Staff AI Research Engineer - Post-Training & Evaluation

True; Mountain View (CA); On-site; USD 200,000 - 300,000; Full time

Job summary

We are seeking an engineer to advance post-training and continual learning for production agents in an early-stage AI company. You will build evaluation suites, run experiments, and transform findings into reliable platform components.

Requirements include 1–5 years of hands-on ML/AI engineering, strong Python, and experience with LLM post-training, evaluation, or inference. On-site in Mountain View, CA with visa sponsorship.

Qualifications

• 1–5 years engineering experience in AI startup or ML research.
• Hands-on with LLM post-training, evaluation or inference.
• Solid Python and CS fundamentals.

Responsibilities

• Build evaluation suites, graders, and data pipelines using production workflows and traces.
• Own post-training projects in customer settings, including data work, evaluations, reinforcement learning environments, and training runs.
• Implement agent environments and harnesses for reproducible experiments and training data generation.
• Run and analyze post-training experiments, reproduce promising research, and debug related systems.
• Turn successful experiments into reliable components of a post-training and continual learning platform.

Skills

Python

ML foundations

CS fundamentals

LLM post-training

Experiment debugging

Communication

Tools

PyTorch

JAX

Reinforcement learning

vLLM

Megatron

SGLang

Job description

We are seeking an engineer to advance post-training and continual learning for production agents in an early-stage AI company. You will build evaluation suites, run experiments, and transform findings into reliable platform components.

Requirements include 1–5 years of hands-on ML/AI engineering, strong Python, and experience with LLM post-training, evaluation, or inference. On-site in Mountain View, CA with visa sponsorship.