Forward Deployed Engineer Lead LLM Post-training
Reflection is an AI research lab building open frontier models and a full AI stack for developers, enterprises, and public-sector users.
Funding history
About Reflection
Reflection develops open-weight AI models, open-source software for customizing and running agents, AI-factory infrastructure, and related solutions. Its current research emphasizes large language models, reinforcement learning, and agentic reasoning.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
You will lead customer post-training engagements from data assessment through training and deployment. You will build reinforcement-learning environments, synthetic-data and evaluation pipelines, prepare datasets, run training loops, optimize distributed training, deploy models, and establish technical standards.
Requirements
- LLM post-training experience at scale
- Reinforcement learning training environments
- Preference optimization workflows
- Synthetic data generation
- Reward models
- Verifiers
- Evaluation methodology
- Multi-node GPU clusters
- Distributed training
- Data pipelines
- Version control for datasets and models
- Reproducible workflows
- 6+ years of engineering experience
- 2+ years focused on LLM post-training in a leadership capacity
- Customer-facing technical experience or interest
Responsibilities
- Lead customer post-training engagements and define training strategies
- Design reward signals, verifiers, datasets, training loops, and customer benchmarks
- Build reinforcement-learning training environments
- Build synthetic data generation, reward model, and preference data workflows
- Build evaluation infrastructure and test sets
- Own data pipelines from raw customer data to training-ready datasets
- Deploy post-trained models across hybrid environments
- Define playbooks and technical standards
- Mentor engineers
Benefits
- Stock options
- Medical, dental, vision, and life insurance
- Annual wellness allowance
- Daily office lunch and dinner
- 22 weeks of paid parental leave
- Unlimited paid time off in the U.S.
- 30 vacation days in the U.K.
- Visa sponsorship support
- Regular off-sites, happy hours, and team celebrations
