# Senior Machine Learning Engineer, Model Training and Reinforcement Learning at Nebius

- Company: Nebius
- What the company does: Build and scale faster on the purpose-built AI cloud, engineered from silicon to API. Backed by Accel.
- Company website: https://nebius.com/
- Type: Startups (AI role)
- Level: Senior
- Location: Palo Alto, California, United States
- Work setup: On-site
- Posted: 2026-07-22
- Apply by: 2026-10-12
- Apply: https://careers.nebius.com/?gh_jid=4926274101
- Page: https://www.1752.vc/careers/jobs/nebius-senior-machine-learning-engineer-model-training-and-reinforcement-learnin/

## About the role

Nebius Token Factory is building an AI training and model post-training capability for frontier model improvement. This role owns the infrastructure that makes large-scale training and RL experiments possible, reliable, reproducible, and efficient. The work sits at the intersection of distributed systems, GPU performance, model training frameworks, RL pipelines, and production engineering.

## What they're looking for

- Strong Python and PyTorch engineering skills, with the ability to move quickly from idea to experiment to working system
- Hands-on experience across at least two of: model training, post-training/ RL , applied modeling, data pipelines, or large-scale ML systems
- Ability to design rigorous experiments with baselines, ablations, metrics, and failure analysis
- Practical understanding of modern LLM behavior, instruction tuning, preference optimization, and evaluation challenges
- Practical understanding of transformer training bottlenecks, memory pressure, communication overhead, and checkpointing
- Ability to reason quantitatively about model quality, throughput, utilization, reliability, cost, and research velocity

Tags: ML