AI-assisted dev tools (Cursor, Copilot, Claude Code) integrated into engineering workflow with unlimited access to latest AI tools and models.
BillionToOne (NASDAQ: BLLN) seeks a high-performing Senior Software Engineer for their dynamic software engineering team. This hybrid role involves collaborating with clinicians, computational biologists, and other engineers to robustly scale personalized genomic medicine to millions of patients. You will build seamless digital experiences for clinicians and patients accessing genetic testing, digitize paper-based workflows at busy OBGYN clinics, enable portable electronic medical records for care transfer, and infuse joyful experiences into pregnancy. Tech stack: Python, Django, Postgres, React, TypeScript, AWS, Salesforce, and AI-assisted coding tools (Cursor, GitHub Copilot, Claude Code). Responsibilities include building robust applications using React, TypeScript, Django, Postgres; collaborating with product design and management teams; fostering knowledge sharing through mentorship; writing comprehensive unit tests; demonstrating ownership of end-to-end project delivery; championing engineering excellence through best practices and code reviews; applying security and compliance mindset for patient data protection. Requirements: 5+ years of professional software development experience, deep expertise in TypeScript, React, CSS-in-JS libraries, implemented frontend architecture (component systems, npm workspaces, Storybook, Playwright testing), Django web framework experience, familiarity with AI-driven development practices. Nice-to-haves: startup or entrepreneurial background, zero-to-one product development experience, healthcare data standards knowledge (FHIR, HL7), interest in LLMs. Revenue grew from $0 to approximately $300M in four years, with guidance of $415-430M for 2026. Over 1 million tests processed. Forbes Best Startup Employers 2024 & 2025. Benefits include 100% employee premium coverage on select medical plans, 80% dependent coverage, 16 weeks paid family leave, 4% 401(k) match, daily catered lunch, on-site gym, free EV charging, unlimited access to latest AI tools and models.