Senior Research / AI / ML Engineer
San Francisco, in-office 5 days/week
$180K to $220K base + meaningful equity + full benefits
My client is a profitable YC-backed AI research business focused on developing advanced models and post-training systems for complex, high-impact use cases. They work with enterprise customers and are building novel approaches to reasoning, model training and applied research. The team is small, deeply technical and comes from leading research groups and successful startups.
You’ll work across research and production, helping design, train and refine large models while building the internal training stack that powers them. You’ll also partner directly with customers to understand real-world challenges and turn cutting-edge ideas into deployed systems.
What You’ll Do
• Train and fine-tune large models for practical and research applications
• Contribute to new research directions in reasoning and program synthesis
• Build and improve training infrastructure, data pipelines and evaluation workflows
• Work directly with customers on technical challenges and delivery
• Operate as a core member of a small, high-caliber engineering team
What They’re Looking For
• Hands-on model training experience, ideally including distributed training
• Strong engineering ability with Python and PyTorch or JAX or TensorFlow
• Solid understanding of data, infra and evaluation tooling
• Two to five years of industry experience, or exceptional research-driven grads
• Clear communication and comfort in customer-facing work
• Able to operate autonomously with speed, clarity and ownership
• High-energy and impact-driven mindset
