Senior Software Engineer, Frontend

Billion To One is a next-generation molecular diagnostics company dedicated to developing powerful and accurate diagnostic tests that are accessible to all. Our innovative QCT molecular counting technology significantly enhances the resolution of disease detection using cell-free DNA by over a thousandfold. This groundbreaking technology is integral to our product offerings, including one of our flagship products, Unity Complete™
The only non-invasive prenatal screen capable of assessing fetal risk for both common recessive conditions and aneuploidies from a single maternal blood sample. Leveraging the same molecular counting technology, we've expanded our impact into oncology in 2023 with a pioneering liquid biopsy test, Northstar, that combines treatment selection with monitoring. To date,
over 500,000 patients have benefited from our innovative and precise diagnostic tests
, and our Annual Recurring Revenue (ARR) has grown from $0 to $125 million in the last ~4 years.

Billion To One  has successfully raised close to $400 million in funding, with a notable $130 million Series D round completed in June 2024, resulting in a company valuation of over $1 billion. This funding has come from prestigious global institutional investors, including Hummingbird, Adams Street Partners, Neuberger Berman, Baillie Gifford, and Premji Invest. Billion To One  has recently been recognized by Forbes as one of America's Best Startup Employers for 2024, highlighting the company's exceptional work environment and commitment to innovation.

Our team has grown significantly and we now proudly employ over 400 highly skilled individuals. Despite substantial growth, we have successfully maintained the unique culture that has defined Billion To One  from inception, continuing to cultivate a team that is not only diverse and passionate but also innovative. Headquartered in Menlo Park, California, with an additional facility in Union City, California, Billion To One  remains at the forefront of significant advances in molecular diagnostics, evidenced by the recent announcement of clinical outcomes data for its Unity Fetal Risk Screen and new advancements in cancer diagnostics.

For more detailed information about Billion To One  and its groundbreaking work, please visit our website at

We are currently looking for a high-performing Senior Software Engineer, Frontend to join our dynamic software engineering team. Software engineers at Billion To One  work in highly collaborative and interdisciplinary teams of clinicians, computational biologists, and other engineers to robustly scale personalized genomic medicine to millions of patients. If you have experience performing in a full life-cycle development, love seeing your work positively affect your colleagues and patients, and thrive in a fast-paced entrepreneurial environment, this could be a great opportunity for you.

In this role, you can have an impact both through many small tools and large product development.
This role is a hybrid (onsite 2-3 days/week) position.

• Build a seamless digital experience so clinicians and patients across a diversity of care centers and socioeconomic status can have access to Billion To One ’s highly complex genetic testing
• Help digitize laborious and error-prone paper-based workflows at busy Oncology and Prenatal clinics
• Enable better transfer of care through portable electronic medical records

Python, Django, Postgres, AWS, React, Typescript, Alpine.js, HTMX, Salesforce, and emerging AI-assisted coding environments (e.g., Cursor, Git Hub Copilot, OpenAI).

• Collaborate with talented engineers to design and develop our backend services, data processing pipelines, and interfaces, driving innovation and efficiency
• Build user-facing frontend features to optimize performance and reliability, enhancing overall user experience.
• Demonstrate a creative and out-of-the-box mindset, offering innovative solutions and approaches to complex technical challenges.
• Prioritize quality by writing comprehensive unit / integration / end-to-end tests and ensuring superior test coverage across all…