YUGENOX·JOBS

LLM Data Researcher

Clera · Barcelona

on-sitefull-timeEngineering

About the role

ABOUT THE ROLE

Join the founding research team at an AI company to investigate whether expert-authored datasets improve frontier language models and inform future product direction. The role focuses primarily on hands-on experimentation, with collaboration across clients, partners, and the data team.

WHAT YOU'LL DO

- Post-train models on curated datasets, measure performance changes, and diagnose cases where the data does not improve results.

- Design and run evaluations of frontier language models across expert domains such as law, medicine, and finance.

- Select and apply training approaches, including supervised fine-tuning, reinforcement learning, and preference-based methods.

- Turn research findings into dataset specifications and product recommendations.

- Share results through research papers, public benchmarks, and blog posts.

WHAT WE'RE LOOKING FOR

- A PhD in machine learning or NLP, completed or near completion, or an equivalent research record.

- Hands-on experience with reinforcement learning environments for LLMs or RL-based LLM post-training, supported by research, code, or lab or industry work.

- Experience personally post-training and evaluating LLMs end to end, including SFT, RLHF, RLVR, reward modeling, or preference optimization.

- Experience designing or building robust LLM evaluations or benchmarks.

- Early-career research experience, from a PhD nearing completion to a few years post-PhD.

- Ability to communicate technical findings to research, operations, and non-technical audiences, and fluency with AI tools and coding agents.

- Professional English; publications at leading ML or NLP venues or evaluation tooling experience are a plus.

COMPENSATION & BENEFITS

Competitive salary, equity, and relocation support are available. Salary range and visa sponsorship details were not provided.

LOCATION

Full-time, on-site in Barcelona, Catalonia, Spain. Relocation to Barcelona is expected if you are not already based there.

Text as published by Clera. We don't edit postings; apply and ask questions on the employer's site.

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Posted
Nov 14, 2026 (today)
First seen by us
Nov 14, 2026
Still listed
Nov 14, 2026