The LLM Data Company
Post-training Data Research
Founding Research Engineer
About the role
About The LLM Data Company
The LLM Data Company (YC X25) provides post-training data and RL environments to foundation model labs and frontier applied AI companies. We have raised $3.6m from Tier 1 VCs and are growing 200%+ month-over-month.
Responsibilities
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Design and implement scalable RL recipes for post-training task-specific models
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Develop modular environments, reward functions, and evaluator scaffolds for internal and customer-facing tasks
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Drive research at the intersection of scalable infra and modern RL frameworks to enable RL-as-a-service
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Drive foundational research to publish open source environments and training data
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Build data generation and curation pipelines to support frontier post-training
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Collaborate with product teams to deliver a user friendly interface for non-technical users to generate data
Qualifications
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Bachelor or Master in Computer Science or related field
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Comfort with core tooling (verl, PyTorch, etc.)
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Familiarity with modern post-training techniques (GRPO, etc.)
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Experience with evaluations and reward engineering
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Published in top journals (ICLR, NeurIPS, ICML, etc.)
Why you should join
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Cutting-edge research : Work on unpublished, novel training environments
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Direct lab exposure : Projects that labs actually use and validate in production
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High autonomy : Wide design space to propose and run experiments with minimal oversight
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Early team member : Join as one of the first 10 people with significant equity upside
About The LLM Data Company
The LLM Data Company is a YC X25 company creating post-training data and RL environments for AI labs and applied AI companies. We have raised $3.6m from Tier 1 VCs and are growing 200%+ month-over-month.
