Senior Software Engineer

ShortList is recruiting a Senior .NET Engineer for an early-stage healthcare technology company in Austin, TX to build a clinical reasoning engine that closes the diagnostic capability gap between mid-level providers and physicians. The Senior .NET Engineer will be the first engineering hire, working directly with the founders to accelerate development, build integrations with major Electronic Health Record (EHR) systems, and ultimately help translate a proprietary clinical reasoning engine from concept into production-grade systems. This is not a stable seat at a large organisation. We are looking for a senior engineer who is comfortable with ambiguity, self‑organising by default, and genuinely motivated by the mission of expanding diagnostic access to underserved populations. Key Requirements for the Senior .NET Engineer 5 or more years of professional C#.NET experience, with current familiarity with .NET 9 Strong ASP.NET Core skills, including middleware, authentication, and dependency injection Working knowledge of OAuth 2.0 and OpenID Connect (OIDC) Strong REST API and JSON serialisation skills Solid Git and pull request workflow, comfortable with async collaboration as the default Prior Fast Healthcare Interoperability Resources (FHIR) experience is highly advantageous, even at sandbox level Comfortable working with AI pair‑programming tools Key Skills required for the Senior .NET Engineer Able to build and deliver a SMART on FHIR launch flow against a major Electronic Health Record sandbox within the first quarter Capable of implementing OAuth 2.0 and OpenID Connect authorisation with patient context Experienced in building FHIR clients and mappers across core resource types, including Patient, Condition, Observation, and Encounter Able to write FHIR resources, including Diagnostic Report and Service Request Capable of building Clinical Decision Support Hooks services from the ground up Able to design and implement multi‑tenant configuration and sandbox test harnesses Detail‑oriented, with a track record of clear commits, well‑structured pull requests, and respect for clinical and regulatory boundaries Comfortable shaping architecture decisions at an early stage, not just executing against a defined spec Candidates from Electronic Health Record vendors, healthcare integration firms, and adjacent regulated‑industry backgrounds are particularly encouraged to apply. Any experience with the following is a plus: Firely .NET SDK, Substitutable Medical Applications and Reusable Technologies (SMART) on FHIR launch flow implementation, Clinical Decision Support (CDS) Hooks implementation, or a background at Epic, Oracle Health, Cerner, or Athenahealth. This is a Hybrid role in Austin with 1-2 days per week in office. Candidates must have the right to work in the United States and we cannot currently provide sponsorship. #J-18808-Ljbffr