 2026

*Job posting may close early due to the volume of applicants.

 Senior Security Engineer, Detection Engineering

As a Senior Security Engineer on our Detection Engineering team, you will build the detections that catch malicious activity across the Fastly environment and drive the investigations that follow. We are looking for a teammate with a strong security engineering foundation and hands-on experience in security incident response, detection development, and applying AI to security operations. In this role, you will design and build AI agents and automations to support detection and response, develop advanced detections, perform threat hunts, and lead security investigations.

What You'll Do:

• Develop detections and other analytics to identify threats across cloud, container, corporate, and edge environments.

• Lead security investigations, analyzing complex log sources and telemetry to determine root cause.

• Build AI agents and automations that speed up detection development, triage, and incident response.

• Research, evaluate, implement, and maintain a variety of custom and commercial security tools, such as EDR, SOAR, and SIEM.

• Conduct threat hunts to discover unknown malicious activity across our environment.

• Participate in our on-call rotations.

What We're Looking For: 

• Direct experience integrating AI tools, LLMs, and automated agents into security operations workflows to accelerate alert triage, contextualize telemetry, and speed up incident response.

• Experience developing, testing, and tuning detections using a detections-as-code approach, including version control and CI/CD.

• Proven track record of leading complex security incident investigations, with deep expertise in log analysis, real-time containment, and collecting forensic artifacts.

• Strong coding skills in Python or another general-purpose language, with experience building automations for detection and response.

• In-depth knowledge of major public cloud platforms (e.g., AWS or GCP) and Linux environments, including containers (e.g., Kubernetes), along with their native logging and security tooling.

• Solid grasp of attacker tactics and techniques, with experience in threat hunting or threat modeling to guide detection priorities.

We’ll be super impressed if you have experience in any of these:

• Familiarity with content delivery networks (CDN), edge cloud platforms, or Fastly products and services.

• Experience designing and maintaining scalable ETL processes and data pipelines to ingest, transform, and normalize security telemetry for large-scale analysis.

• Experience deploying AI agents in production to detect threats, enrich alerts, and automate response. 

Work Hours:

• This position will require you to be available during core business hours and support an on-call rotation. 

Work Location(s) & Travel Requirements:

The preferred locations for this position are:

• New York, NY

• San Francisco, CA

• Denver, CO

Fastly currently embraces a largely hybrid model for most roles which allows employees flexibility to split their time between the office and home.  

There is a strong preference for Hybr