Senior Software Engineer

Silicon Valley (Redwood City to San Jose) • $100k - $150k • 0.2% - 0.5%

BillionToOne Inc

Role Location

  • Silicon Valley (Redwood City to San Jose)


  • $100k - $150k
  • 0.2% - 0.5%


26 - 50 people


1455 Adams Dr
Menlo Park, CA, 94025, US

Tech Stack

  • Python
  • Django
  • Heroku
  • AWS
  • Clojure
  • PostgreSQL

Role Description

BillionToOne (Y Combinator S17) is hiring #1 software engineer. This is an extremely impactful, cross-departmental, and product-oriented position that will make a real difference in people's lives from day 1. You will own engineering in a very fast-growth environment (we grew from ~5 to ~30 employees in the past year) with the opportunity to grow and lead an engineering team in ~2 years. Reports directly to CTO. No biotech experience is necessary, but a growth mindset & end-to-end product ownership is key.

We apply bioengineering and machine learning principles to diagnostics in order to build truly quantitative molecular tests. Our QCT platform improves the resolution of cell-free DNA testing by >1000x fold and enables novel tests for both prenatal and oncology care. As engineer #1, you will work directly with the CTO to build backend infrastructure, bioinformatics data processing pipelines, laboratory automation tools, and web-based tools to communicate genetic results to patients.


  • 2-5 years as a full-stack engineer touching frontend, database, backend
  • Very strong Python expertise
  • Deep knowledge of web technologies: REST, relational databases, HTTP, javascript
  • Experience with a web framework in Python, e.g. Django or Flask
  • Strong desire to make an impact both through many small tools and large product development in a fast-paced environment

About BillionToOne Inc

We've developed a DNA molecular counter with 1000x better precision. Our DNA technology underpins the first and only non-invasive prenatal test for cystic fibrosis, sickle cell disease, and other severe inherited disorders.

Company Culture

  1. Collaborative. We are a highly disciplinary team comprised of engineers, PhD scientists, lab scientists, product, marketing, and commercial. Everyone participates in discussions and learns from each other.

  2. Kind. No brilliant jerks are allowed.

  3. High Impact. We empower people to make decisions, use high-leverage tools, and solve big problems.

  4. Patient focused. Every decision is viewed through the lens, What is best for the patient?

Interested in this role?
Skip straight to final-round interviews by applying through Triplebyte.

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