SlipstreamJobs tracks this role from the company's public career site. Apply directly on the employer's site.
BillionToOne is a publicly traded genomics company transforming prenatal and cancer diagnostics through precision medicine. We're seeking a Senior Software Engineer to join our prenatal platform team and help scale our core systems to support rapid growth and enterprise workloads.
You'll work in a hybrid role (2-3 days/week onsite in Menlo Park) within a collaborative, interdisciplinary team of clinicians, computational biologists, and engineers. Your impact will span both targeted tools and large-scale product development across the full software lifecycle.
Key projects include: scaling and future-proofing core systems for enterprise workloads; building shared platform libraries and modular, domain-aligned services to reduce coupling and improve maintainability; driving architectural initiatives around service boundaries, data flows, and observability; and establishing foundational infrastructure and automation to strengthen deployment workflows and system health visibility.
Responsibilities: Design and operate scalable, high-availability backend services and APIs powering customer-facing experiences. Lead technical delivery across architecture, design, implementation, testing, deployment, and operations. Collaborate with product, design, and cross-functional engineering teams. Develop clean abstractions and platform APIs that simplify complex LIS workflows. Build and maintain secure, reliable AWS cloud infrastructure. Implement CI/CD pipelines, Infrastructure as Code, and automated provisioning. Embed observability and operational excellence through monitoring, logging, and alerting. Ensure scalability and maintainability as the platform grows. Foster a culture of ownership and technical excellence. Apply AI-assisted tooling to improve productivity and code quality.
Tech stack: Python, Django, FastAPI, PostgreSQL, React, TypeScript, AWS (ECS, S3, Batch, EC2, Lambda), Heroku, Salesforce, and AI-assisted coding tools (Cursor, GitHub Copilot, Claude Code).
Required: 5-7 years professional software development experience with proven delivery of complex projects. Deep expertise with Django and FastAPI. Strong system design and architecture capabilities, including domain-driven design. Familiarity with modern AI-driven development practices. Strong AWS foundation. Excellent communication and collaboration skills. Enthusiasm for in-person collaboration in Menlo Park.
