Research Engineer at LangChain

Department: Engineering

Setup: On-site
Location: New York, New York
Type: Full-time
Level: senior
Posted: Aug 14, 2026

Description

LangChain is hiring a Research Engineer to improve the LangSmith Engine agent by building benchmarks, running experiments, exploring fine-tuning and post-training techniques, and turning successful ideas into production improvements. The role requires strong AI/ML research, LLM and agent experience, software engineering, and an understanding of production systems, with work locations in San Francisco and New York City.

Required Skills

LLMs
Benchmarks
Fine-tuning
Software engineering
Reinforcement learning
Model serving

Additional Information

Minimum Education: Master’s or Ph.D. in a relevant scientific field
Required Previous Experiences: 4+ years of experience in ML/AI research or a closely related field
Hands-on experience with LLMs and AI agents
Experience designing benchmarks, evaluations, and experiments for AI/ML systems
Strong software engineering skills
Preferred Qualifications: Ph.D. in Machine Learning, Computer Science, or Physics
Experience with LLM-as-a-judge, automated graders, synthetic data generation, or human evaluation
Experience with reinforcement learning, preference optimization, SFT, RLHF/RLAIF, or other LLM post-training techniques
Experience optimizing LLM agents for cost, latency, or task efficiency in production
Experience with model serving, inference optimization, distributed systems, or GPU infrastructure