Research Engineer / Scientist, Reinforcement Learn

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Research Engineer / Scientist, Reinforcement Learn in UK new

Harvey
Full time
Email

UK
10/31/2026
Report

London

Responsibilities

Own and pursue research to improve model capability on long-horizon legal reasoning and agentic workflows.
Design and run post-training experiments using supervised fine-tuning and reinforcement learning on leading open-weight models.
Develop reward functions and verifiers for semi-verifiable tasks, including rubrics, learned preference models, and expert preference data.
Run and debug large-scale training while addressing divergence, reward hacking, and instability.
Build and use rigorous evaluations to track improvements and determine what ships.
Design, implement, test, and debug code across the research stack.

Requirements

Hands-on experience post-training large language models with supervised fine-tuning, reinforcement learning, and preference optimization.
Direct ownership of training runs and results.
Deep machine learning fundamentals and experience getting distributed training runs working reliably.
Strong Python engineering skills, including production-quality code and end-to-end system ownership.
Research experience in reinforcement learning for language models or reward modeling.
Ability to move quickly from experiments to shipped improvements.
Publications are welcome but not required.

Salary: $230k - $340k/yr

Harvey

Harvey is domain-specific AI for legal and professional services. Adopted by Fortune 500 companies like AT&T, Verizon, Cox, Koch, KKR, Bridgewater, more than 100,000 lawyers across 2,400+ customers in 70 countries and over 75% of AmLaw 100 law firms rely on Harvey to advance legal expertise faste...

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