Founding Engineer - ML Research

Willow, a well-funded Series A AI/ML startup, is seeking a Founding ML Research Engineer to build and scale its AI research backbone. The role involves designing, training, and evaluating ML models, including LLMs and diffusion models, and developing scalable experimentation pipelines. This on-site, full-time position in Mountain View, CA offers a competitive salary and equity package.

• Design, train, and evaluate ML models including LLMs, diffusion models, and domain-specific architectures.
• Develop scalable experimentation pipelines for data, model, and evaluation workflows.
• Collaborate closely with data and infrastructure teams to optimize training throughput and model quality.
• Contribute to open research, internal benchmarks, and emerging techniques in multimodal and generative AI.
• Rapidly prototype and productionize research insights into usable tools and models.
• Define foundational technical culture — set standards for research rigor, documentation, and reproducibility.

• 3–10 years of hands-on experience in ML research, applied ML, or ML systems engineering.
• Strong proficiency in Python and ML frameworks: PyTorch, JAX, TensorFlow.
• Deep familiarity with model architectures including Transformers, Diffusion Models, and RLHF techniques.
• Experience designing and building scalable experimentation pipelines for data, model, and evaluation workflows.