Hiring: Member of Technical Staff - Research & Post-training Company: Preference Model Location: San Francisco, CA Job Posted Time: 2026-09-12 18:04:43 Employment Type: On-site Target Skills & Keywords : HBase, LLM, Machine Learning, PyTorch, Python, Slack About the job Required Skills: •Models of the future will be able to train themselves on tasks that they are not good at. We are interested in investigating how far we can push the boundaries of self-directed learning. We are looking for •machine learning •Research Engineers or Research Scientists •to push the frontier of post-training on large language models in a role that blends research and engineering, requiring you to implement novel approaches and shape research directions. •What You Will Do: •Train and evaluate models on our proprietary RL environments to validate data quality, surface gaps in task coverage, and close the feedback loop between environment design and model capability. •Architect and optimize our RL training infrastructure, from training abstractions to distributed experiment management, using frameworks like Verl, OpenRLHF, or similar. Help scale our systems to handle increasingly complex research workflows. •Design, implement, and test training environments, evaluations, and methodologies for RL agents. •Profile and optimize training runs end-to-end, from data loading through reward computation, to maximize experiment throughput and shorten the research iteration cycle. •What We are Looking For •Experience running end-to-end LLM post-training pipelines of models sizes at least 7B in size •Proficiency in Python and PyTorch or JAX •Experience with at least one modern RL training framework •Experience building and operating ML infrastructure at scale •You may be a good fit if you also: Compensation: •Competitive cash and equity compensation (>90th percentile) •Ownership and autonomy in a fast moving startup environment •Opportunity to work with top machine learning engineers •Health, vision, dental, benefits •401K match •Lunch provided everyday onsite •Weekly snack orders •Visa sponsorship & relocation support available •We value diverse perspectives and experiences. If you're excited about this role but don't check every box, we still encourage you to apply. •Compensation Interested candidates, please apply directly through the job posting on company's career page or try via AI auto apply on this platform. Don't miss this opportunity to join a forward-thinking team!