Startups · AI

Senior Research Engineer, LLM Training & Post-Training

Lightning AI · New York, New York, United States; Remote; San Francisco, California, United States; Seattle, Washington, United States · Remote

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About Lightning AI

From the PyTorch Lightning creators. Own your AI, don. Backed by Index.

About the role

We're are looking for an experienced Senior Research Engineer who has built, trained, and optimized modern transformer-based language models to join our Research Engineering function at Lightning.

What they're looking for

  • Significant experience training, fine-tuning, evaluating, and/or optimizing transformer-based language models using PyTorch
  • Experience with modern LLM training and post-training techniques such as continued pretraining, SFT, RLHF, preference optimization (DPO, PPO, GRPO), reward modeling, or similar approaches
  • Strong understanding of distributed training and multi-node systems, with experience improving training performance, scalability, and/or efficiency
  • Strong software engineering fundamentals, including building production-quality Python software and research tooling
  • Experience designing experiments, evaluating model performance, and debugging complex training and/or optimization issues
  • Excellent communication and collaboration skills, including the ability to work effectively across research, product, infrastructure, and customer-facing engagements
More about this role

Lightning AI is the company behind PyTorch Lightning. Founded in 2019, we build an end-to-end platform for developing, training, and deploying AI systems—designed to take ideas from research to production with less friction.

Through our merger with Voltage Park, a neocloud and AI Factory, Lightning AI combines developer-first software with cost-efficient, large-scale compute. Teams get the tools they need for experimentation, training, and production inference, with security, observability, and control built in.

We serve solo researchers, startups, and large enterprises. Lightning AI operates globally with offices in New York City, San Francisco, Seattle, and London, and is backed by Coatue, Index Ventures, Bain Capital Ventures, and Firstminute.

The people who thrive here are builders who move fast, communicate openly, take ownership, and continuously improve themselves, their teams, and our company. Here's what that looks like in practice:

  • Move with Urgency: We move quickly, make thoughtful decisions, and keep momentum. We value action over perfection and learn by shipping.
  • Take Ownership: We own outcomes, not just our individual work. We make decisions that move the company...

Read the full posting on Lightning AI's site ↗

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