Applied Researcher

River AI builds personal AI systems and is hiring an Applied Researcher to help customers train and improve models for their workflows. The role owns the applied research lifecycle, from problem definition and data preparation through experimentation, evaluation, and production support.

Responsibilities:

• Partner directly with customers across industries to understand their workflows, identify high-value modeling problems, and define success criteria
• Develop data preparation and curation pipelines with customer teams, turning domain-specific data and expert feedback into training datasets and representative evaluations
• Design and run training experiments using techniques such as continued pre-training, supervised fine-tuning, reinforcement learning, and parameter-efficient fine-tuning (PEFT), selecting approaches that fit each customer's goals, data, and compute budget
• Build evaluation suites, analyze model failures, and iterate on data and training methods to improve quality, reliability, and performance on real customer tasks
• Work with customer engineers and River's infrastructure team to scale training runs, resolve bottlenecks, and support deployment and ongoing model improvement
• Turn lessons from customer engagements into reusable training recipes, evaluation tools, and improvements to River's platform