Machine Learning Scientist - Open Source Lead

LMArena is looking for a Machine Learning Scientist to lead our open-source research, including open data set and code releases, advancing how the world evaluates and understands AI models in the open. You’ll design, run, and share new methods and experiments that reveal what makes models useful, trustworthy, and capable, grounded in human preference signals and released openly for the full ecosystem and research community to build upon.

Requirements

• Hands-on experience training large-scale models, including reward models, preference models, and fine-tuning LLMs with methods like RLHF, DPO, and contrastive learning.
• Strong foundation in ML and statistics, with a track record of designing novel training objectives, evaluation schemes, or statistical frameworks to improve model reliability and alignment.
• Fluent in the full experimental stack, from dataset design and large-batch training to rigorous evaluation and ablation, with an eye for what scales to production.
• Deeply collaborative mindset, working closely with engineers to productionize research insights and iterating with product teams to align research with user needs.
• Comfortable being a visible representative of LMArena, engaging openly with the research community, and building a strong personal brand to help shape AI research culture.

Benefits

• Competitive salary
• Meaningful equity
• Comprehensive healthcare coverage (medical, dental, vision)
• The opportunity to work on cutting-edge AI with a small, mission-driven team
• A culture that values transparency, trust, and community impact