BillionToOne (YC S17) is a molecular diagnostics company with 300+ employees, unicorn status, over $400M in funding and $125M ARR. Their QCT technology enhances disease detection resolution by over a thousandfold using cell-free DNA.
As Senior Software Engineer, Oncology, you will:
- Design and develop services, data pipelines, and user interfaces
- Build backend systems including test ordering databases and third-party integrations
- Write comprehensive unit, integration, and end-to-end tests
- Author technical documentation for medical informatics systems
- Drive end-to-end project delivery with ownership mentality
Required Qualifications:
- 5+ years software development experience
- Expertise in Python backend frameworks (Django/Flask)
- Strong AWS foundation (ECS, S3, Batch, EC2, Lambda)
- Familiarity with modern AI-driven development practices
- Proven product delivery track record
Nice-to-Have:
- Healthcare software experience
- Startup/high-growth company background
- FHIR and HL7 familiarity
- Experience leveraging AI-assisted coding and debugging tools
- AI agent building or LLM deployment experience
Tech Stack: Python, Django, Flask, PostgreSQL, AWS, Alpine.js, HTMX, Salesforce, and emerging AI-assisted coding environments (e.g., Cursor, GitHub Copilot, OpenAI)
Salary: $190,081 - $211,201 base; $307,321 total compensation
Hybrid: 2-3 days/week onsite in Menlo Park, CA
Benefits:
- 100% employee premium medical coverage (select plans)
- 16-week fully paid parental leave
- 4% 401(k) match
- On-site gym, dining, EV charging
- Daily catered lunches