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Software Dev Engineer II, Stores Foundational AI -SFAI

Seattle, Washington, United States💼 Full-time💰 $143,700–$194,400🗓 2026-06-29 → 2026-09-26

Core

Design and implement stable, efficient training systems and scalable data infrastructure for large-scale LLM training and reinforcement learning post-training.

Role type

Senior IC machine learning infrastructure engineer (RL post-training)

Builds

End-to-end RL post-training pipelines, training stability systems, and scalable data infrastructure for LLMs

Domain

Generative AI, Large Language Models, Distributed Systems

Deliverable

production ML models

Required skills

Software development, System design and architecture, Machine Learning fundamentals, Transformer architecture, Reinforcement Learning, Data infrastructure design, GPU optimization, Observability system design

Preferred skills

ML frameworks (JAX, PyTorch, vLLM, SGLang, Dynamo, TorchXLA, TensorRT), CUDA/C++/Kernel development, System performance tuning, Parallel computing

Technologies

JAX, PyTorch, vLLM, SGLang, Dynamo, TorchXLA, TensorRT, CUDA, C++, PyTorch, RL algorithms (PPO, GRPO, RLOO)

Responsibilities

Design and build end-to-end RL post-training pipelines at cluster scale, Improve RL training stability by monitoring and tuning key metrics, Optimize RL post-training efficiency (GPU utilization, batching, sequence packing), Partner with research scientists to translate new RL algorithms into scalable systems, Profile and eliminate bottlenecks across compute, networking, and storage, Build observability systems for training dynamics and experiment tracking

Seniority

Senior, hands-on IC

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