Software Dev Engineer II, Stores Foundational AI -SFAI
Key job responsibilities
Key job responsibilities
In this role you will leverage both your engineering and machine learning background to help develop generative AI for shopping. On a day-to-day basis, you will:
- Design and implementation of a stable and efficient training system for model training and reinforcement learning that scale to various of model sizes and architecture.
- Collaborate with other talented applied scientists and engineers to improve training efficiency and reliability that accelerates innovation.
- Design and implement scalable data infrastructure: that handle Amazon-scale data ingestion, processing, and delivery across different training and evaluation stages;
- Quickly learn and adopt state-of-the-art technologies and algorithms in the field of Generative AI.
A day in the life
On any given day, you may work on:
Design and build end-to-end RL post-training pipelines (rollout → reward → optimization) at cluster scale
Improve RL training stability (PPO / GRPO / RLOO) by monitoring and tuning key metrics such as reward, KL divergence, and policy stability
Optimize RL post-training efficiency (GPU utilization, batching, sequence packing, async rollouts)
Partner with research scientists to translate new RL algorithms into scalable, production-ready systems
Profile and eliminate bottlenecks across compute, networking, and storage
Build observability systems for training dynamics, system health, and experiment tracking
Collaborate cross-functionally to run experiments, iterate quickly, and unblock research progress
Contribute to system design and long-term technical roadmap
About the team
The SFAI Training Infrastructure team builds a unified platform for large-scale LLM training, supporting the full lifecycle from pretraining to fine-tuning and RL post-training. We focus on solving hard system challenges at the intersection of distributed systems and machine learning, building a platform that is:
Scalable — Efficiently train modern model architectures across large-scale compute environments
Reliable — Enable long-running jobs through fault tolerance, monitoring, and automated recovery
Efficient — Maximize hardware utilization and throughput through system-level optimizations
Simple and Unified — Provide a consistent, config-driven interface across models and workflows