Senior Software Engineer, Frontend

BillionToOne 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.

BillionToOne 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. BillionToOne 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 BillionToOne 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, BillionToOne 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 BillionToOne and its groundbreaking work, please visit our website at www.billiontoone.com.

We are currently looking for a high-performing Senior Software Engineer, Frontend to join our dynamic software engineering team. Software engineers at BillionToOne 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.

Projects you may work on include:

• Build a seamless digital experience so clinicians and patients across a diversity of care centers and socioeconomic status can have access to BillionToOne’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

Technologies We Use:

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

Responsibilities:

• 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 components and modules. Highly skilled in writing technical documentation and validation reports that assure correct functionality of medical informatics systems.
• Demonstrate a strong sense of ownership and take responsibility for end-to-end project delivery. The ideal candidate will thrive in an environment where they have the autonomy to make informed decisions and take the initiative to drive projects forward.
• Collaborate cross-functionally, actively seeking input from team members and fostering a positive and inclusive work environment.

Requirements:

• 5+ years of professional software development experience with a proven track record of delivering complex projects and adhering to best practices.
• Expertise in frontend engineering using modern libraries like Typescript, React, and HTMX
• Familiarity with modern AI-driven development practices and tools.
• Excellent communication and collaboration skills, with the ability to work effectively in a team-oriented environment.
• Proven track record of building products and features from conception to deployment, showcasing your ability to innovate and deliver results
• Excited about working in-person with our team in Menlo Park

Nice-to-haves:

• Experience in healthcare-related software or a passion for improving healthcare systems.
• Familiarity with healthcare data standards, such as FHIR and HL7.
• Experience leveraging AI-assisted coding and debugging tools.
• Experience building AI agents, fine-tuning machine learning models, or deploying LLM-based applications.

If you’re passionate about creating technology that transforms healthcare and thrive in a collaborative, fast-paced environment, we’d love to hear from you.

Benefits And Perks:

• Working with a team of ‘rockstars’ who bring out the best in everyone
• Open, transparent culture that includes weekly Town Hall meetings
• The ability to indirectly or directly change the lives of hundreds of thousands patients
• Multiple medical benefit options; employee premiums paid 100% of select plans, dependents covered at 80%
• Extremely generous Family Bonding Leave for new parents (16 weeks, paid at 100%)
• Retirement savings program including a 4% Company match
• Free daily on-site lunches provided from top eateries
• Latest and greatest hardware (laptop, lab equipment, facilities)
• A variety of perks on campus (state of the art gym, restaurant)
• Free on-site EV charging (compatible with all EVs, including Tesla)

At BillionToOne, we are proud to offer a combination of a (1) base pay range (actual amount offered is based on experience and salary/equity options split that the candidate chooses), (2) generous equity options offering, (3) corporate bonus program, on top of (4) industry leading company benefits (free healthcare options, 401k match, very generous fully paid parental leave, etc.).

For this position, we offer a total compensation package of up to $321,120 per year, including a base pay range of $193,800 - $214,200 per year.

BillionToOne is an equal opportunity employer. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.