Senior Detection Engineer

Fluidstack•Austin, TX

10d•$147,000 - $224,000

About The Position

Fluidstack is building civilization-scale infrastructure for AI, aiming to deliver 10 to 100s of GWs of compute faster than anyone else. The Security & Corp IT Team protects the infrastructure behind this buildout, from corporate endpoints to environments running frontier AI workloads. This role is crucial in building and maintaining the detection and response capabilities across diverse environments, securing critical systems, and ensuring the reliability of security tooling for a rapidly growing company. The team is focused on key problems such as building comprehensive detection and response coverage, securing systems vital for AI labs, implementing security tooling and identity management for a growing workforce, and translating incident learnings into durable detection logic. The company operates with a philosophy of autonomy, urgency, first-principles reasoning, and a passion for advancing AI while ensuring it aligns with human values.

Requirements

5+ years in detection engineering or threat hunting inside a mature security operations org (cloud-native infrastructure, SaaS, or fintech).
Deep hands-on experience with SIEM and EDR tooling: Splunk, Elastic, CrowdStrike, or equivalent, including query languages and pipeline tuning.
Experience writing and maintaining detection logic mapped to MITRE ATT&CK against real adversary behavior.
Strong scripting and automation skills (Python, SQL, or similar) and a detection-as-code workflow (tests, review, and rollback included).
Ability to differentiate between a noisy rule and a broken one, and tune or kill detections before responders learn to ignore them.
Ability to operate with minimal process: scope own work, ship without a mature SOC, and build necessary processes.
Clear writing skills for runbooks and incident reports.

Nice To Haves

Experience securing physical infrastructure or OT/data center environments.
Purple team experience.
Contributions to open-source detection content (Sigma, detection rule repos).

Responsibilities

Own the detection engineering program end to end: threat modeling, detection design, deployment, tuning, and retirement, with coverage mapped to MITRE ATT&CK and gaps documented.
Build detection-as-code pipelines so every rule is version-controlled, tested, and peer-reviewed before it ships, and false-positive rates are measured.
Run threat hunts against real adversary behavior in our cloud, SaaS, and data center environments, and convert findings into repeatable detections.
Drive SIEM and EDR pipeline health: log source onboarding, normalization, and alert quality.
Lead triage and response for the alerts you build, and close out incidents with root-cause writeups that change the detection stack.
Build automation that removes manual triage steps, so the team's alert load scales slower than the company does.