Senior Applied Scientist — Security AI & Graph ML

Amazon.com; Seattle (WA); On-site; USD 167,000 - 226,000; Full time

Job summary

Amazon Leo is seeking an Applied Scientist to be a founding scientist on the Engineering and R&D team within Leo Infrastructure and IP Security. You will build neurosymbolic reasoning platforms and models that detect sophisticated threat actors, and you will define the problems and deploy end-to-end scientific solutions in a production setting.

The role emphasizes research with a production mandate, collaboration with security engineers, and contribution to the platform’s real-time detection and

Qualifications

• 3+ years of building machine learning models for business application experience.
• PhD, or Master’s degree and 6+ years of applied research experience.
• Experience programming in Java, C++, Python or related language.
• Experience with neural deep learning methods and machine learning.
• Experience with graph algorithms, knowledge graphs, unsupervised learning (clustering, dimensionality reduction, anomaly detection), NLP, and embedding-based retrieval.
• Experience designing evaluation frameworks for AI systems where ground truth requires human judgment, including staged rollouts, A/B testing, and expert feedback loops.

Responsibilities

• Design and implement scalable, production-grade neurosymbolic systems that integrate symbolic reasoning over graph-based knowledge representations with LLM agents to deliver reliable, verifiable security outcomes.
• Design and run reinforcement learning and fine-tuning pipelines (GRPO, PPO, DPO) to optimize language models for security reasoning, triage, and detection-authoring tasks.
• Build behavioral and statistical models that detect threat actor behavior, and design the evaluation frameworks that measure model performance against that behavior before trusting a model in production.
• Design and build multi-agent systems that autonomously triage, enrich, and contain security events, including the constrained reasoning, safety guardrails, and validation mechanisms that make automated decisions trustworthy at scale.
• Own the end-to-end science lifecycle, from research and experimentation through production deployment, defining the metrics that measure system performance and real-world security impact.
• Advance the state of the art through publications at top-tier venues, patents, or open-source contributions, and shape the scientific agenda and research culture from day one.

Skills

3+ years ML model building

PhD or Master’s +6 years applied研究

Java, C++, Python

neural deep learning

graph algorithms knowledge graphs NLP

evaluation frameworks for AI systems

Education

PhD

Master’s degree

Tools

R

scikit-learn

Spark MLLib

MxNet

TensorFlow

numpy

scipy

Job description

Amazon Leo is seeking an Applied Scientist to be a founding scientist on the Engineering and R&D team within Leo Infrastructure and IP Security. You will build neurosymbolic reasoning platforms and models that detect sophisticated threat actors, and you will define the problems and deploy end-to-end scientific solutions in a production setting.

The role emphasizes research with a production mandate, collaboration with security engineers, and contribution to the platform’s real-time detection and