Applied Researcher

The role

Applied researchers will work with customers to train and improve models. You will translate real-world problems and customer data into models that deliver value in workflows.

What you will do

• Partner with customers to understand workflows and define success criteria.
• Develop data preparation and curation pipelines.
• Design and run training experiments using techniques like continued pre-training, supervised fine-tuning, reinforcement learning, and PEFT.
• Build evaluation suites and analyze model failures.
• Work with customer engineers and infrastructure teams to scale training runs and support deployment.
• Turn lessons from customer engagements into reusable training recipes and platform improvements.

Required qualifications

• BS, MS, or Ph.D. in Computer Science, Machine Learning, Mathematics, or equivalent practical industry experience.
• Strong understanding of modern deep learning architectures.
• Practical experience training, fine-tuning, and evaluating language or multimodal models.
• Extensive hands-on experience with PyTorch or JAX.
• Track record of writing clean, scalable code for model training and experimentation.
• Ability to turn open-ended problems and imperfect real-world data into working models.
• Strong communication and collaboration skills.
• Ability to work directly with customers and explain technical tradeoffs to technical and non-technical audiences.
• Highly collaborative mindset.
• Ownership of outcomes.
• A bias for action in a fast-paced environment.

Nice to have

• Experience delivering models for customer or industry use cases.
• Expertise in reinforcement learning, preference optimization, synthetic data generation, or adapting models to specialized domains.
• Experience with distributed training, experiment management, or deploying and monitoring models in production.
• Experience partnering with domain experts and working with proprietary or sensitive datasets under customer privacy and security requirements.

Benefits

• Comprehensive health, dental, and vision insurance
• unlimited PTO
• relocation assistance as needed

Before you apply

• We sponsor visas and are committed to supporting the process for the right candidate.

About the company

River's mission is to create personal AI owned and shaped by each individual. They are rewriting the entire stack from personal hardware to frontier deep learning research.