---
title: "Oracle Health (Cerner)"
description: "Local, stateful API emulators for healthcare and life science development. FHIR, SMART on FHIR, EHRs, payers, and life science APIs, without PHI. Synthetic data only."
canonical_url: "https://www.emuhealth.dev/docs/cerner"
---
# Oracle Health (Cerner)

An emulator of the Oracle Health (Cerner) Millennium FHIR R4 API for apps that will connect to Millennium. It runs on `http://localhost:4109` by default and serves the full [FHIR R4](/docs/fhir) server under Millennium's tenant URL shape, with the same generated synthetic patients. emuhealth is not affiliated with Oracle, and the emulator holds synthetic data only.

```bash
npx emuhealth --service cerner
curl 'http://localhost:4109/r4/5e7e0000-0000-4000-8000-000000000001/Patient/syn-patient-001'
```

## URLs

The emulator has one synthetic tenant, `5e7e0000-0000-4000-8000-000000000001`.

| What | URL |
|------|-----|
| FHIR base | `http://localhost:4109/r4/{tenant}` |
| SMART discovery | `http://localhost:4109/r4/{tenant}/.well-known/smart-configuration` |
| Authorize (provider persona) | `http://localhost:4109/tenants/{tenant}/protocols/oauth2/profiles/smart-v1/personas/provider/authorize` |
| Authorize (patient persona) | `.../smart-v1/personas/patient/authorize` |
| Token | `.../smart-v1/token` |
| EHR launch simulator | `http://localhost:4109/r4/{tenant}/auth/launch?launch_uri=<your app launch URL>` |
| Inspector | `http://localhost:4109/_inspector` |

Everything in the [FHIR R4 docs](/docs/fhir) works under the FHIR base. Other tenant paths return `404`.

## OAuth and personas

SMART App Launch (standalone and EHR launch, PKCE, v1 and v2 scopes, `openid fhirUser`) works as on the [FHIR R4 server](/docs/fhir#smart-app-launch). The patient persona's authorize URL redirects to the same flow, which shows the patient picker for `launch/patient`. Token responses add `tenant` and, when a practitioner signs in, `username` and `user` with the practitioner's id.

## System accounts

Millennium system accounts get tokens with the client credentials grant and a client secret, not a signed JWT. Register the account with a `client_secret` (and optionally a `scope` limit), then call the token endpoint with Basic auth:

```bash
curl -u my-system-account:synthetic-secret \
  -d grant_type=client_credentials -d scope=system/Patient.read \
  http://localhost:4109/tenants/5e7e0000-0000-4000-8000-000000000001/protocols/oauth2/profiles/smart-v1/token
```

Signed JWT assertions (SMART Backend Services) work too, for clients registered with keys.

## Required search parameters

Like Millennium, searches on clinical types need at least one identifying parameter, or they get `400` with an OperationOutcome that lists the options:

| Type | One of |
|------|--------|
| Observation, Condition, DiagnosticReport, DocumentReference, Procedure, CarePlan | `patient`, `subject`, `_id` |
| AllergyIntolerance, MedicationRequest, Immunization, Goal, CareTeam, Device | `patient`, `_id` |
| Encounter | `patient`, `subject`, `_id`, `identifier` |
| Patient | `_id`, `identifier`, `name`, `family`, `given`, `birthdate`, `phone`, `email`, `address-postalcode` |
| Provenance | `target`, `_id` |

Other types, such as Practitioner and Organization, search without restrictions.

## Seed config

The `cerner` key takes the same options as `fhir` (`generate`, `resources`, `smart`, `terminology`):

```yaml
cerner:
  smart:
    clients:
      - client_id: my-millennium-app
        redirect_uris: ["http://localhost:3000/callback"]
      - client_id: my-system-account
        client_secret: synthetic-secret
        scope: system/Patient.read system/Observation.read
```