Connect to the Cerner/Oracle Health Ignite FHIR sandbox and make authenticated API calls

Steps

1. Register at code.cerner.com (now Oracle Health Developer Portal) and create a new application to receive a client_id for the Ignite FHIR sandbox.
2. Use the Cerner authorization endpoint discovered from the FHIR server's .well-known/smart-configuration for the sandbox environment (e.g., the millennium sandbox base URL).
3. Follow the standard SMART on FHIR standalone or EHR launch flow using the client_id obtained from the portal; Cerner supports both SMART v1 and v2 flows.
4. Query the sandbox FHIR R4 base URL with the obtained access token; Cerner's Ignite FHIR R4 endpoint follows standard FHIR R4 conventions with Cerner-specific implementation notes documented in their Millennium FHIR API docs.
5. Check the Cerner FHIR API documentation for supported resources, search parameters, and any Cerner-specific extensions or identifier systems for the Millennium platform.
6. Use Cerner's open sandbox patient IDs (documented in their developer portal) for test queries; the open sandbox allows unauthenticated read access to a limited set of synthetic data.