Software Engineer III - Full Stack; Backend-Focused, Core Platform Services

McKesson is an impact-driven, Fortune 10 company that touches virtually every aspect of healthcare. We are known for delivering insights, products, and services that make quality care more accessible and affordable. Here, we focus on the health, happiness, and well-being of you and those we serve - we care.

What you do at McKesson matters. We foster a culture where you can grow, make an impact, and are empowered to bring new ideas. Together, we thrive as we shape the future of health for patients, our communities, and our people. If you want to be part of tomorrow's health today, we want to hear from you.

Ontada's Engineering team builds iKnowMed (iKM), the leading Oncology EMR platform used by thousands of clinicians across the U.S. to manage cancer treatment from regimen ordering and chemotherapy scheduling to genomic result interpretation and clinical trial matching.

We are hiring a Software Engineer III (P3) to design and build well-scoped core services, shared frameworks, and platform components that domain teams depend on to deliver clinical applications. This is a backend-first full-stack role - you will spend the majority of your time in Java and Spring Boot building services, APIs, and event-driven integrations, with frontend work focused on building integration layers, enablement UIs, and end-to-end validation using React and Type Script.

You will work within established architectural standards, collaborate closely with senior engineers and architects, and focus on making your services reusable, well-documented, and easy for other teams to adopt. Your success is measured not only by what you build, but by how effectively other teams can build on top of it.

• Enjoy building the foundations that other teams build on
• Care deeply about API design, modularity, and developer experience
• Want to work in a high-impact healthcare domain where software directly affects patient outcomes
• Is ready to own well-scoped services end-to-end without needing to own the overall architecture

• Backend
  :
  Java, Spring Boot, JPA/Hibernate, Wild Fly (Jakarta EE)
• APIs
  : RESTful services, OpenAPI/Swagger
• Messaging
  :
  Apache Kafka (event-driven clinical workflows)
• Data
  :
  Oracle, Redis, Elasticsearch, Databricks
• Frontend
  :
  React, Type Script, Webpack Module Federation
• Observability
  :
  Dynatrace
• Infrastructure
  :
  Linux, Docker, CI/CD pipelines, Git
• Healthcare Standards
  : HL7v2, FHIR, C-CDA, SNOMED CT, LOINC, Rx Norm
• Quality
  : JUnit, Mockito, Integration Testing, Code Reviews
• Documentation
  :
  Markdown, Mermaid diagrams, API specifications

• Design and implement well-scoped backend services and shared components using Java and Spring Boot following established architectural patterns
• Build and maintain RESTful APIs with clear contracts, consistent error handling, and comprehensive documentation for easy domain team adoption
• Implement event-driven integrations using Kafka to connect clinical workflows across services (e.g., order state changes, lab result notifications, patient data sync)
• Build data integration and pipeline components to connect to Databricks for analytics and clinical data processing
• Write production-quality code against Oracle databases using JPA/Hibernate, focusing on query performance, transaction management, and data integrity
• Contribute to core services, shared libraries, and frameworks consumed by multiple clinical domain teams
• Ensure services are reusable, following consistent API patterns, event schemas, and extension points
• Collaborate with domain teams to understand integration needs and adapt platform services for rapid application development
• Adopt platform conventions for API versioning, event contracts, data handling, error taxonomy, and security standards
• Build frontend integration layers, admin UIs, and enablement interfaces using React and Type Script to expose platform capabilities to end users and domain teams
• Implement frontend changes to validate end-to-end clinical workflows, ensuring backend services function correctly through the full stack
• Develop unit, integration, and API-level tests; participate in peer code reviews adhering to coding,…