Senior Backend Engineer

We're building the future of preventive medicine. Molecular You analyzes blood biomarkers to help people understand their biological pathways, disease risks, and what they can actually do about it—before problems start. We work with clinicians and consumers across North America and are expanding globally.

We're a small team, which means the technical decisions you make today will be load-bearing for years. It also means you'll have real autonomy over architecture and won't spend your time getting sign-off from committees.

We seek an experienced Senior Backend Engineer to lead the design and implementation of mission-critical systems that power our platform. You will be responsible for core services including lab integrations that process thousands of biomarker results daily, analytics pipelines that generate personalized health insights, and APIs that serve web clients across multiple time zones. Your architectural decisions will directly impact our ability to scale effectively as we expand globally.

In this role, you will make strategic technical decisions that shape our platform's future. You will evaluate and recommend approaches to service architecture, determine appropriate synchronous versus asynchronous patterns, define data consistency requirements, and balance infrastructure investment with feature delivery. Beyond writing code, you will provide technical leadership by determining optimal solutions, identifying when problems can be solved without additional development, and establishing engineering best practices.

You'll spend your time:

• Designing, developing, and maintaining Ruby on Rails services for HIPAA-compliant patient data management, laboratory system integrations, and clinical recommendation engines
• Developing Elixir/Phoenix applications utilizing OTP patterns and supervision trees for high-concurrency, fault-tolerant systems requiring 24/7 reliability
• Designing and implementing event-driven architectures using Rabbit
  
  MQ, including defining service boundaries, selecting appropriate consistency models, and establishing retry and error-handling strategies
• Managing production infrastructure using Terraform, including capacity planning, high-availability architecture design, and cost optimization
• Conducting thorough code reviews focused on architectural quality, system design improvements, technical debt management, and mentoring junior team members
• Working across multiple repositories at varying maturity levels, making strategic decisions regarding legacy system refactoring, service consolidation, and microservice extraction
• Collaborating with Product and UX teams in six-week Shape Up development cycles, delivering features while managing underlying technical complexity
• Diagnosing and resolving complex distributed system issues including race conditions, message ordering problems, cascading failures, and performance bottlenecks in production environments
• Making critical technical decisions regarding database schema evolution, API versioning strategies, and infrastructure changes with significant cost and operational impact
• Participating in technical planning during cooldown periods, including technical debt assessment, infrastructure improvement initiatives, and cross-functional prioritization discussions

• Minimum 10 years of experience designing, building, and operating production backend systems with demonstrated expertise in architecting resilient, scalable solutions
• Extensive production experience with Ruby on Rails framework, including deep understanding of Rails conventions, best practices, and when custom solutions are warranted
• Proven experience developing production applications using Elixir/Phoenix, with solid understanding of OTP patterns, concurrency models, and appropriate use cases for Elixir-based architectures
• Hands-on production experience with message queues and event-driven architectures (Rabbit
  
  MQ strongly preferred), including implementing solutions for message ordering, idempotency, dead letter queue handling, and managing distributed messaging complexity
• Strong expertise in Terraform and infrastructure-as-code practices, with…