# Senior Research Engineer, LLM Training & Post-Training at Lightning AI

- Company: Lightning AI
- What the company does: From the PyTorch Lightning creators. Own your AI, don. Backed by Index.
- Company website: https://lightning.ai/
- Type: Startups (AI role)
- Level: Senior
- Location: New York, New York, United States; Remote; San Francisco, California, United States; Seattle, Washington, United States
- Work setup: Remote
- Posted: 2026-08-12
- Apply by: 2026-10-08
- Apply: https://job-boards.greenhouse.io/lightningai/jobs/7860628003
- Page: https://www.1752.vc/careers/jobs/lightning-ai-senior-research-engineer-llm-training-and-post-training/

## 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

Tags: Research