Senior ML Engineer - Applied AI & Research Lead

Nebius Group; Brussel; On-site; EUR 120,000 - 190,000; Full time

Benefits offered by this job

Competitive compensation

Career growth and learning

Flexibility and ownership

Collaborative and innovative culture

Opportunity to work on impactful AI

International environment

Job summary

Nebius is seeking senior- and staff-level ML engineers to advance research in AI, focusing on guided search, reinforcement learning for reasoning models, and web-scale data collection. You’ll collaborate across teams to apply findings to production-scale AI systems.

You will work primarily in Python with JAX, training large models across distributed compute, and contribute to publications and technical documentation, in a fast-paced, startup-like environment with a global footprint.

Qualifications

• Deep understanding of ML and reinforcement learning theory.
• Expertise in deep learning for language processing and generation.
• Experience training large models on multi-node systems.
• Strong software engineering skills (Python).
• Experience with RL for LLMs is a plus.

Responsibilities

• Conduct experiments to train large language models on diverse environments.
• Explore guided generation and search in trajectory spaces.
• Mine web-scale data for model post-training and data-efficient learning.
• Run RL configurations in verifiable domains with rigorous analysis.
• Develop and publish results, contributing to technical publications.

Skills

DL & RL

LLMs

Python

JAX

Distributed training

Research leadership

Education

PhD in CS/AI

MS in CS/AI

Tools

JAX

Python

Job description

Nebius is seeking senior- and staff-level ML engineers to advance research in AI, focusing on guided search, reinforcement learning for reasoning models, and web-scale data collection. You’ll collaborate across teams to apply findings to production-scale AI systems.

You will work primarily in Python with JAX, training large models across distributed compute, and contribute to publications and technical documentation, in a fast-paced, startup-like environment with a global footprint.