BillionToOne Inc.

BillionToOne is a next‑generation molecular‑diagnostics company that is reshaping the way we detect disease by measuring disease‑specific DNA with unprecedented precision. Founded by scientists who previously pioneered high‑throughput sequencing, the company’s core technology – Quantitative Counting Technology (QCT) – counts individual copies of circulating DNA in a sample, providing a sensitivity that is more than a thousand‑fold better than conventional tests. This leap in resolution has enabled the design of flagship products such as Unity, the only non‑invasive prenatal screening test that can evaluate common and severe recessive gene disorders, chromosomal abnormalities, fetal sex, and antigen status from a single maternal blood draw, and Northstar, a liquid‑biopsy platform that not only identifies tumors but also monitors treatment response in real time. These solutions empower clinicians to make rapid, data‑driven decisions that previously required invasive procedures. BillionToOne’s products are being adopted by hospitals and laboratories worldwide, and the company has already impacted over half a million patients globally.

Beyond product innovation, BillionToOne has built a culture that reflects the boldness of its science. The company is headquartered in Menlo Park and maintains a hybrid workforce that balances on‑site collaboration with remote flexibility for employees across the U.S. This model supports a diverse talent pool that spans software engineering, bioinformatics, product, regulatory, and clinical roles. The organization emphasizes transparency, autonomy, and a relentless focus on patient outcomes. Employees routinely report a sense of purpose, with 100 % expressing willingness to go the extra mile. The leadership team brings experience from biotech, medical devices, and big‑tech, fostering a start‑up mentality that encourages rapid iteration and cross‑disciplinary feedback loops.

BillionToOne’s growth trajectory has been fueled by substantial investment. In June 2024, the company closed a 130 million Series D that raised its valuation to over 1 billion, with investors including Sequoia Capital, Hummingbird, Adams Street Partners, Neuberger Berman, Baillie Gifford, and Premji Invest. The raised capital supports accelerated scale‑up of production, regulatory approvals, and expansion of the cloud infrastructure that runs both the Unity and Northstar platforms. The company also maintains several active patents, underscoring the defensibility of its technology.

The team’s commitment to innovation extends to its technology stack. The front‑end is built with React and TypeScript, leveraging component libraries, Storybook for design systems, and Playwright for end‑to‑end testing. The back‑end uses Python and Django, supported by PostgreSQL for data persistence and Amazon Web Services for a globally distributed, highly available architecture. The company also explores AI‑assisted coding tools and LLM integrations to streamline developer productivity. Employees are encouraged to experiment with new technologies, as evidenced by the recent adoption of Terraform for infrastructure as code, automated CI/CD pipelines, and modern data‑visualization frameworks.

Equity and benefits are carefully structured to reward long‑term contributions. New hires receive competitive salaries (USD 187,272‑208,080 annually for senior software engineers) coupled with equity stakes that vest over four years. The benefits package is comprehensive, including unlimited paid time off, extended family leave, medical and dental coverage, 401(k) match, and a learning stipend for professional development. Remote work, on‑site wellness facilities, and a flexible schedule are additional perks.

Finally, BillionToOne is a company that invites individuals who are not only technically skilled but also deeply passionate about using science to create tangible, life‑changing solutions. By joining the team, engineers become part of a mission to detect diseases at a single‑molecule level, pushing the boundaries of what diagnostics can achieve. The company’s open, inclusive environment and its blend of cutting‑edge science with rigorous engineering make it an exciting place to shape the future of precision medicine.