Senior AI Engineer I

As BillionToOne scales rapidly, we are building a world-class Commercial Data & Applied AI team. We are currently seeking a highly motivated Senior AI Engineer I to support the design and implementation of AI and automation solutions that optimize operations across our commercial, billing, and customer experience teams.

This is a full-time senior role for engineers excited about applying LLMs, AI, and automation to real-world business challenges in healthcare. You will have the opportunity to join a new team and help shape the vision and culture. You will collaborate cross-functionally with stakeholders in Sales, Marketing, Revenue Operations, Billing, Customer Experience, and IT to identify high-impact opportunities for AI-driven solutions that improve scalability and efficiency.

We are builders at heart. We value a strong sense of ownership, intellectual curiosity, and a bias toward action.

This is a hybrid role requiring 2-3 days per week on-site in Menlo Park with the team.

Responsibilities:

• Build and deploy LLM-powered applications (retrieval systems, AI agents, workflow automation, vector storage) that integrate with internal systems and data sources
• Partner with business stakeholders to identify automation opportunities, scope requirements, and define success metrics
• Build lightweight data pipelines and analytics to support AI applications and measure their impact
• Own projects end-to-end: from prototyping and iteration through production deployment and monitoring
• Establish best practices for prompt engineering, evaluation, and responsible AI use as the team scales
• Develop and lead internal training sessions on LLM fundamentals, prompt engineering, and AI-assisted development tools

Qualifications:

• 5+ years of experience in software engineering, data science, or ML engineering
• Hands-on experience building applications with LLM APIs (OpenAI, Anthropic, etc.)
• Strong Python proficiency and comfort with SQL and relational databases
• Experience deploying and maintaining production systems
• Familiarity with AWS
• Excellent communication skills and ability to translate business problems into technical solutions
• Self-directed and comfortable with ambiguity in a 0-to-1 environment

Nice-To-Haves:

• Previous entrepreneurial experience
• Experience with retrieval architectures, vector databases, and embedding models
• Familiarity with agent frameworks or workflow orchestration tools
• Experience with traditional ML frameworks (scikit-learn, PyTorch, TensorFlow)
• Prior work in healthcare, biotech, or other regulated industries

Benefits And Perks:

• Working alongside brilliant, kind, passionate and dedicated colleagues, in an empowering environment, toward a global vision, striving for a future in which transformative molecular diagnostics can help millions of patients
• Open, transparent culture that includes weekly Town Hall meetings
• The ability to indirectly or directly change the lives of hundreds of thousands patients
• Multiple m