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As an app developer, you are obliged to be familiar with and practice principles for responsible healthcare app development. For any app that uses the Materials, as defined in the Terms of Use, you and your apps should practice the following guidelines. If you have reason to suspect your app is not following the guidelines or is misbehaving and would like Epic to suspend use of your app until the issue is resolved, or if you have any questions about these guidelines, please contact us at open.epic.com/Home/Contact.
Epic recommends apps be well-behaved, adhering to the following principles:
The app should reasonably adhere to usability standards that impact patient safety, specifically safety-enhanced design(g)(3) and accessibility-centered design.(g)(5)
If the app allows an end user to search for a patient, the app should collect enough information from the end user to uniquely identify the correct patient or display enough information to the end user to enable the end user to uniquely identify the correct patient.(g)(7)
If the app is launched within an Epic patient workspace for patient-specific workflows, the app should maintain the patient identity within the session. If the app is launched separately for patient-specific workflows, the app should prominently display the patient’s identifying information to avoid any confusion by the end user about which patient’s record she is interacting with.
Because it is possible that your app’s connectivity to an Epic Community Member’s Epic system may be interrupted, you should clearly inform users of your app that it might not always be available to them and that they should not rely on it in an emergency.
The app should encrypt data stored in non-volatile storage using industry-standard encryption algorithms, such as AES-128 or higher. If encryption keys must be written to disk, then the app should make appropriate use of key storage functionality provided by the host platform/operating system and require the administrative user to authenticate to gain access to the encryption keys.
The app should support securing, sending, or receiving data secured with the TLS 1.2 or higher encryption protocol. The app should verify that the server’s TLS certificate is valid and signed by a certificate authorized, recognized, and trusted by the host operating system.
Data exchange between your app and Epic’s APIs and between your app and any other system should be secured with industry standard encryption while in transit,(d)(9) and use authentication and authorization protocols.(d)(1)
The preferred mechanism for apps to authenticate with Epic is OAuth 2.0. Use of other authentication mechanisms, such as HTTP Basic Authentication, may be appropriate in certain circumstances.
The app should protect authentication credentials provided by Epic or Epic Community Members, such as user names, user passwords, access tokens, or refresh tokens. Credentials used to access Epic Community Member’s Epic systems should be unique to each Epic Community Member, should only be used in conjunction with Epic APIs, and should never be passed to non-Epic systems. If the app needs to persist this data to non-volatile storage, it should use approved secure storage functionality provided by the host platform/operating system.
If the app prompts the user for credentials such as passwords or biometric data, or other sensitive information such as credit card numbers or financial account information, you should take care to protect this data. If the data must be written to non-volatile storage, it should never be stored in clear text. The app should make use of one-way hashing algorithms such as SHA-256 or secure storage functionality provided by the host platform/operating system to persist this data. Your app should secure all data on an end-user’s device(d)(7) (d)(8), and enforce inactivity time-outs.(d)(5)
You should keep your apps’ client identifiers confidential and should not disclose them to any other party or use them for any other purpose. Each of your apps should have its own unique client identifier. Apps that are confidential clients and using refresh tokens should keep their client secret safe.
The app is expected to leverage well-known, established software packages to perform low-level cryptography and authentication operations. Authentication and cryptography software should be actively maintained and have published processes for reporting and responding to security vulnerabilities. Apps are strongly discouraged from implementing custom cryptography or authentication functionality.
You should evaluate your app for security vulnerabilities using resources such as OWASP Top 10 and address any applicable vulnerabilities in your app.
You should provide users (e.g., the Epic Community Member or end user that uses your app) with a clear and understandable data use or privacy policy that includes an explanation of any data elements that your app obtains from or writes to an Epic Community Member’s Epic system and how and where that data is used. If you or your app do any of the following, then, for each, you should disclose such action to, and obtain appropriate consent from, the user: obtaining data from or writing data to an Epic Community Member's Epic system, retaining data processed by your app (including the length of time for which the data is retained), making any secondary uses of the data, providing any other party or product any access to the data, transferring the data to any other party or product.
A patient-facing app should obtain such consent from end users and provide end users with an option to decline consent or to revoke their consent in the future. A patient-facing app should not circumvent the display of any end user authentication or authorization mechanisms from Epic or any Epic Community Member.
When you use, retain, or distribute data that you obtained from an Epic Community Member’s Epic system, you should document who used, retained, or distributed what data, when they did so, and for what purpose they did so. You should provide users access to that documentation upon request.
You should provide clear and prominent notice to users how they may stop the app from reading, writing, or retaining data.
Your app should be properly tested and should be stable, predictable, and not negatively impact clinical operations or patient safety. Your app should not generate excessive load on a user’s systems or an Epic Community Member’s systems, or cause other systems to behave inaccurately or unexpectedly. Whenever possible, the app should be tested in a non-production environment to gauge the impact on the Epic Community Member’s systems prior to release in production.
The app should appropriately manage end users’ assumptions and expectations of healthcare software to avoid negative outcomes. If the app permits end users to input data that is typically input and stored in an Epic system, or if the app uses an API to look up data from an Epic system and also permits end users to edit that data, then end users are likely to assume or expect that the app will file the new or updated data to Epic. If the app facilitates part of a workflow, then end users are likely to assume or expect the app to trigger downstream steps in the workflow (e.g., trigger a message to another end user, trigger an interface message, etc.).
You and your apps should not corrupt or otherwise cause material inconsistencies in any data used by your apps.(d)(2)
Direct access to Epic’s software (including an Epic Community Member’s system) is not required to develop, test, deploy, or support your product or service. You can test your product or service through the open.epic/Epic on FHIR sandbox or by working with a particular Epic Community Member. Direct access to Epic’s software can only be granted by both an Epic Community Member and Epic.
You should not misrepresent products, product capabilities, business relationships, timelines, or anything else related to Epic or open.epic in any way. This includes but is not limited to accurate representation of
45 CFR 170.315 (d)(1) (Authentication, Access Control, Authorization): "Verify against a unique identifier(s) (e.g., username or number) that a user seeking access to electronic health information is the one claimed; and [...] establish the type of access to electronic health information a user is permitted based on the unique identifier(s) provided"↩
45 CFR 170.315 (d)(2) (Auditable Events and Tamper-resistance): "The health IT records actions pertaining to electronic health information [...] when health IT is in use; changes to user privileges when health IT is in use; and records the date and time [each action occurs]. [...] The health IT records the audit log status [...] when the audit log status is changed and records the date and time each action occurs. [...] The health IT records the information [...] when the encryption status of locally stored electronic health information on end-user devices is changed and records the date and time each action occurs.”↩
45 CFR 170.315 (d)(5) (Automatic Access Time-out): "Automatically stop user access to health information after a predetermined period of inactivity. [...] Require user authentication in order to resume or regain the access that was stopped."↩
45 CFR 170.315 (d)(7) (End-user Device Encryption): "Technology that is designed to locally store electronic health information on end-user devices must encrypt the electronic health information stored on such devices after use of the technology on those devices stops [or] technology is designed to prevent electronic health information from being locally stored on end-user devices after use of the technology on those devices stops."↩
45 CFR 170.315 (d)(8) (Integrity): "Verify [...] upon receipt of electronically exchanged health information that such information has not been altered."↩
45 CFR 170.315 (d)(9) (Trusted Connection): "Health IT needs to provide a level of trusted connection using either 1) encrypted and integrity message protection or 2) a trusted connection for transport."↩
45 CFR 170.315 (g)(3) (Safety-enhanced Design): "User-centered design processes must be applied to each capability technology."↩
45 CFR 170.315 (g)(5) (Accessibility-centered Design): "The use of a health IT accessibility-centered design standard or law in the development, testing, implementation and maintenance of that capability must be identified."↩
45 CFR 170.315 (g)(7) (Application Access - Patient Selection): " The technology must be able to receive a request with sufficient information to uniquely identify a patient and return an ID or other token that can be used by an application to subsequently execute requests for that patient’s data."↩
45 CFR 170.315 (g)(8) (Application Access - Data Category Request): "Respond to requests for patient data (based on an ID or other token) for each of the individual data categories specified in the Common Clinical Data Set and return the full set of data for that data category (according to the specified standards, where applicable) in a computable format."↩
45 CFR 170.315 (g)(9) (Application Access - All Data Request): "Respond to requests for patient data (based on an ID or other token) for all of the data categories specified in the Common Clinical Data Set at one time and return such data (according to the specified standards, where applicable) in a summary record formatted [...] following the CCD document template."↩
Epic on FHIR enables Epic community members to download client IDs for applications registered on the Epic on FHIR website. In order to download client IDs, each Epic community member must have a designated point person with the security to download an app's client IDs on behalf of the organization. The community member's point person for Epic on FHIR is the same person/people as for App Orchard (i.e. the App Orchard Point Person).
The sections below walk through an overview of:
A more in-depth version of this guide can be accessed by signing in.
To download a client ID from Epic on FHIR, the point person of an Epic community member can log in to the Epic on FHIR website using their UserWeb credentials.
Epic Community Members log in to the Epic on FHIR website with UserWeb credentials:
A community member who doesn't have a UserWeb account can create one using a work email address on the UserWeb registration page. App developers should log in using the 'Epic on FHIR' login option.
App developers do not need to register or agree to terms to view the API specifications on the Epic on FHIR website. To view tutorials, use the sandbox, or obtain client IDs, the developer may register and agree to the Epic on FHIR terms.
When a developer registers an app, the website creates an app record in the Epic database and assigns the app production and non-production client IDs. After the developer has completed development and testing, they can mark their app ready for production use. An app developer must provide an Epic Community member with their app’s Client ID to allow them to download the app. Apps that use backend OAuth 2.0 or refresh tokens must also have public keys and/or client secrets, with separate sets per each customer or environment.
Before Epic community members start the request process, they should first determine if an app would be a good fit for them. This consists of working with their Epic technical coordinator (TC) to research available integrations, verifying the requisite Epic products and interfaces are in place, and evaluating the potential new costs of using the app. When an Epic community member has committed to moving forward with an app registered on the Epic on FHIR website, a kickoff call between stakeholders from each organization should take place regarding key project details.
Community members who wish to use the FHIR APIs with a third-party application registered on the Epic on FHIR website must sign the open.epic API Subscription Agreement. Members do not need this license in order for their patients to use MU3 apps that used open.epic to develop, test, and register their products. Community members can view downloaded apps and download new apps from the Epic on FHIR website. The app’s client ID (either Production or Non-Production) is required for downloading and must be obtained from the developer.
Epic does not endorse, certify, or verify the integrity, safety, performance, or practices of the developers who use Epic on FHIR or their software.
Applications must secure and protect the privacy of patients and their data. To help meet this objective, Epic supports using the OAuth 2.0 framework to authenticate and authorize applications.
OAuth 2.0 enables you to develop your application without having to build a credential management system. Instead of exposing login credentials to your application, your application and an EHR's authorization server exchange a series of authorization codes and access tokens. Your application can access protected patient data stored in an EHR's database after it obtains authorization from the EHR's authorization server.
To use OAuth 2.0 to authorize your application's access to patient information, some information needs to be shared between the authorization server and your application:
client_id: The client_id identifies your application to authentication servers within the Epic community and allows you to connect to any organization.redirect_uri: The redirect_uri confirms your identity and is used to validate and redirect authentication requests that originate from your application. Epic's implementation allows for multiple redirect_uris. redirect_uri is not needed for backend services using the client_credentials grant type.
You can register your application for access to both the sandbox and Epic organizations here. You'll provide information to us, including one or more redirect_uris, and Epic will generate a client_id for you.
Apps can be launched from within an existing EHR or patient portal session, which is called an EHR launch. Alternatively, apps can be launched standalone from outside of an existing EHR session. Apps can also be backend services where no user is launching the app.
EHR launch (SMART on FHIR): The app is launched by the EHR calling a launch URL specified in the EHR's configuration. The EHR launches the launch URL and appends a launch token and the FHIR server's endpoint URL (ISS parameter) in the query string. The app exchanges the launch token, along with the client identification parameters to get an authorization code and eventually the access token.
Standalone launch: The app launches directly to the authorize endpoint outside of an EHR session and requests context from the EHR's authorization server.
Backend services: The app is not authorized by a specific person and likely does not have a user interface, and therefore calls EHR web services with system-level authorization.
Desktop integrations through Subspace: The app requests access to APIs directly available on the EHR’s desktop application via a local HTTP server.
Considerations for native apps: Additional security considerations must be taken into account when launching a native app to sufficiently protect the authorization code from malicious apps running on the same device. There are a few options for how to implement this additional layer of security:
Starting in the August 2019 version of Epic, the Epic implementation of OAuth 2.0 supports PKCE and Epic recommends using PKCE for native mobile app integrations. For earlier versions or in cases where PKCE cannot be used, Epic recommends the use of Universal Links/App Links in lieu of custom redirect URL protocol schemes.
The app you build will list both a production Client ID and a non-production Client ID. While testing in the Epic on FHIR sandbox, use the non-production Client ID.
The base URL for the Current Sandbox environment is:
https://fhir.epic.com/interconnect-fhir-oauth/Contents
Your app is launched by the EHR calling the launch URL which is specified in the EHR's configuration. The EHR sends a launch token and the FHIR server's endpoint URL (ISS parameter).
launch: This parameter is an EHR generated token that signifies that an active EHR session already exists. This token is one-time use and will be exchanged for the authorization code.
iss: This parameter contains the authorization server's FHIR endpoint URL.
To determine which authorize and token endpoints to use in the EHR launch flow, you should make a GET request to the metadata endpoint which is constructed by taking the iss provided and appending /metadata.
If no Accept header is sent, the document returns XML by default. If an Accept header is sent with a value of application/json, application/fhir+json, or application/json+fhir, the document returns JSON.
Here's an example of what a full metadata request might look like.
GET https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/metadata HTTP/1.1
Accept: application/fhir+jsonHere is an example of what the authorize and token endpoints would look like in the metadata response.
"extension": [
{
"url": "http://fhir-registry.smarthealthit.org/StructureDefinition/oauth-uris",
"extension": [
{
"url": "authorize",
"valueUri": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2/authorize"
},
{
"url": "token",
"valueUri": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token"
}
]
}
]
In some cases when making your request to the metadata endpoint, you'll also need to include additional headers to ensure the correct token and authorize endpoints are returned. This is because in Epic, it is possible to configure the system such that the FHIR server's endpoint URL, provided in the iss parameter, is overridden on a per client ID basis. If you do not send the Epic-Client-ID HTTP header with the appropriate production or non-production client ID associated with your application in your call to the metadata endpoint, you can receive the wrong token and authorize endpoints. Additional CORS setup might be necessary on the Epic community member's Interconnect server to allow for this header.
Here's an example of what a full metadata request might look like with the additional Epic-Client-ID header.
GET https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/metadata HTTP/1.1
Accept: application/fhir+json
Epic-Client-ID: 0000-0000-0000-0000-0000
Your application now has a launch token obtained from the initial EHR launch as well as the authorize endpoint obtained from the metadata query. To exchange the launch token for an authorization code, your app needs either to redirect (using HTTP GET) from the launch URL to the authorize endpoint and append the following querystring parameters, or, in Epic version November 2020 and later, make an HTTP POST request to the authorize endpoint that includes the following parameters in the body of the request.
response_type: This parameter must contain the value "code".client_id: This parameter contains your web application's client ID issued by Epic. redirect_uri: This parameter contains your application's redirect URI. After the request completes on the Epic server, this URI will be called as a callback. The value of this parameter needs to be URL encoded. This URI must also be registered with the EHR's authorization server by adding it to your app listing.scope: This parameter describes the information for which the web application is requesting access. Starting with the Epic 2018 version, a scope of "launch" is required for EHR launch workflows. Starting with the November 2019 version of Epic, OpenID Connect scopes are supported, specifically the "openid" scope is supported for all apps and the "fhirUser" scope is supported by apps with the R4 (or greater) SMART on FHIR version selected.launch: This parameter is required for EHR launch workflows. The value to use will be passed from the EHR.state: This optional parameter is generated by your app and is opaque to the EHR. The EHR's authorization server will append it to each subsequent exchange in the workflow for you to validate session integrity. While not required, this parameter is recommended to be included and validated with each exchange in order to increase security. For more information see RFC 6819 Section 3.6.
state values in combination with launch tokens that are JWTs (see above) may cause the query string for the HTTP GET request to the authorization endpoint to exceed the Epic community member web server's max query string length and cause the request to fail. You can mitigate this risk by: state parameter be an unpredictable value ... with at least 122 bits of entropy (e.g., a properly configured random uuid is suitable), and not store any actual application state in the
state parameter.Additional parameters for native mobile apps (available starting in the August 2019 version of Epic):
code_challenge: This optional parameter is generated by your app and used for PKCE. This is the S256 hashed version of the code_verifier parameter, which will be used in the token request.code_challenge_method: This optional parameter indicates the method used for the code_challenge parameter and is required if using that parameter. Currently, only the S256 method is supported.Here's an example of an authorization request using HTTP GET. You will replace the [redirect_uri], [client_id], [launch_token], [state], and [code_challenge] placeholders with your own values.
https://fhir.epic.com/interconnect-fhir-oauth/oauth2/authorize?scope=launch&response_type=code&redirect_uri=[redirect_uri]&client_id=[client_id]&launch=[launch_token]&state=[state]&code_challenge=[code_challenge]&code_challenge_method=S256This is an example from the SMART on FHIR launchpad:
https://fhir.epic.com/interconnect-fhir-oauth/oauth2/authorize?scope=launch&response_type=code&redirect_uri=https%3A%2F%2Ffhir.epic.com%2Ftest%2Fsmart&client_id=d45049c3-3441-40ef-ab4d-b9cd86a17225&launch=GwWCqm4CCTxJaqJiROISsEsOqN7xrdixqTl2uWZhYxMAS7QbFEbtKgi7AN96fKc2kDYfaFrLi8LQivMkD0BY-942hYgGO0_6DfewP2iwH_pe6tR_-fRfiJ2WB_-1uwG0&state=abc123The EHR's authorization server reviews the request from your application. If approved, the authorization server redirects the browser to the redirect URL supplied in the initial request and appends the following querystring parameter.
code: This parameter contains the authorization code generated by Epic, which will be exchanged for the access token in the next step.
state: This parameter will have the same value as the earlier state parameter. For more information, refer to Step 3.
Here's an example of what the redirect will look like if Epic's authorization server accepts the request:
https://fhir.epic.com/test/smart?code=yfNg-rSc1t5O2p6jVAZLyY00uOOte5KM1y3YUxqsJQnBKEMNsYqOPTyVqcCH3YXaPkLztO9Rvf7bhLqQTwALHcHN6raxpTbR1eVgV2QyLA_4K0HrJO92et3qRXiXPkj7&state=abc123After receiving the authorization code, your application trades the code for a JSON object containing an access token and contextual information by sending an HTTP POST to the token endpoint using a Content-Type header with value of "application/x-www-form-urlencoded". For more information, see RFC 6749 section 4.1.3.
The following parameters are required in the POST body:
grant_type: For the EHR launch flow, this should contain the value "authorization_code".
code: This parameter contains the authorization code sent from Epic's authorization server to your application as a querystring parameter on the redirect URI as described above.
redirect_uri: This parameter must contain the same redirect URI that you provided in the initial access request.
client_id: This parameter must contain the application's client ID issued by Epic that you provided in the initial request.
code_verifier: This optional parameter is used to verify against your code_challenge parameter when using PKCE. This parameter is passed as free text and must match the code_challenge parameter used in your authorization request once it is hashed on the server using the code_challenge_method. This parameter is available starting in the August 2019 version of Epic.
Here's an example of what an HTTP POST request for an access token might look like:
POST https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=yfNg-rSc1t5O2p6jVAZLyY00uOOte5KM1y3YUxqsJQnBKEMNsYqOPTyVqcCH3YXaPkLztO9Rvf7bhLqQTwALHcHN6raxpTbR1eVgV2QyLA_4K0HrJO92et3qRXiXPkj7&redirect_uri=https://fhir.epic.com/test/smart&client_id=d45049c3-3441-40ef-ab4d-b9cd86a17225 The authorization server responds to the HTTP POST request with a JSON object that includes an access token. The response contains the following fields:
access_token: This parameter contains the access token issued by Epic to your application and is used in future requests.
token_type: In Epic's OAuth 2.0 implementation, this parameter always includes the value bearer.
expires_in: This parameter contains the number of seconds for which the access token is valid.
scope: This parameter describes the access your application is authorized for.
id_token: Returned only for applications that have requested an openid scope. See below for more info on OpenID Connect id_tokens. This parameter follows the guidelines of the OpenID Connect (OIDC) Core 1.0 specification. It is signed but not encrypted.
patient: This parameter identifies provides the FHIR ID for the patient, if a patient is in context at time of launch.
epic.dstu2.patient: This parameter identifies the DSTU2 FHIR ID for the patient, if a patient is in context at time of launch.
encounter: This parameter identifies the FHIR ID for the patient’s encounter, if in context at time of launch.
location : This parameter identifies the FHIR ID for the patient’s location, if in context at time of launch.
state: This parameter will have the same value as the earlier state parameter. For more information, refer to Step 3.
Note that you can include additional fields in the response if needed based on the integration configuration. For more information, refer to the Launching your app topic. Here's an example of what a JSON object including an access token might look like:
{
"access_token": "Nxfve4q3H9TKs5F5vf6kRYAZqzK7j9LHvrg1Bw7fU_07_FdV9aRzLCI1GxOn20LuO2Ahl5RkRnz-p8u1MeYWqA85T8s4Ce3LcgQqIwsTkI7wezBsMduPw_xkVtLzLU2O",
"token_type": "bearer",
"expires_in": 3240,
"scope": "openid Patient.read Patient.search ",
"id_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6IktleUlEIiwidHlwIjoiSldUIn0.eyJhdWQiOiJDbGllbnRJRCIsImV4cCI6RXhwaXJlc0F0LCJpYXQiOklzc3VlZEF0LCJpc3MiOiJJc3N1ZXJVUkwiLCJzdWIiOiJFbmRVc2VySWRlbnRpZmllciJ9",
"patient": "T1wI5bk8n1YVgvWk9D05BmRV0Pi3ECImNSK8DKyKltsMB",
"state": "abc123",
}
At this point, authorization is complete and the web application can access the protected patient data it requests using FHIR APIs.
Refresh tokens are not typically needed for embedded (SMART on FHIR) launches because users are not required to log in to Epic during the SMART on FHIR launch process, and the access token obtained from the launch process is typically valid for longer than the user needs to use the app.
Consult the Standalone Launch: Access Token Request for Refresh Token Apps for details on how to obtain an access token if your app uses refresh tokens.
Epic started supporting the OpenID Connect id_token in the access token response for apps that request the openid scope since the November 2019 version of Epic.
A decoded OpenID Connect id_token JWT will have these headers:
| Header | Description |
|---|---|
alg |
The JWT authentication algorithm. Currently only RSA 256 is supported in id_token JWTs so this will always be RS256. |
typ |
This is always set to JWT. |
kid |
The base64 encoded SHA-256 hash of the public key. |
A decoded OpenID Connect id_token JWT will have this payload:
| Claim | Description | Remarks |
|---|---|---|
iss |
Issuer of the JWT. This is set to the token endpoint that should be used by the client. | Starting in the May 2020 version of Epic, the iss will be set to the OAuth 2.0 server endpoint, e.g. https://<Interconnect Server URL>/oauth2. For Epic versions prior to May 2020, it is set to the OAuth 2.0 token endpoint, e.g. https://<Interconnect Server URL>/oauth2/token. |
sub |
STU3+ FHIR ID for the resource representing the user launching the app. | For Epic integrations, the sub and fhirUser claims reference one of the following resources depending on the type of workflow:
|
fhirUser |
Absolute reference to the FHIR resource representing the user launching the app. See the HL7 documentation for more details. | The fhirUser claim will only be present if app has the R4 (or greater) SMART on FHIR version selected, and requests both the openid and fhirUser scopes in the request to the authorize endpoint. See the remark for the sub claim above for more information about what the resource returned in these claims represents. |
aud |
Audiences that the ID token is intended for. This will be set to the client ID for the application that was just authorized during the SMART on FHIR launch. | |
iat |
Time integer for when the JWT was created, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC). | |
exp |
Expiration time integer for this authentication JWT, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC). | This is set to the current time plus 5 minutes. |
Here is an example decoded id_token that could be returned if the app has the R4 (or greater) SMART on FHIR version selected, and requests both the openid and fhirUser scopes in the request to the authorize endpoint:
{
"alg": "RS256",
"kid": "liCulTIaitUzjfUh2AqNiMro47X9HcVcd9XPi8LDJKA=",
"typ": "JWT"
}
{
"aud": "de5dae1a-4317-4c25-86f1-ed558e85529b",
"exp": 1595956317,
"fhirUser": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2/api/FHIR/R4/Practitioner/exfo6E4EXjWsnhA1OGVElgw3",
"iat": 1595956017,
"iss": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2",
"sub": "exfo6E4EXjWsnhA1OGVElgw3"
}
Here is an example decoded id_token that could be returned if the app requests at least the openid scope in the request to the authorize endpoint, but either doesn't request the fhirUser claim or doesn't meet the criteria outlined above for receiving the fhirUser claim:
{
"alg": "RS256",
"kid": "liCulTIaitUzjfUh2AqNiMro47X9HcVcd9XPi8LDJKA=",
"typ": "JWT"
}
{
"aud": "de5dae1a-4317-4c25-86f1-ed558e85529b",
"exp": 1595956317,
"iat": 1595956017,
"iss": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2",
"sub": "exfo6E4EXjWsnhA1OGVElgw3"
}
When completing the OAuth 2.0 authorization workflow with the openid scope, the JSON Web Token (JWT) returned in the id_token field will be cryptographically signed. The public key to verify the authenticity of the JWT can be found at https://<Interconnect Server URL>/api/epic/2019/Security/Open/PublicKeys/530005/OIDC, for example https://fhir.epic.com/interconnect-fhir-oauth/api/epic/2019/Security/Open/PublicKeys/530005/OIDC.
Starting in the May 2020 version of Epic, metadata about the server's OpenID Connect configuration, including the jwks_uri OIDC public key endpoint, can be found at the OpenID configuration endpoint https://<Interconnect Server URL>/oauth2/.well-known/openid-configuration, for example https://fhir.epic.com/interconnect-fhir-oauth/oauth2/.well-known/openid-configuration.
With a valid access token, your application can now access protected patient data from the EHR database using FHIR APIs. Queries must contain an Authorization header that includes the access token presented as a Bearer token.
Here's an example of what a valid query looks like:
GET https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient/T1wI5bk8n1YVgvWk9D05BmRV0Pi3ECImNSK8DKyKltsMB HTTP/1.1
Authorization: Bearer Nxfve4q3H9TKs5F5vf6kRYAZqzK7j9LHvrg1Bw7fU_07_FdV9aRzLCI1GxOn20LuO2Ahl5RkRnz-p8u1MeYWqA85T8s4Ce3LcgQqIwsTkI7wezBsMduPw_xkVtLzLU2ORefresh tokens are not typically needed for embedded (SMART on FHIR) launches because users are not required to log in to Epic during the SMART on FHIR launch process, and the access token obtained from the launch process is typically valid for longer than the user needs to use the app.
Consult the Standalone Launch: Use a Refresh Token to Obtain a New Access Token for details on how to use a refresh token to get a new an access token if your app uses refresh tokens.
Contents
Your application would like to authenticate the user using the OAuth 2.0 workflow. To initiate this process, your app needs to link (using HTTP GET) to the authorize endpoint and append the following querystring parameters, or, in Epic version November 2020 or later, make an HTTP POST request to the authorize endpoint that includes the following parameters in the body of the request.
response_type: This parameter must contain the value "code".client_id: This parameter contains your web application's client ID issued by Epic. redirect_uri: This parameter contains your application's redirect URI. After the request completes on the Epic server, this URI will be called as a callback. The value of this parameter needs to be URL encoded. This URI must also be registered with the EHR's authorization server by adding it to your app listing.state: This optional parameter is generated by your app and is opaque to the EHR. The EHR's authorization server will append it to each subsequent exchange in the workflow for you to validate session integrity. While not required, this parameter is recommended to be included and validated with each exchange in order to increase security. For more information see RFC 6819 Section 3.6.scope: This parameter describes the information for which the web application is requesting access. Starting with the Epic 2018 version, a scope of "launch" is required for EHR launch workflows. Starting with the November 2019 version of Epic, the "openid" and "fhirUser" OpenID Connect scopes are supported.Additional parameters for native mobile apps (available starting in the August 2019 version of Epic):
code_challenge: This optional parameter is generated by your app and used for PKCE. This is the S256 hashed version of the code_verifier parameter, which will be used in the token request.code_challenge_method: This optional parameter indicates the method used for the code_challenge parameter and is required if using that parameter. Currently, only the S256 method is supported.Here's an example of an authorization request using HTTP GET. You will replace the [redirect_uri], [client_id], and [state] placeholders with your own values.
https://fhir.epic.com/interconnect-fhir-oauth/oauth2/authorize?response_type=code&redirect_uri=[redirect_uri]&client_id=[client_id]&state=[state]This is an example link:
https://fhir.epic.com/interconnect-fhir-oauth/oauth2/authorize?response_type=code&redirect_uri=https%3A%2F%2Ffhir.epic.com%2Ftest%2Fsmart&client_id=d45049c3-3441-40ef-ab4d-b9cd86a17225&state=abc123The EHR's authorization server reviews the request from your application, authenticates the user (sample credentials found here), and authorizes access If approved, the authorization server redirects the browser to the redirect URL supplied in the initial request and appends the following querystring parameter.
code: This parameter contains the authorization code generated by Epic, which will be exchanged for the access token in the next step.state: This parameter will have the same value as the earlier state parameter. For more information, refer to Step 1.Here's an example of what the redirect will look like if Epic's authorization server accepts the request:
https://fhir.epic.com/test/smart?code=yfNg-rSc1t5O2p6jVAZLyY00uOOte5KM1y3YUxqsJQnBKEMNsYqOPTyVqcCH3YXaPkLztO9Rvf7bhLqQTwALHcHN6raxpTbR1eVgV2QyLA_4K0HrJO92et3qRXiXPkj7&state=abc123After receiving the authorization code, your application trades the code for a JSON object containing an access token and contextual information by sending an HTTP POST to the token endpoint using a Content-Type header with value of "application/x-www-form-urlencoded". For more information, see RFC 6749 section 4.1.3.
The following parameters are required in the POST body:
grant_type: For the EHR launch flow, this should contain the value "authorization_code".code: This parameter contains the authorization code sent from Epic's authorization server to your application as a querystring parameter on the redirect URI as described above.redirect_uri: This parameter must contain the same redirect URI that you provided in the initial access request.client_id: This parameter must contain the application's client ID issued by Epic that you provided in the initial request.Here's an example of what an HTTP POST request for an access token might look like:
POST https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=yfNg-rSc1t5O2p6jVAZLyY00uOOte5KM1y3YUxqsJQnBKEMNsYqOPTyVqcCH3YXaPkLztO9Rvf7bhLqQTwALHcHN6raxpTbR1eVgV2QyLA_4K0HrJO92et3qRXiXPkj7&redirect_uri=https://fhir.epic.com/test/smart&client_id=d45049c3-3441-40ef-ab4d-b9cd86a17225
The authorization server responds to the HTTP POST request with a JSON object that includes an access token. The response contains the following fields:
access_token: This parameter contains the access token issued by Epic to your application and is used in future requests.token_type: In Epic's OAuth 2.0 implementation, this parameter always includes the value bearer.expires_in: This parameter contains the number of seconds for which the access token is valid.scope: This parameter describes the access your application is authorized for.id_token: Returned only for applications that have requested an openid scope. See above for more info on OpenID Connect id_tokens. This parameter follows the guidelines described earlier in this document.patient: For patient-facing workflows, this parameter identifies the FHIR ID for the patient on whose behalf authorization to the system was granted. epic.dstu2.patient: For patient-facing workflows, this parameter identifies the DSTU2 FHIR ID for the patient on whose behalf authorization to the system was granted. Note that you can pass additional parameters if needed based on the integration configuration. Here's an example of what a JSON object including an access token might look like:
{
"access_token": "Nxfve4q3H9TKs5F5vf6kRYAZqzK7j9LHvrg1Bw7fU_07_FdV9aRzLCI1GxOn20LuO2Ahl5RkRnz-p8u1MeYWqA85T8s4Ce3LcgQqIwsTkI7wezBsMduPw_xkVtLzLU2O",
"token_type": "bearer",
"expires_in": 3240,
"scope": "Patient.read Patient.search ",
"patient": "T1wI5bk8n1YVgvWk9D05BmRV0Pi3ECImNSK8DKyKltsMB"
}At this point, authorization is complete and the web application can access the protected patient data it requested using FHIR APIs.
After receiving the authorization code, your application trades the code for a JSON object containing an access token and contextual information by sending an HTTP POST to the token endpoint using a Content-Type header with value of "application/x-www-form-urlencoded". For more information, see RFC 6749 section 4.1.3.
The Epic on FHIR website can generate a client secret (effectively a password) for your app to use to obtain refresh tokens, and store the hashed secret for you, or Epic community members can upload a client secret hash that you provide them when they activate your app for their system. If you provide community members a client secret hash to upload, you should use a unique client secret per Epic community member and per environment type (non-production and production) for each Epic community member.
The following parameters are required in the POST body:
grant_type: This should contain the value authorization_code.code: This parameter contains the authorization code sent from Epic's authorization server to your application as a querystring parameter on the redirect URI as described above.redirect_uri: This parameter must contain the same redirect URI that you provided in the initial access request.
Note: The client_id parameter is not passed in the the POST body if you use client secret authentication, which is different from the access token request for apps that do not use refresh tokens. You will instead pass an Authorization HTTP header with client_id and client_secret URL encoded and passed as a username and password. Conceptually the Authorization HTTP header will have this value: base64(client_id:client_secret).
For example, using the following client_id and client_secret:
client_id: d45049c3-3441-40ef-ab4d-b9cd86a17225
URL encoded client_id: d45049c3-3441-40ef-ab4d-b9cd86a17225 Note: base64 encoding Epic's client IDs will have no effect
client_secret: this-is-the-secret-2/7
URL encoded client_secret: this-is-the-secret-2%2F7
Would result in this Authorization header:
Authorization: Basic base64Encode{d45049c3-3441-40ef-ab4d-b9cd86a17225:this-is-the-secret-2%2F7}or
Authorization: Basic ZDQ1MDQ5YzMtMzQ0MS00MGVmLWFiNGQtYjljZDg2YTE3MjI1OnRoaXMtaXMtdGhlLXNlY3JldC0yJTJGNw==Here's an example of what a valid HTTP POST might look like:
POST https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: Basic ZDQ1MDQ5YzMtMzQ0MS00MGVmLWFiNGQtYjljZDg2YTE3MjI1OnRoaXMtaXMtdGhlLXNlY3JldC0yJTJGNw==
grant_type=authorization_code&code=yfNg-rSc1t5O2p6jVAZLyY00uOOte5KM1y3YUxqsJQnBKEMNsYqOPTyVqcCH3YXaPkLztO9Rvf7bhLqQTwALHcHN6raxpTbR1eVgV2QyLA_4K0HrJO92et3qRXiXPkj7&redirect_uri=https://fhir.epic.com/test/smartThe authorization server responds to the HTTP POST request with a JSON object that includes an access token and a refresh token. The response contains the following fields:
refresh_token: This parameter contains the refresh token issued by Epic to your application and can be used to obtain a new access token. For more information on how this works, see Step 5.access_token: This parameter contains the access token issued by Epic to your application and is used in future requests.token_type: In Epic's OAuth 2.0 implementation, this parameter always includes the value bearer.expires_in: This parameter contains the number of seconds for which the access token is valid.scope: This parameter describes the access your application is authorized for.id_token: Returned only for applications that have requested an openid scope. See above for more info on OpenID Connect id_tokens. This parameter follows the guidelines of the OpenID Connect (OIDC) Core 1.0 specification. It is signed but not encrypted.
patient: For patient-facing workflows, this parameter identifies the FHIR ID for the patient on whose behalf authorization to the system was granted. epic.dstu2.patient: For patient-facing workflows, this parameter identifies the DSTU2 FHIR ID for the patient on whose behalf authorization to the system was granted. encounter: This parameter identifies the FHIR ID for the patient’s encounter, if in context at time of launch. location: This parameter identifies the FHIR ID for the patient’s location, if in context at time of launch. Note that you can pass additional parameters if needed based on the integration configuration. Here's an example of what a JSON object including an access token and refres token might look like:
{
"access_token": "Nxfve4q3H9TKs5F5vf6kRYAZqzK7j9LHvrg1Bw7fU_07_FdV9aRzLCI1GxOn20LuO2Ahl5RkRnz-p8u1MeYWqA85T8s4Ce3LcgQqIwsTkI7wezBsMduPw_xkVtLzLU2O",
"refresh_token": "H9TKs5F5vf6kRYAZqzK7j9L_07_FdV9aRzLCI1GxOn20LuO2Ahl5R1MeYWqA85T8s4sTkI7wezBsMduPw_xkLzLU2O",
"token_type": "bearer",
"expires_in": 3240,
"scope": "Patient.read Patient.search ",
"patient": "T1wI5bk8n1YVgvWk9D05BmRV0Pi3ECImNSK8DKyKltsMB"
}At this point, authorization is complete and the web application can access the protected patient data it requested using FHIR APIs.
With a valid access token, your application can now access protected patient data from the EHR database using FHIR APIs. Queries must contain an Authorization header that includes the access token presented as a Bearer token.
Here's an example of what a valid query looks like:
GET https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient/T1wI5bk8n1YVgvWk9D05BmRV0Pi3ECImNSK8DKyKltsMB HTTP/1.1
Authorization: Bearer Nxfve4q3H9TKs5F5vf6kRYAZqzK7j9LHvrg1Bw7fU_07_FdV9aRzLCI1GxOn20LuO2Ahl5RkRnz-p8u1MeYWqA85T8s4Ce3LcgQqIwsTkI7wezBsMduPw_xkVtLzLU2OIf your app uses refresh tokens (i.e. it can securely store credentials), then you can use a refresh token to request a new access token when the current access token expires (determined by the expires_in field from the authorization response from step 3).
Your application trades the refresh_token for a JSON object containing a new access token, (optionally) a new refresh token, and contextual information by sending an HTTP POST to the token endpoint using a Content-Type HTTP header with value of "application/x-www-form-urlencoded". For more information, see RFC 6749 section 4.1.3.
The Epic on FHIR website can generate a client secret (effectively a password) for your app when using refresh tokens, and store the hashed secret for you, or Epic community members can upload a client secret hash that you provide them when they activate your app for their system. If you provide community members a client secret hash to upload, you should use a unique client secret per Epic community member and per environment type (non-production and production) for each Epic community member.
The following parameters are required in the POST body:
grant_type: This parameter always contains the value refresh_token.refresh_token: The refresh token received from a prior authorization request.
An Authorization header using HTTP Basic Authentication is required, where the username is the URL encoded client_id and the password is the URL encoded client_secret.
For example, using the following client_id and client_secret:
client_id: d45049c3-3441-40ef-ab4d-b9cd86a17225
URL encoded client_id: d45049c3-3441-40ef-ab4d-b9cd86a17225 Note: base64 encoding Epic's client IDs will have no effect
client_secret: this-is-the-secret-2/7
URL encoded client_secret: this-is-the-secret-2%2F7
Would result in this Authorization header:
Authorization: Basic base64Encode{d45049c3-3441-40ef-ab4d-b9cd86a17225:this-is-the-secret-2%2F7}or
Authorization: Basic ZDQ1MDQ5YzMtMzQ0MS00MGVmLWFiNGQtYjljZDg2YTE3MjI1OnRoaXMtaXMtdGhlLXNlY3JldC0yJTJGNw==Here's an example of what a valid HTTP POST might look like:
POST https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token HTTP/1.1
Authorization: Basic ZDQ1MDQ5YzMtMzQ0MS00MGVmLWFiNGQtYjljZDg2YTE3MjI1OnRoaXMtaXMtdGhlLXNlY3JldC0yJTJGNw==
Content-Type: application/x-www-form-urlencoded
grant_type=refresh_token&refresh_token=j12xcniournlsdf234bgsdThe authorization server responds to the HTTP POST request with a JSON object that includes the new access token, and optionally a new refresh token. The response contains the following fields:
access_token: This parameter contains the new access token issued.token_type: In Epic's OAuth 2.0 implementation, this parameter always includes the value bearer.expires_in: This parameter contains the number of seconds for which the access token is valid.scope: This parameter describes the access your application is authorized for.refresh_token: (Optional) New refresh token issued, which replaces the previous one.An example response to the previous request may look like the following:
{
"access_token": "57CjhZEdiTcCh1nqIwQUw5rODOLP3bSTnMEGNYbBerSeNn8hIUm6Mlc5ruCTfQawjRAoR8sYr8S_7vNdnJfgRKfD6s8mOqPnvJ8vZOHjEvy7l3Ra9frDaEAUBbN-j86k",
"token_type": "bearer",
"expires_in": 3240,
"scope": "Patient.read Patient.search ",
"refresh_token": "b72foiua9asdhnkjanvm"
}Contents
Backend apps (i.e. apps without direct end user or patient interaction) can also use OAuth 2.0 authentication through the client_credentials OAuth 2.0 grant type. Epic's OAuth 2.0 implementation for backend services follows the SMART Backend Services: Authorization Guide, though it currently differs from that profile in some respects. Application vendors pre-register a public key for a given Epic community member on the Epic on FHIR website and then use the corresponding private key to sign a JSON Web Token (JWT) which is presented to the authorization server to obtain an access token.
To use the client_credentials OAuth 2.0 grant type to authorize your backend application's access to patient information, two pieces of information need to be shared between the authorization server and your application:
You can register your application for access to both the sandbox and Epic organizations here. You'll provide information to us, including a public key used to verify the JWT signature, and Epic will generate a client ID for you. Your app will need to have the Backend Systems radio button selected in order to register a public key for backend OAuth 2.0.
An Epic community member's Epic Client Systems Administrator (ECSA) will need to map your client ID to an Epic user account that will be used for auditing web service calls made by your backend application. Your app will not be able to obtain an access token until this build is completed.
Note: This build is not needed in the sandbox. The sandbox automatically maps your client to a default user, removing the need for this setup.
There are several tools you can use to create a key pair. As long as you can export your public key to a base64 encoded X.509 certificate for registration on the Epic on FHIR website, the tool you use to create the key pair and file format used to store the keys is not important. If your app is hosted by Epic community members ("on prem" hosting) instead of cloud hosted you should have unique key pairs for each Epic community member you integrate with. In addition, you should always use unique key pairs for non-production and production systems.
Here are examples of two tools commonly used to generate key pairs:
You can create a new private key named privatekey.pem using OpenSSL with the following command:
openssl genrsa -out /path_to_key/privatekey.pem 2048
Make sure the key length is at least 2048 bits.
Then you can export the public key to a base64 encoded X.509 certificate named publickey509.pem using this command:
openssl req -new -x509 -key /path_to_key/privatekey.pem -out /path_to_key/publickey509.pem -subj '/CN=myapp'
Where '/CN=myapp' is the subject name (for example the app name) the key pair is for. The subject name does not have a functional impact in this case but it is required for creating an X.509 certificate.
You can create a key pair using Windows PowerShell with this command, making sure to run PowerShell as an administrator:
New-SelfSignedCertificate -Subject "MyApp"
Note that the Epic on FHIR website is extracting the public key from the certificate and discarding the rest of the certificate information, so it's not 'trusting' the self-signed certificate per se.
The subject name does not have a functional impact in this case but it is required for creating an X.509 certificate.
You can export the public key using either PowerShell or Microsoft Management Console.
If you want to export the public key using PowerShell, take note of the certificate thumbprint and storage location printed when you executed the New-SelfSignedCertificate command.
PS C:\dir> New-SelfSignedCertificate -Subject "MyApp"
PSParentPath: Microsoft.PowerShell.Security\Certificate::LocalMachine\MY
Thumbprint Subject
---------- -------
3C4A558635D67F631E5E4BFDF28AE59B2E4421BA CN=MyAppThen export the public key to a X.509 certificate using the following commands (using the thumbprint and certificate location from the above example):
PS C:\dir> $cert = Get-ChildItem -Path Cert:\LocalMachine\My\3C4A558635D67F631E5E4BFDF28AE59B2E4421BA
PS C:\dir> Export-Certificate -Cert $cert -FilePath newpubkeypowerShell.cer
Export the binary certificate to a base64 encoded certificate:
PS C:\dir> certutil.exe -encode newpubkeypowerShell.cer newpubkeybase64.cer
If you want to export the public key using Microsoft Management Console, follow these steps:
New-SelfSignedCertificate PowerShell command above. The store used is displayed in the printout after the command completes.
-Subject during key creation (e.g. "MyApp" above).
The public key certificate fingerprint (also known as thumbprint in Windows software) is displayed for JWT signing public key certificates that are uploaded to the Epic on FHIR website. There are a few ways you can find the fingerprint for a public key certificate:
Get-ChildItem PowerShell command. For example, run Get-ChildItem -Path Cert:\LocalMachine\My to find all certificate thumbprints in the local machine storage.
$ openssl x509 -noout -fingerprint -sha1 -inform pem -in openssl_publickey.cert
Note that the output from this command includes colons between bytes which are not shown on the Epic on FHIR website.
You will generate a one-time use JSON Web Token (JWT) to authenticate your app to the authorization server and obtain an access token that can be used to authenticate your app's web service calls. There are several libraries for creating JWTs. See jwt.io for some examples.
The JWT should have these headers:
| Header | Description |
|---|---|
alg |
The JWT authentication algorithm. Currently only RSA signing algorithms are supported so RSA 384 should be used and this should be set to RS384. |
typ |
This should always be set to JWT. |
The JWT header should be formatted as follows:
{
"alg": "RS384",
"typ": "JWT"
}The JWT should have these claims in the payload:
| Claim | Description | Remarks |
|---|---|---|
iss |
Issuer of the JWT. This is the app's client_id, as determined during registration on the Epic on FHIR website.
|
This is the same as the value for the sub claim. |
sub |
The service's client_id, as determined during registration on the Epic on FHIR website.
|
This is the same as the value for the iss claim. |
aud |
The FHIR authorization server's token endpoint URL. This is the same URL to which this authentication JWT will be posted. See below for an example POST. | It's possible that Epic community member systems will route web service traffic through a proxy server, in which case the URL the JWT is posted to is not known to the authorization server, and the JWT will be rejected. For such cases, Epic community member administrators can add additional audience URLs to the allowlist, in addition to the FHIR server token URL if needed. |
jti |
A unique identifier for the JWT. | The jti must be no longer than 151 characters and cannot be reused during the JWT's validity period, i.e. before the exp time is reached. |
exp |
Expiration time integer for this authentication JWT, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC). | The exp value must be in the future, and can be no more than 5 minutes in the future at the time the access token request is received. |
nbf |
Time integer before which the JWT must not be accepted for processing, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC). | The nbf value cannot be in the future, cannot be more recent than the exp value, and the exp - nbf difference cannot be greater than 5 minutes. |
iat |
Time integer for when the JWT was created, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC). | The iat value cannot be in the future, and the exp - iat difference cannot be greater than 5 minutes. |
Here's an example JWT payload:
{
"iss": "d45049c3-3441-40ef-ab4d-b9cd86a17225",
"sub": "d45049c3-3441-40ef-ab4d-b9cd86a17225",
"aud": "https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token",
"jti": "f9eaafba-2e49-11ea-8880-5ce0c5aee679",
"exp": 1583524402,
"nbf": 1583524102,
"iat": 1583524102
}The header and payload are then base64 URL encoded, combined with a period separating them, and cryptographically signed using the private key to generate a signature. Conceptually:
signature = RSA-SHA384(base64urlEncoding(header) + '.' + base64urlEncoding(payload), privatekey)The full JWT is constructed by combining the header, body and signature as follows:
base64urlEncoding(header) + '.' + base64urlEncoding(payload) + '.' + base64urlEncoding(signature)A fully constructed JWT looks something like this:
eyJhbGciOiJSUzM4NCIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkNDUwNDljMy0zNDQxLTQwZWYtYWI0ZC1iOWNkODZhMTcyMjUiLCJzdWIiOiJkNDUwNDljMy0zNDQxLTQwZWYtYWI0ZC1iOWNkODZhMTcyMjUiLCJhdWQiOiJodHRwczovL2ZoaXIuZXBpYy5jb20vaW50ZXJjb25uZWN0LWZoaXItb2F1dGgvb2F1dGgyL3Rva2VuIiwianRpIjoiZjllYWFmYmEtMmU0OS0xMWVhLTg4ODAtNWNlMGM1YWVlNjc5IiwiZXhwIjoxNTgzNTI0NDAyLCJuYmYiOjE1ODM1MjQxMDIsImlhdCI6MTU4MzUyNDEwMn0.dztrzHo9RRwNRaB32QxYLaa9CcIMoOePRCbpqsRKgyJmBOGb9acnEZARaCzRDGQrXccAQ9-syuxz5QRMHda0S3VbqM2KX0VRh9GfqG3WJBizp11Lzvc2qiUPr9i9CqjtqiwAbkME40tioIJMC6DKvxxjuS-St5pZbSHR-kjn3ex2iwUJgPbCfv8cJmt19dHctixFR6OG-YB6lFXXpNP8XnL7g85yLOYoQcwofN0k8qK8h4uh8axTPC21fv21mCt50gx59XgKsszysZnMDt8OG_G4gjk_8JnGHwOVkJhqj5oeg_GdmBhQ4UPuxt3YvCOTW9S2vMikNUnxrhdVvn2GVgYour application makes a HTTP POST request to the authorization server's OAuth 2.0 token endpoint to obtain access token. The following form-urlencoded parameters are required in the POST body:
grant_type: This should be set to client_credentials.client_assertion_type: This should be set to urn:ietf:params:oauth:client-assertion-type:jwt-bearer.client_assertion: This should be set to the JWT you created above.Here is an example request:
POST https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
grant_type=client_credentials&client_assertion_type=urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer&client_assertion=eyJhbGciOiJSUzM4NCIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJkNDUwNDljMy0zNDQxLTQwZWYtYWI0ZC1iOWNkODZhMTcyMjUiLCJzdWIiOiJkNDUwNDljMy0zNDQxLTQwZWYtYWI0ZC1iOWNkODZhMTcyMjUiLCJhdWQiOiJodHRwczovL2ZoaXIuZXBpYy5jb20vaW50ZXJjb25uZWN0LWZoaXItb2F1dGgvb2F1dGgyL3Rva2VuIiwianRpIjoiZjllYWFmYmEtMmU0OS0xMWVhLTg4ODAtNWNlMGM1YWVlNjc5IiwiZXhwIjoxNTgzNTI0NDAyLCJuYmYiOjE1ODM1MjQxMDIsImlhdCI6MTU4MzUyNDEwMn0.dztrzHo9RRwNRaB32QxYLaa9CcIMoOePRCbpqsRKgyJmBOGb9acnEZARaCzRDGQrXccAQ9-syuxz5QRMHda0S3VbqM2KX0VRh9GfqG3WJBizp11Lzvc2qiUPr9i9CqjtqiwAbkME40tioIJMC6DKvxxjuS-St5pZbSHR-kjn3ex2iwUJgPbCfv8cJmt19dHctixFR6OG-YB6lFXXpNP8XnL7g85yLOYoQcwofN0k8qK8h4uh8axTPC21fv21mCt50gx59XgKsszysZnMDt8OG_G4gjk_8JnGHwOVkJhqj5oeg_GdmBhQ4UPuxt3YvCOTW9S2vMikNUnxrhdVvn2GVgAnd here is an example response body assuming the authorization server approves the request:
{
"access_token": "i82fGhXNxmidCt0OdjYttm2x0cOKU1ZbN6Y_-zBvt2kw3xn-MY3gY4lOXPee6iKPw3JncYBT1Y-kdPpBYl-lsmUlA4x5dUVC1qbjEi1OHfe_Oa-VRUAeabnMLjYgKI7b",
"token_type": "bearer",
"expires_in": 3600,
"scope": "Patient.read Patient.search"
}HTTP Basic Authentication requires that Epic community members provision a username and password that your application will provide to the web server to authenticate every request.
Epic supports HTTP Basic Authentication via a system-level user record created within Epic's database. You may hear this referred to as an EMP record. You will need to work with an organization's Epic user security team to have a username and password provided to you.
When calling Epic's web services with HTTP Basic Authentication the username must be provided as follows: emp$<username>. Replace <username> with the username provided by the organization during implementation of your application.
Base64 encode your application's credentials and pass them in the HTTP Authorization header. For example, if you've been given a system-level username/password combination that is username/Pa$$w0rd1, the Authorization header would have a value of ZW1wJHVzZXJuYW1lOlBhJCR3MHJkMQ== (the base64 encoded version of emp$username:Pa$$w0rd1):
GET http://localhost:8888/website HTTP/1.1
Host: localhost:8888
Proxy-Connection: keep-alive
Authorization: Basic ZW1wJHVzZXJuYW1lOlBhJCR3MHJkMQ==The username and password you use to authenticate your web service requests are extremely sensitive since they can be used to pull PHI out of an Epic organization's system. The credentials should always be encrypted and should not be stored directly within your client's code. You should make sure that access to decrypt the credentials should be limited to only the users that need access to it. For example, if a service account submits the web service requests, only that service account should be able to decrypt the credentials.
Epic also supports the use of Client Certificates and SAML tokens as an authentication mechanism for server-to-server web service requests. We do not prefer these methods because both require web server administrators to maintain a trusted certificate for authentication. As certificates expire or servers need to be moved around, this puts an additional burden on system administrators.
When you use OAuth 2.0 authentication, Epic can automatically gather important information about the client making a web service request. When you use a non-OAuth 2.0 authentication mechanism, we require that this additional information be passed in an HTTP header.
This is the client ID you were given upon your app's creation on the Epic on FHIR site. This is always required when calling Epic's web services if your app doesn't use OAuth 2.0 authentication.
GET http://localhost:8888/website HTTP/1.1
Host: localhost:8888
Proxy-Connection: keep-alive
Authorization: Basic ZW1wJHVzZXJuYW1lOlBhJCR3MHJkMQ==
Epic-Client-ID: 0000-0000-0000-0000-0000This is required for auditing requests to FHIR resources. The Epic-User-ID corresponds to an EMP (Epic User) account that an organization creates for your application. This might be required depending on the web services you are calling. The Epic-User-IDType is almost always EXTERNAL.
GET http://localhost:8888/website HTTP/1.1
Host: localhost:8888
Proxy-Connection: keep-alive
Authorization: Basic ZW1wJHVzZXJuYW1lOlBhJCR3MHJkMQ==
Epic-Client-ID: 0000-0000-0000-0000-0000
Epic-User-ID: username
Epic-User-IDType: EXTERNALFHIR is all about quickly getting data about a patient from a clinical system, and FHIR is all interconnected — you can build on top of your queries to get a wide variety of data. The topics below include a walkthrough introduction to FHIR data and sample patient and clinical information - everything you need to turn up the heat on your first FHIR App!
Let's walk through a couple of examples using jQuery — in a larger application, you might build your own framework, or use an existing one, to interact with FHIR, but FHIR is easy enough to use without any special libraries. This tutorial assumes you are passing a form of authorization covered in one of our authentication guides. It's important to note FHIR APIs support OAuth 2.0 and additionally HTTP Basic Authentication.
To get started, let's define the FHIR server base URL. This is a constant address that all FHIR API endpoints for the server's default FHIR version live under. In a SMART on FHIR launch, this is specified with the iss parameter. We'll store this variable as a separate entity, so we can reference it across our queries:
var baseUrl = "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2"
You can expect the bold part of the above URL to be different for each unique instance of Epic you integrate with.
With the base URL defined, we can start building some simple queries and investigating the API. Because we're interacting with patient data, there's an obvious place to get started: finding the patient whose data we want to show. Epic's FHIR support provides two methods for applications to find and interact with patients:
var patientSearchString = "/Patient?given=Derrick&family=Lin&birthdate=1973-06-03"
We can use jQuery's $.getJSON() function to call into the URL and retrieve our data in JSON format. It takes a parameter describing the URL to query, and a callback for doing something with the data once the API responds. In our case, let's just log the data to the console so we can inspect it before developing code that works with it:
$.getJSON(baseUrl + patientSearchString, function(data,error) { console.log(data); });
The complete request URL at this point will read:
"https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient?family=Lin&given=Derrick&birthdate=1973-06-03"
If you execute the above request, you'll be able to see the following response in your console:
{
"resourceType": "Bundle",
"type": "searchset",
"total": 1,
"link": [
{
"relation": "self",
"url": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient?family=Lin&given=Derrick&birthdate=1973-06-03"
}
],
"entry": [
{
"link": [
{
"relation": "self",
"url": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient/TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB"
}
],
"fullUrl": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient/TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB",
"resource": {
"resourceType": "Patient",
"id": "TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB",
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/us-core-race",
"valueCodeableConcept": {
"coding": [
{
"system": "urn:oid:2.16.840.1.113883.5.104",
"code": "2028-9",
"display": "Asian"
}
],
"text": "Asian"
}
},
{
"url": "http://hl7.org/fhir/StructureDefinition/us-core-ethnicity",
"valueCodeableConcept": {
"coding": [
{
"system": "urn:oid:2.16.840.1.113883.5.50",
"code": "UNK",
"display": "Unknown"
}
],
"text": "Unknown"
}
},
{
"url": "http://hl7.org/fhir/StructureDefinition/us-core-birth-sex",
"valueCodeableConcept": {
"coding": [
{
"system": "http://hl7.org/fhir/v3/AdministrativeGender",
"code": "M",
"display": "Male"
}
],
"text": "Male"
}
}
],
"identifier": [
{
"use": "usual",
"system": "urn:oid:1.2.840.114350.1.13.0.1.7.5.737384.0",
"value": "E4005"
},
{
"use": "usual",
"system": "urn:oid:1.2.840.114350.1.13.0.1.7.5.737384.14",
"value": "203711"
},
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/rendered-value",
"valueString": "xxx-xx-0000"
}
],
"use": "usual",
"system": "urn:oid:2.16.840.1.113883.4.1"
}
],
"active": true,
"name": [
{
"use": "usual",
"text": "Derrick Lin",
"family": [
"Lin"
],
"given": [
"Derrick"
]
}
],
"telecom": [
{
"system": "phone",
"value": "785-555-5555",
"use": "home"
},
{
"system": "phone",
"value": "785-666-6666",
"use": "work"
}
],
"gender": "male",
"birthDate": "1973-06-03",
"deceasedBoolean": false,
"address": [
{
"use": "home",
"line": [
"7324 Roosevelt Ave"
],
"city": "INDIANAPOLIS",
"state": "IN",
"postalCode": "46201",
"country": "US",
"period": {
"start": "2019-05-24T00:00:00Z"
}
}
],
"maritalStatus": {
"text": "Married"
},
"communication": [
{
"language": {
"coding": [
{
"system": "urn:oid:2.16.840.1.113883.6.99",
"code": "en",
"display": "English"
}
],
"text": "English"
},
"preferred": true
}
]
},
"search": {
"mode": "match"
}
}
]
}
Let's pick out a couple of key elements to learn more about:
The total element tells us how many elements were found in the search:
total of 0 elements tells us that no results were found in the search. This may mean that you didn't provide enough demographic data to make a match, or that the API doesn't know about the patient you're looking for.total of 1 element tells us that exactly one patient was found. A single patient returned in a search likely means that you've found the right person, but you should always check the demographic information to confirm.total of more than 1 element tells us that the demographic information wasn't sufficient to match to a single patient. If this happens, you can examine the response to match against known demographic data, or perform a second query against the API with additional demographic information.Ideally, you provide enough patient information in your initial search for the API to return a single patient — it's much safer to confirm a single patient than to compare a list of possible results, and it reduces the complexity on your app's users to select a single patient rather than review a list.
In our case, we found exactly one patient, Derrick — exactly the patient we were looking for. If we were building a more complex app, we might need to handle other scenarios gracefully, such as when no patients are found.
The following response is an example of what to expect if a patient match is not found. Note the text contained within the OperationOutcome resource:
{
"resourceType": "Bundle",
"type": "searchset",
"total": 0,
"link": [
{
"relation": "self",
"url": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient?given=Derrick"
}
],
"entry": [
{
"resource": {
"resourceType": "OperationOutcome",
"issue": [
{
"severity": "warning",
"code": "informational",
"details": {
"coding": [
{
"system": "urn:oid:1.2.840.114350.1.13.0.1.7.2.657369",
"code": "4101",
"display": "Resource request returns no results."
}
],
"text": "Resource request returns no results."
}
}
]
},
"search": {
"mode": "outcome"
}
}
]
}
The entry[n].link[n].url element points to the permanent location of a unique patient. If we make a request to this URL, we will always get back that patient's data. Storing this URL can be useful if you want to save off a list of recently used patients, for example. The last part of the url in our search example is Derrick's FHIR ID. We'll use this to make all of our other queries to FHIR APIs.
The entry[0].resource element contains all of the actual data about Derrick Lin. Within this object, you'll find information about Derrick such as his address, phone number, and birth date.
That's a quick overview of the patient search endpoint, but if you're interested in learning more about our Patient search, you can read more here. Let's continue on by saving off Derrick's FHIR ID so we can refer to it later:
var patientId = data.entry[0].link[0].url.split("/").pop();
There are several versions of the FHIR standard. You might use DSTU2 FHIR resources (like in the example above), STU3 resources, or more recent versions of FHIR resources, such as R4 resources. A variety of R4 resources are supported starting in the August 2019 version of Epic.
For R4 and later versions of FHIR, Epic uses relative URLs for all referenced FHIR resources included in a query response. For example, if we look back at the sample response from our Patient query above, if that query was an R4 version Patient query, instead of returning an absolute reference URL for the careProvider:
"careProvider": [
{
"display": "Physician Family Medicine, MD",
"reference": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Practitioner/Thh97FZ9lU9.p-Rgpozo6vwB"
}
]
An R4 resource would return a relative URL instead:
"careProvider": [
{
"display": "Physician Family Medicine, MD",
"reference": "Practitioner/Thh97FZ9lU9.p-Rgpozo6vwB"
}
]
This distinction is important to keep in mind, particularly if you’re working with some FHIR resources that use the DSTU2 or STU3 standard, and other resources that use the R4 standard. Make sure to append the baseURL to the front of the relative URL when querying referenced FHIR resources.
So we've found our patient, and we have some demographics that we could parse and display to an end user. But how do we get access to clinical information about that patient? To retrieve this data, we need to use another endpoint within our API, along with the patient ID we saved off above.
Let's start with a simple query — retrieving a patient's diagnoses. The Condition endpoint exposes exactly that, and provides a search endpoint to find diagnoses by Patient ID. We can construct a query that provides Derrick's FHIR ID to grab all of the active diagnoses recorded in our system:
var conditionSearchString = "/Condition?patient=" + patientId;
We'll use the same method as we did with the Patient search to investigate the response returned from the Condition API, and log the response body to the console as a simple means to view the data.
$.getJSON(baseUrl + conditionSearchString, function(data,error) { console.log(data); });
Executing the above request returns the following:
{
"resourceType": "Bundle",
"type": "searchset",
"total": 1,
"link": [
{
"relation": "self",
"url": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Condition?patient=TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB&category=diagnosis"
}
],
"entry": [
{
"link": [
{
"relation": "self",
"url": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Condition/TH12jkQYrabXcEh-2vXMxLAB"
}
],
"fullUrl": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Condition/TH12jkQYrabXcEh-2vXMxLAB",
"resource": {
"resourceType": "Condition",
"id": "TH12jkQYrabXcEh-2vXMxLAB",
"patient": {
"display": "Derrick Lin",
"reference": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Patient/TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB"
},
"asserter": {
"display": "Physician Family Medicine, MD",
"reference": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/DSTU2/Practitioner/Thh97FZ9lU9.p-Rgpozo6vwB"
},
"dateRecorded": "2019-05-28",
"code": {
"coding": [
{
"system": "http://hl7.org/fhir/sid/icd-9-cm/diagnosis",
"code": "V49.89",
"display": "Risk for coronary artery disease between 10% and 20% in next 10 years"
},
{
"system": "urn:oid:2.16.840.1.113883.6.90",
"code": "Z91.89",
"display": "Risk for coronary artery disease between 10% and 20% in next 10 years"
},
{
"system": "http://snomed.info/sct",
"code": "315016007",
"display": "At risk of coronary heart disease (finding)"
}
],
"text": "Risk for coronary artery disease between 10% and 20% in next 10 years"
},
"category": {
"coding": [
{
"system": "http://loinc.org",
"code": "29308-4",
"display": "Diagnosis"
},
{
"system": "http://snomed.info/sct",
"code": "439401001",
"display": "Diagnosis"
},
{
"system": "http://hl7.org/fhir/condition-category",
"code": "diagnosis",
"display": "Diagnosis"
},
{
"system": "http://argonautwiki.hl7.org/extension-codes",
"code": "problem",
"display": "Problem"
}
],
"text": "Diagnosis"
},
"clinicalStatus": "active",
"verificationStatus": "confirmed",
"onsetDateTime": "2019-05-28"
},
"search": {
"mode": "match"
}
}
]
}
Looking at the response, there are a couple of key elements to highlight to help us understand the condition information:
As with Patient, the total element lets you know the number of diagnoses returned for a query. In this case, it lets us know how many diagnoses our system has documented for Derrick Lin.
The entry[n].link[n].url element points to the permanent location of a unique Condition resource. If we make a request to this URL, we will always get back data for this specific diagnosis for the patient. The last part of the url in our search example is the FHIR ID for this Condition. The FHIR ID for this resource can also be retrieved directly from entry[n].resource[n].id. This might be useful for future reference to check whether the patient has any new conditions documented.
The entry[n].resource[n].patient element describes the patient the diagnosis relates to. This allows us to confirm the association between diagnosis and patient, and shows how FHIR works by linking these smaller resources to paint a larger picture. In this case, the element in each diagnosis entry points to our patient, Derrick.
The entry[n].resource[n].asserter element describes the clinician who recorded the diagnosis in the system. A link to the provider resource is included to allow you to search additional information about the provider who recorded this diagnosis.
The onsetDateTime tells you when the condition was first noticed.
recordedDate element tells you when the diagnosis was actually made and recorded.That's a lot of information with a simple query, and it demonstrates how quickly we can build up and associate the different endpoints available on our API.
Nice work! You made it to the end of our walkthrough, and you understand how to find patients, and start working with their data. There's even more to discover in our documentation, like additional data types, and more complex searches.
In this section we'll cover a few advanced topics that may come up in your implementation of FHIR.
Epic’s FHIR server defaults to using XML for FHIR resources, but many apps may prefer sending and receiving JSON instead. FHIR allows both XML and JSON MIME-types and specifies how a client can request one or the other. Per the FHIR spec and in Epic’s FHIR server, a client can specify XML or JSON through either the _format query parameter or by specifying the MIME-type in an HTTP header. A client should use the Accept HTTP header to specify the MIME-type of the content that it wishes to receive from the server and the Content-Type HTTP header to specify the MIME-type of the content that it is sending in the body of its request, for example, as part of a create or update.
Epic supports all of the following MIME-types for FHIR interactions:
You might come across a FHIR API that you want to use that is only available in STU3, but the base URL for the environment returns a DSTU2 endpoint. This means that you will have a patient's DSTU2 FHIR ID but an STU3 resource requires an STU3 FHIR ID. As of the November 2018 version, Patient FHIR resources are FHIR ID version agnostic and you can use the Patient DSTU2 ID with the Patient STU3 resource and vice versa. As of the May 2019 version, all FHIR resources are Patient FHIR ID version agnostic and you can use the Patient DSTU2 ID with all STU3 resources and vice versa. You can pass in PatientID and PatientIDType to return a collection of different identifiers unique to a patient using the Patient.Read FHIR (STU3) resource. This can be used to get different Patient FHIR version IDs or to get an Epic-specific ID from a FHIR ID or vice versa. To start, we need to construct a search string for this resource.
Using the provided URL template for this web service, we can create a search string. Note, this can be a DSTU2 ID for the STU3 resource in November 2018+:
var baseUrl = "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/STU3"
var identifierSearchString = "/Patient/" + patientId;
We can use jQuery's $.getJSON() function to call into the URL and retrieve our data in JSON format. It takes a parameter describing the URL to query, and a callback for doing something with the data once the API responds. In our case, let's just log the data to the console so we can inspect it before developing code that works with it:
$.getJSON(baseUrl + identifierSearchString, function(data,error) { console.log(data); });
The response contains a number of identifiers for the patient, most notably Derrick's FHIR STU3 ID, in the identifier element:
{
"resourceType": "Patient",
"id": "eq081-VQEgP8drUUqCWzHfw3",
"extension": [
{
"valueCode": "M",
"url": "http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex"
},
{
"extension": [
{
"valueCoding": {
"system": "http://hl7.org/fhir/us/core/ValueSet/omb-race-category",
"code": "2028-9",
"display": "Asian"
},
"url": "ombCategory"
},
{
"valueString": "Asian",
"url": "text"
}
],
"url": "http://hl7.org/fhir/us/core/StructureDefinition/us-core-race"
},
{
"extension": [
{
"valueCoding": {
"system": "http://hl7.org/fhir/us/core/ValueSet/omb-ethnicity-category",
"code": "UNK",
"display": "Unknown"
},
"url": "ombCategory"
},
{
"valueString": "Unknown",
"url": "text"
}
],
"url": "http://hl7.org/fhir/us/core/StructureDefinition/us-core-ethnicity"
}
],
"identifier": [
{
"use": "usual",
"type": {
"text": "EPIC"
},
"system": "urn:oid:1.2.840.114350.1.13.0.1.7.5.737384.0",
"value": "E4005"
},
{
"use": "usual",
"type": {
"text": "EXTERNAL"
},
"value": "Z6127"
},
{
"use": "usual",
"type": {
"text": "FHIR"
},
"value": "TGsj9rYGI8SV-LYYkdH1JqbxYuFGfrODXSPC6iLLYkJcB"
},
{
"use": "usual",
"type": {
"text": "FHIR STU3"
},
"value": "eq081-VQEgP8drUUqCWzHfw3"
},
{
"use": "usual",
"type": {
"text": "INTERNAL"
},
"value": " Z6127"
},
{
"use": "usual",
"type": {
"text": "EPI"
},
"system": "urn:oid:1.2.840.114350.1.13.0.1.7.5.737384.14",
"value": "203711"
},
{
"extension": [
{
"valueString": "xxx-xx-0000",
"url": "http://hl7.org/fhir/StructureDefinition/rendered-value"
}
],
"use": "usual",
"system": "urn:oid:2.16.840.1.113883.4.1"
}
],
"active": true,
"name": [
{
"use": "usual",
"text": "Derrick Lin",
"family": "Lin",
"given": [
"Derrick"
]
}
],
"telecom": [
{
"system": "phone",
"value": "785-555-5555",
"use": "home"
},
{
"system": "phone",
"value": "785-666-6666",
"use": "work"
}
],
"gender": "male",
"birthDate": "1973-06-03",
"deceasedBoolean": false,
"address": [
{
"use": "home",
"line": [
"7324 Roosevelt Ave"
],
"city": "INDIANAPOLIS",
"district": "MARION",
"state": "IN",
"postalCode": "46201",
"country": "US",
"period": {
"start": "2019-05-24"
}
}
],
"maritalStatus": {
"text": "Married"
},
"communication": [
{
"language": {
"coding": [
{
"system": "http://hl7.org/fhir/ValueSet/languages",
"code": "en",
"display": "English"
}
],
"text": "English"
},
"preferred": true
}
],
"managingOrganization": {
"reference": "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/STU3/Organization/enRyWnSP963FYDpoks4NHOA3",
"display": "Epic Hospital System"
}
}
You can now save off Derrick's STU3 FHIR ID taking advantage of Jquery's $.grep() function:
var result = $.grep(data, function(x) { return x.type[n].text == "FHIR STU3"; });
var patientIdSTU3 = result[0].value //We’ll only ever return one FHIR STU3 ID
Now that you have the STU3 ID, you're free to call into STU3 resources. Remember to change your base URL to reference STU3. Here's an example of the same Condition search we did earlier but now using Derrick's STU3 FHIR ID.
var completeSearchString = "https://fhir.epic.com/interconnect-fhir-oauth/api/FHIR/STU3/Condition?patient=" + patientIdSTU3 + "&clinical-status=active"
Of note, one difference you might notice between DSTU2 and STU3 resources is that paging is only supported in STU3 resources. DSTU2 responses come back in one request.
This document describes the FHIR Search result parameters currently available, what they can do, and how to use each of these parameters with Epic FHIR APIs.
Search result parameters modify how results are returned in a Search API’s response. See the table below for the search result parameters that are supported by Epic and the versions in which they are supported.
| Parameter | Supported in DSTU2? | Supported in STU3? | Supported in R4? |
| _id | Yes | Yes | Yes |
| _count | Yes, for the Observation resource only | Yes | Yes |
| _include | No | Yes | Yes |
| _revInclude | No | No | Yes |
The _id parameter is used to indicate a FHIR ID, allowing read-type functionality in a search FHIR API.
So why would you want to use _id in a search API instead of a read API? Well, what if you wanted to perform a read with a FHIR search parameter? The _id parameter allows you to do just that, by using FHIR search parameters while still reading data about a single resource.
GET https://hostname/instance/api/FHIR/STU3/Patient?_id=eYg3-1aJmCMq-umIIq2Njxw3&_include=Patient:generalPractitioner:Practitioner
The _count parameter is used to limit the number of results returned by a search request. Once the number of results specified has been reached, the URL to the next page of results will be generated and included in the response. This URL contains a session ID which returns the next group of _count results. This is useful for resources that could return a large number of results (such as Observation), as using _count can minimize the demand on the server. _count can be set to any number from 1 to 999.
Important note on resources that return many results:
If your search returns more than 1000 results, the search will automatically be broken into pages with 1000 results each, regardless of whether or not you use the _count parameter. This means that your app needs to support this functionality to ensure that you receive all applicable data associated with the API request.
The API response when using the _count parameter behaves differently for STU3 and later requests, versus DSTU2 requests, as described below.
For STU3 and above, look for the link.relation parameter. If link.relation is "next", then use the request in link.url to obtain the next set of resources. Continue until link.relation is "self".
GET https://apporchard.epic.com/interconnect-aocurprd-username/api/FHIR/STU3/Observation?patient=e63wRTbPfr1p8UW81d8Seiw3&category=vital-signs&_count=10
{
"resourceType": "Bundle",
"type": "searchset",
"total": 10,
"link": [
{
"relation": "next",
"url": "https://apporchard.epic.com/interconnect-aocurprd-oauth/api/FHIR/STU3/Observation?patient=e63wRTbPfr1p8UW81d8Seiw3&category=vital-signs&_count=10&sessionID=16-BAF392808B2B11EA92E00050568B7BE6"
}
...{response continues}
The _include parameter is used to return resources related to the initial search result. Any other resource included as a reference can be returned in the response bundle. This reduces the number of requests needed to see information. For example, when searching for a patient's encounters, you can include the encounter providers as well.
In the February 2021 version of Epic and prior versions, included references are returned immediately following the associated search result. Starting in the May 2021 version of Epic for STU3 and R4 FHIR resources, included resource references from all search results are at the end of the response bundle rather than after each individual search result, and each unique referenced resource instance is included only once in the bundle. Consumers of FHIR search results should be able to accept both bundle formats until a future version when we expect all integrations to eventually transition to the latter format.
Epic supports the _include parameter primarily for FHIR search interactions. In addition, it is supported for particular operation types, like Appointment.$find.
For this parameter to work, the Search response must include a reference to another FHIR resource.
General format: _include = [resource you’re searching]:[name of reference element you want included]:[type of resource if element can refer to multiple (optional)]
_include=Immunization:actor:Practitioner_include=Immunization:actor would also work here)_include=Appointment:actor:Patient_include=Appointment:actor:Practitioner_include=Appointment:actor:LocationThe _revInclude parameter (reverse include) is used to return a particular resource, along with other resources that refer to that resource. For this parameter to return results, the FHIR resource specified in the search response must be referenced by the resource specified in the _revInclude parameter.
Parameter format: _revInclude=Provenance:target
The response will have the following format:
| Element | Type | Cardinality | Description |
| target | Reference (resource) | 1..* | The resource this provenance supports |
| recorded | Instant | 1..1 | Timestamp that the activity was recorded/updated |
| agent | Backbone Element | 1..* | Actor involved |
| agent.type | CodeableConcept | 0..1 | How the agent participated |
| agent.who | Reference (Practitioner | Patient | Organization) | 1..1 | Who participated |
| agent.onBehalfOf | Reference (Organization) | 0..1 | Who the agent is representing. |
https://www.example.org/api/FHIR/R4/DocumentReference?_id=eiuHBlNpiGxJwXRUWVqHjN9QaKO0ODrkAJrvUByRLuMc3&_revInclude=Provenance:target
{
"link": [{
"relation": "self",
"url": "https://www.example.org/api/FHIR/R4/Provenance/eC7YEH-XJufbPDHTDFWShEk2b9Ki98xTRyLbhFXwQ6sfcjhyfmeem2nFqdxZYHcS0FhROyzJUToN.o1UE0DQeXQ3"
}],
"fullUrl": "https://www.example.org/api/FHIR/R4/Provenance/eC7YEH-XJufbPDHTDFWShEk2b9Ki98xTRyLbhFXwQ6sfcjhyfmeem2nFqdxZYHcS0FhROyzJUToN.o1UE0DQeXQ3",
"resource": {
"resourceType": "Provenance",
"id": "eC7YEH-XJufbPDHTDFWShEk2b9Ki98xTRyLbhFXwQ6sfcjhyfmeem2nFqdxZYHcS0FhROyzJUToN.o1UE0DQeXQ3",
"target": [{"reference": "DocumentReference/eiuHBlNpiGxJwXRUWVqHjN9QaKO0ODrkAJrvUByRLuMc3"}],
"recorded": "2020-06-23T07:33:12Z",
"agent": [{
"type": {
"coding": [{
"system": "http://terminology.hl7.org/CodeSystem/provenance-participant-type",
"code": "author",
"display": "Author"
}],
"text": "Author"
},
"who": {
"reference": "Practitioner/eIOnxJsdFcfgJ4iy716I3MA3",
"display": "Starter Provider, MD"
},
"onBehalfOf": {"display": "Example Organization"}
},
{
"type": {
"coding": [{
"system": "http://terminology.hl7.org/CodeSystem/provenance-participant-type",
"code": "transmitter",
"display": "Transmitter"
}],
"text": "Transmitter"
},
"who": {
"display": "Example Organization"
}
}]
},
"search": {"mode": "include"}
}
Parameter format: _revInclude=AuditEvent:entity
The response will have the following format:
| Element | Type | Cardinality | Description |
|
type |
Coding |
1..1 |
Type or identifier of the event |
|
recorded |
Instant |
1..1 |
Time when the event was recorded |
|
agent |
BackboneElement |
1..* |
Actors involved in the event |
|
agent.role |
CodeableConcept |
0..* |
Agent role in the event |
|
agent.who |
Reference (PractitionerRole | Practitioner | Organization | Device | Patient | RelatedPerson)
|
0..1 |
Identifier of who participated |
|
agent.requestor |
Boolean |
1..1 |
Whether the user is the initiator |
|
source |
BackboneElement |
1..1 |
The audit event reporter |
|
source.observer |
Reference (PractitionerRole | Practitioner | Organization | Device | Patient | RelatedPerson) |
1..1 |
The identity of the source detecting the event |
|
entity |
BackboneElement |
0..* |
Data or objects used |
|
entity.what |
Reference (Any) |
0..1 |
Specific instance of the resource |
|
entity.detail |
BackboneElement |
0..* |
Additional information about the entity |
|
entity.detail.type |
String |
1..1 |
Name of the property that changed |
|
String |
1..1 |
Property value |
|
|
entity.detail extension (audit-event-detail-state) |
Extension |
0..1 |
Indicates whether the value in entity.detail.valueString is the value before or after the audited event |
https://www.example.org/api/FHIR/R4/MedicationRequest?_id=eiuHBlNpiGxJwXRUWVqHjN9QaKO0ODrkAJrvUByRLuMc3&_revInclude=AuditEvent:entity
{
"link": [{
"relation": "self",
"url": https://www.example.org/api/FHIR/R4/AuditEvent/erLtgh1AreI5Y0dE6YVZxVzXV3FaxnhsMWrsnBmt-JUcxF7D14JKfYlolngfGblRgIoJNa8UzOyGJ38eJBF3aKn94wMPR9m6M.LWkVmDWuRxpwYKzNEloKILbZHuXeidD3
}],
"fullUrl": https://www.example.org/api/FHIR/R4/AuditEvent/erLtgh1AreI5Y0dE6YVZxVzXV3FaxnhsMWrsnBmt-JUcxF7D14JKfYlolngfGblRgIoJNa8UzOyGJ38eJBF3aKn94wMPR9m6M.LWkVmDWuRxpwYKzNEloKILbZHuXeidD3,
"resource": {
"resourceType": "AuditEvent",
"id": "erLtgh1AreI5Y0dE6YVZxVzXV3FaxnhsMWrsnBmt-JUcxF7D14JKfYlolngfGblRgIoJNa8UzOyGJ38eJBF3aKn94wMPR9m6M.LWkVmDWuRxpwYKzNEloKILbZHuXeidD3",
"type": {
"system": "http://open.epic.com/FHIR/StructureDefinition/audit-event-type",
"code": "Modify Order",
"display": "Modify Order"
},
"recorded": "2020-12-09T21:00:03Z",
"agent": [{
"role": [{
"coding": [{
"system": "http://open.epic.com/FHIR/StructureDefinition/audit-event-agent-role",
"code": "Ordering Provider",
"display": "Ordering Provider"
}]
}],
"who": {
"reference": "Practitioner/eEISPNvH1RKgu1t69j6Bx2g3",
"display": "Starter Provider, MD"
},
"requestor": true
}],
"source": {
"observer": {"display": "Example Organization"}
},
"entity": [{
"what": {"reference": "MedicationRequest/eiuHBlNpiGxJwXRUWVqHjN9QaKO0ODrkAJrvUByRLuMc3"},
"detail": [{
"type": "Comment",
"valueString": "Order Modified"
},
{
"type": "Administration instructions",
"valueString": "Administration Instructions edited"
}
}]
}
"search": {"mode": "include"}
}
These test users can be used to authenticate when testing Provider-Facing Standalone OAuth 2.0 workflows with the FHIR sandbox.
Sandbox URI - https://fhir.epic.com/interconnect-fhir-oauth/
FHIR Endpoints - See 'FHIR API Endpoints' on open.epic
|
User |
User Login |
User Password |
|---|---|---|
|
FHIR, USER |
FHIR |
EpicFhir11! |
These are some of the test patients that exist in the Epic on FHIR sandbox.
Sandbox URI - https://fhir.epic.com/interconnect-fhir-oauth/
FHIR Endpoints - See 'FHIR API Endpoints' on open.epic
|
Patient |
FHIR Identifier |
Applicable Resources |
|---|---|---|
|
Camila Lopez |
FHIR: erXuFYUfucBZaryVksYEcMg3 External: Z6129 MRN: 203713 MyChart Login Username: fhircamila MyChart Login Password: epicepic1 |
|
|
Derrick Lin |
FHIR: eq081-VQEgP8drUUqCWzHfw3 External: Z6127 MRN: 203711 MyChart Login Username: fhirderrick MyChart Login Password: epicepic1 |
|
|
Desiree Powell |
FHIR: eAB3mDIBBcyUKviyzrxsnAw3 External: Z6130 MRN: 203714 MyChart Login Username: fhirdesiree MyChart Login Password: epicepic1 |
|
|
Elijah Davis |
FHIR: egqBHVfQlt4Bw3XGXoxVxHg3 External: Z6125 MRN: 203709 |
|
|
Linda Ross |
FHIR: eh2xYHuzl9nkSFVvV3osUHg3 External: Z6128 MRN: 203712 |
|
|
Olivia Roberts |
FHIR: eh2xYHuzl9nkSFVvV3osUHg3 External: Z6131 MRN: 203715 |
|
|
Warren McGinnis |
FHIR: e0w0LEDCYtfckT6N.CkJKCw3 External: Z6126 MRN: 203710 |
|
If you're using the legacy DSTU2 sandbox for testing, here are a few patients you can check out.
Sandbox URI - https://open-ic.epic.com/argonaut/
FHIR Endpoints - See 'FHIR API Endpoints' on open.epic
|
Patient |
Account Details |
Applicable Resources |
|---|---|---|
|
Jessica Argonaut |
FHIR: TUKRxL29bxE9lyAcdTIyrWC6Ln5gZ-z7CLr2r-2SY964B MyChart Login Username: fhirjessica MyChart Login Password: n/a Note: This account is only enabled as a proxy account |
|
|
Jason Argonaut |
FHIR: Tbt3KuCY0B5PSrJvCu2j-PlK.aiHsu2xUjUM8bWpetXoB MyChart Login Username: fhirjason MyChart Login Password: epicepic1 Note: This account has proxy access to fhirjessica |
|
|
Daisy Tinsley |
FHIR: TbsWqA46u3BtlZT2KSkx5cZOT1o0mGbI3VPAGXv6XcdEB MyChart Login Username: fhirdaisy MyChart Login Password: epicepic1 |
|
Some FHIR APIs may return different data when the application is used in a patient-facing context. This typically occurs because data that should not be visible to a patient is filtered out of FHIR API responses in patient-facing applications. Below are some examples of possible differences in the results returned by a FHIR API:
pseudoephedrine instead of PSEUDOPHEDRINE HCL 30 MG PO TABS.Community members may choose to disable this filtering functionality for their Epic instance, resulting in near identical behavior between patient-facing FHIR API responses and the response of apps with other audiences.
Epic recommends that you thoroughly test each API at each Community Member’s site prior to a go-live in production to ensure that you understand the behavior of each API for that community member’s Epic deployment.
Client IDs for USCDI apps will automatically download to a community member’s Epic instances when all of the following conditions are met:
Client IDs for CCDS apps will automatically download to a community member’s Epic instances when all of the following conditions are met:
Any applications that do not meet all of the above criteria will need to be manually downloaded to the community member's Epic instances. Steps to do so can be found in the App Creation and Request Process guide.
† Only the following DSTU2 FHIR APIs qualify for MU3 auto-download.
Epic's support for vaccine credentials using the SMART Health Cards specification is evolving. The content on this page might change without notice.
A vaccine credential binds an individual’s demographic information with information about their lab tests or vaccine history into a package that is machine-readable and digitally signed by the issuer. Unlike a paper vaccine card, a vaccine credential is verifiable and therefore much more difficult to tamper with or counterfeit.
A CDC vaccine card, widely issued in the United States to patients when they receive a COVID-19 vaccination.
This document was designed to support health wallets, pass apps, and verifiers, in designing apps and technologies that can consume a patient-provided SMART Health Card. We note particularly that any developer creating a pass app should also consider how verifiers using that pass app will interact with patients who do not have access to technology and present only with their ID and a printed SMART Health Card. Any verifier that requires patients to download a specific type of pass app (and thus, cannot read and interact with printed SMART Health Cards) is disadvantaging individuals without technology. SMART Health Cards were specifically designed to provide patient access regardless of technological ability or sophistication.
In other words, if you require an individual to download and present a certain type of app to enter your venue, you have not implemented the specification correctly.
A SMART Health Card is a standard for representing a vaccine credential. The SMART Health Cards standard is open, interoperable, and built on top of HL7 FHIR and compatible with W3C's Verifiable Credentials. It's designed to be:
A SMART Health Card contains very limited patient demographics, and either information about the patient's COVID-19 immunization or COVID-19 lab result.
Technically, a SMART Health Card is a JSON object containing a JWS of compressed JSON, consisting of a FHIR Patient and either one or two FHIR Immunizations; or a FHIR Observation resource. The card can be represented as a file ending in the .smart-health-card extension, or as a QR code printed on paper or displayed digitally.
You can learn more about SMART Health Cards by visiting the following websites:
Epic generates SMART Health Cards in two different ways and via a few different workflows:
Patients can share QR codes either directly from a mobile device or from a piece of paper. You should test and validate that your app can consume the QR code from both a mobile device and from a piece of paper.
A patient can download their SMART Health Card from MyChart onto their device. If you're developing an app that can run on a patient's device, alongside MyChart, you should associate your app with the .smart-health-card filename extension.
Every SMART Health Card can be represented as a QR code. Typical QR scanner apps expect the QR code to contain a URL that can be navigated to in a browser, but a SMART Health Card's QR code does not contain an http:// URL. Rather, the content begins with an shc:/ prefix, followed by a series of numbers and optionally forward slashes (/).
For example, a SMART Health Card QR code could contain this example content after it is scanned:
shc:/567629595326546034602925407728043360287028647167452228092864456652064567322455425662713655612967382737094440447142272560543945364126252454415527384355065405373633654575390303603122290952432060346029243740446057360106413733531270742335036958065345203372766522453157257438663242742309774531624034227003622673375938313137693259503100426236772203355605036403580035610300766508583058374270060532535258081003347207250832110567524430725820265707614406667441643124353569754355376170447732541065607642436956282976307276247374426657326827736143256004577460541121230968766729300406344232537345706367327527360526620626030777047434662721590753712525295755717157712404305365553050007570070626252762326973342068033331323970433259453532396071684011083877646011585542067525276750403569746574042500432127583065602700296834605068374126617637383032031153273532295552400564655669374044767208283743690777676126004361576025612868262976107611767042442744504570773124097729726134647000600635240740664475562634400569324229237641072230287177047474320721676355073560542058377743647371335212506320077300352940590840740926502974284434626571632106437507760408126227344173035234272224650859284424550330072738216709675476296859290842564163266200100030407726503740243343666063287100680677296841286766396657316871405227413263621127776161647443056825046903656367560042552754107309332612290435433150635250555600416734505731035241562857000866406707250066585029295368623020723771290300716970507307715829230409632369722208220022421235364507226273407623637673266125102552327255034322275824010800676966507066627420335210701037520576422230612371756123652765287762007444002131666470397727224500564164325437330542095250237703346428534576030771757133406430361224385420
The numbers following the shc:/ prefix are the content of the SMART Health Card and must be numerically decoded.
SMART Health Cards' QR codes represent characters as their ASCII code. The SMART Health Cards specification defines a simple algorithm to represent each character from the JWS as a two-digit number. Following the prefix, each pair of digits is converted into a single character by adding 45 to determine the encoded letter that the integer represents.
For example, the first pair of digits in the numerically encoded SMART Health Card example above is 56. By adding our offset constant 45 to 56, the value translates to ASCII's lower-case e (Chr(101) = "e"). The constant 45 was chosen because 45 is the ASCII value for "-", which is the lowest character that can exist in our Base64-URL encoded content.
Decoding the string proceeds as follows:
56 + 45 = e
76 + 45 = y
29 + 45 = J
Etc.
When parsing is complete, the above shc:/ string resolves to the following JWS:
eyJhbGciOiJFUzI1NiIsImtpZCI6ImZoa3ZpMEdWektQdjJpSHR6YUYtWHFicTZQVGFEcVdHSXd3c2RQNnZxT00iLCJ6aXAiOiJERUYifQ.3VRNb9swDP0rg3bZANuynCZLfFwSoMWwD6zZLkUOCs0kGvRhSLLRrMh_L-WkQzC0Pe20m0g-Pj0-yn5gKgRWs32Mbag570Ou4F5M82paYKugAGf4jY3owVmLEPPrxXdRjsYzMc7niyWXreIJyKuyEvwWofMqHvjXFi1fwic8BD6qypJK13OWMbvZslpMxHQ2Gk3G04z1wOoHBh4btFFJfdttftE1KbndK_-xs43GFHkMrvOAq0NLMTsXMhZPMTitqU85Szmi8gdW3xFHp_UPrwnw1F-XBHgKniH-JqOi_qRVGjyRSKM08bHPMJdaU2mnerRUYyu5IRXr4zpjG-XjfiFjIqGJy7y8ysWYHY_ZszLE6zJujOms-i3PE4UoYxeGOU2rMWJDyV4CKItz1wwM4Bpld4PicAgRzXmvtNa9_lA4v-PJUh5Uw6G_JwIYOkntlB3Xx4y159kHOVv0aOHCEn5hIYEd0K4HSBp6pcyJqhJ5WeVlGk-7-KUzG_RUENXoilIt-q3zJqVIpoTofLqtUaHVMlk8HzjjmwX2qF1r0nlpe-WdHc7v6NG9J1PXL_la_de-VpO_fL0aVeIf-5oUp4F-og_JJbqkKAuRtJ0-trs_v4tgJD16lDruC5C-CW9PQZ4CkvUyDlyvGjF7FaMud0XCHgE.5-pro_sokwANa7s7Ra2yWCKjDtxjDnHnIzk-wY-BLomsTzHCZ-eVmMcRN2W6a_Dz0OmIbZy04txtNUmKQ9EScA
See the SMART Health Cards specification for an alternate explanation of numerical encoding.
In some cases, the underlying demographic and clinical data stored in a SMART Health Card QR code might simply be too large for a single QR code. If so, the SMART Health Card is "chunked" -- split across multiple QR codes that must be scanned and reassembled before any data can be accessed. In this case, the shc:/ prefix is appended with two additional values, delimited by forward slashes ("/"). The first value defines the order of the current QR code for reassembly and the second is the total number of QR codes required to reassemble the data.
For example, a SMART Health Card of 3500 characters is split across three distinct QR codes. The prefix of the first QR code will be: shc:/1/3/, the second: shc:/2/3/ and the third: shc:/3/3/. The contents of all three QR codes (following the final forward slash) must be concatenated in order before inflation.
Requiring multiple QR codes to receive a single SMART Health Card is undesirable and likely confusing to consumers. Epic will rarely place so much information in a single SMART Health Card such that chunking the data across multiple QR codes is necessary. However, apps consuming these QR codes must be prepared to scan and assemble multiple QR codes.
In addition to presenting a QR code to a scanner, a consumer can also download a file to share a SMART Health Card. In this case, there's no QR code, no numeric encoding, and no chunking. The SMART Health Card is represented as a JWS wrapped in a simple JSON array. The filename extension of this file will always be ".smart-health-card".
Here's an example of a .smart-health-card file containing a single SMART Health Card:
{
"verifiableCredential": [
"eyJhbGciOiJFUzI1NiIsImtpZCI6ImZoa3ZpMEdWektQdjJpSHR6YUYtWHFicTZQVGFEcVdHSXd3c2RQNnZxT00iLCJ6aXAiOiJERUYifQ.3VRNb9swDP0rg3bZANuynCZLfFwSoMWwD6zZLkUOCs0kGvRhSLLRrMh_L-WkQzC0Pe20m0g-Pj0-yn5gKgRWs32Mbag570Ou4F5M82paYKugAGf4jY3owVmLEPPrxXdRjsYzMc7niyWXreIJyKuyEvwWofMqHvjXFi1fwic8BD6qypJK13OWMbvZslpMxHQ2Gk3G04z1wOoHBh4btFFJfdttftE1KbndK_-xs43GFHkMrvOAq0NLMTsXMhZPMTitqU85Szmi8gdW3xFHp_UPrwnw1F-XBHgKniH-JqOi_qRVGjyRSKM08bHPMJdaU2mnerRUYyu5IRXr4zpjG-XjfiFjIqGJy7y8ysWYHY_ZszLE6zJujOms-i3PE4UoYxeGOU2rMWJDyV4CKItz1wwM4Bpld4PicAgRzXmvtNa9_lA4v-PJUh5Uw6G_JwIYOkntlB3Xx4y159kHOVv0aOHCEn5hIYEd0K4HSBp6pcyJqhJ5WeVlGk-7-KUzG_RUENXoilIt-q3zJqVIpoTofLqtUaHVMlk8HzjjmwX2qF1r0nlpe-WdHc7v6NG9J1PXL_la_de-VpO_fL0aVeIf-5oUp4F-og_JJbqkKAuRtJ0-trs_v4tgJD16lDruC5C-CW9PQZ4CkvUyDlyvGjF7FaMud0XCHgE.5-pro_sokwANa7s7Ra2yWCKjDtxjDnHnIzk-wY-BLomsTzHCZ-eVmMcRN2W6a_Dz0OmIbZy04txtNUmKQ9EScA"
]
}
The .smart-health-card files downloaded from MyChart web or mobile will contain one or two entries in the verifiableCredential JSON array. Each array entry is a self-contained SMART Health Card.
Regardless of how a SMART Health Card is received -- a QR code scan or a file download, the same steps are used to verify and access the information contained within it.
A JWS, including our SMART Health Card JWS, is made up of three, Base64-encoded parts: JOSE header, a payload, and a signature. Per RFC 7515, these three parts are concatenated together with periods.
The JOSE (Javascript Object Signing and Encryption) Header identifies the algorithms used to sign and compress the payload and a unique identifier of the public key to be used to verify the signature.
For example, the JOSE header from the above JWS is:
eyJhbGciOiJFUzI1NiIsImtpZCI6ImZoa3ZpMEdWektQdjJpSHR6YUYtWHFicTZQVGFEcVdHSXd3c2RQNnZxT00iLCJ6aXAiOiJERUYifQ
Upon Base64-decoding it (and formatting for readability):
{
"alg": "ES256",
"kid": "fhkvi0GVzKPv2iHtzaF-Xqbq6PTaDqWGIwwsdP6vqOM",
"zip": "DEF"
}
alg – the algorithm used to sign the JWS.kid – a "key identifier" which is used to find the public key for validating the signature.zip – the compression algorithm used to deflate the payload. Note that the JWS standard does not define the zip header; the SMART Health Card uses borrows it from the closely related JWT standard.In the SMART Health Card standard, the alg header will always be "ES256" and the zip header will always be "DEF". In Epic's implementation of the standard, only the kid header will change, as it uniquely identifies the public key used by the healthcare delivery organization that issued the SMART Health Card. The public key may be rotated periodically.
The payload of a SMART Health Card JWS (that is, the second of the three period-delimited pieces in the JWS) is base64-encoded, compressed JSON. The JSON is compressed with the DEFLATE algorithm.
The DEFLATE algorithm is open source and has significant library support. DEFLATE is the same compression algorithm used by gzip but doesn't make use of the gzip header and footer. See RFC 1951 for more information about this compression algorithm.
As an example, starting with this JWS payload from our example above,
3VRNb9swDP0rg3bZANuynCZLfFwSoMWwD6zZLkUOCs0kGvRhSLLRrMh_L-WkQzC0Pe20m0g-Pj0-yn5gKgRWs32Mbag570Ou4F5M82paYKugAGf4jY3owVmLEPPrxXdRjsYzMc7niyWXreIJyKuyEvwWofMqHvjXFi1fwic8BD6qypJK13OWMbvZslpMxHQ2Gk3G04z1wOoHBh4btFFJfdttftE1KbndK_-xs43GFHkMrvOAq0NLMTsXMhZPMTitqU85Szmi8gdW3xFHp_UPrwnw1F-XBHgKniH-JqOi_qRVGjyRSKM08bHPMJdaU2mnerRUYyu5IRXr4zpjG-XjfiFjIqGJy7y8ysWYHY_ZszLE6zJujOms-i3PE4UoYxeGOU2rMWJDyV4CKItz1wwM4Bpld4PicAgRzXmvtNa9_lA4v-PJUh5Uw6G_JwIYOkntlB3Xx4y159kHOVv0aOHCEn5hIYEd0K4HSBp6pcyJqhJ5WeVlGk-7-KUzG_RUENXoilIt-q3zJqVIpoTofLqtUaHVMlk8HzjjmwX2qF1r0nlpe-WdHc7v6NG9J1PXL_la_de-VpO_fL0aVeIf-5oUp4F-og_JJbqkKAuRtJ0-trs_v4tgJD16lDruC5C-CW9PQZ4CkvUyDlyvGjF7FaMud0XCHgE
we Base64 URL-decode and inflate to arrive at the actual JSON content. The JSON of a SMART Health Card is made up of a header and a few FHIR resources.
A SMART Health Card's header elements identify if the card contains immunization or lab result information, a unique url for the organization that issued the card and the time at which the card was issued.
iss – Append /.well-known/jwks.json to this url to access the JSON Wek Key Set containing a public key for verification of the JWS signature. See SMART Health Cards & Trust for additional information.nbf – The time at which the SMART Health Card was issued (per RFC 7519). Epic generates SMART Health Cards on-demand, so this timestamp will correspond to the time at which the card was accessed by the patient.type – Identifies the SMART Health Card as containing either COVID-19 vaccination or lab result. Epic-generated SMART Health Cards will always be one of the following:
credentialSubject – Contains a FHIR Bundle of a Patient resource, either one or two FHIR Immunization resources, or an Observation resource representing a lab result.This is an example of the SMART Health Card header describing an immunization card, issued on April 20, 2021.
{
"iss": "https://vs-icx18-28.epic.com/Interconnect-HDR1035915-CDE/api/epic/2021/Security/Open/EcKeys/32001/SHC",
"nbf": 1618933658,
"type": ["https://smarthealth.cards#health-card", "https://smarthealth.cards#covid19", "https://smarthealth.cards#immunization"],
"vc": {
"credentialSubject": {
//payload removed for readability
}
}
}
The credentialSubject element from the SMART Health Card header defines the version of FHIR and contains a Bundle of FHIR resources.
fhirVersion – Version of FHIR resources contained in this SMART Health Card. Epic generated SMART Cards will always use FHIR R4 resources, represented in this field as “4.0.1”.fhirBundle – A Bundle of type collection containing two to three FHIR resources. Each entry in the Bundle is a distinct FHIR resource.Here's an example of a credentialSubject containing a fhirBundle:
{
"credentialSubject": {
"fhirVersion": "4.0.1",
"fhirBundle": {
"resourceType": "Bundle",
"type": "collection",
"entry": [
{ //FHIR resource },
{ //FHIR resource #2 },
{ //another FHIR resource! },
}
}
}
SMART Health Cards always contain a FHIR Patient resource. Unlike a typical Patient resource, the only information in the resource is the patient's given and family name, and date of birth.
When consuming a SMART Health Card, the demographics in this Patient resource are verified against the user's identity.
{
"resource": {
"resourceType": "Patient",
"name": [{
"family": "McCall",
"given": ["Table"]
}],
"birthDate": "2000-04-15"
}
}
Importantly, possession of a SMART Health Card does not prove a patient's identity. In fact, patient caregivers, for example: parents, may access and download the SMART Health Cards of their wards. Pass apps and verifiers must verify identity.
When a patient shares a SMART Health Card with a verifier, the verifier is expected to validate the patient's identity independently. For example, if a patient presents their driver's license along with their SMART Health Card, the verifier should confirm that the demographics within the SMART Health Card (specifically, the name and date of birth), match those on the driver's license.
A SMART Health Card documenting a vaccination contains one or two FHIR Immunization resources. The below example describes a Pfizer immunizations completed on February 1.
status – contains the value “completed”vaccineCode – contains a CVX code identifying the given vaccine.occurrenceDateTime – the date on which the vaccine was administeredlotNumber – the product lot number, further identifying the vaccineactor – contains the name of the organization at which the vaccine was administered. Will not be present if administering organization is unknown.
{
"resource": {
"resourceType": "Immunization",
"status": "completed",
"vaccineCode": {
"coding": [{
"system": "http://hl7.org/fhir/sid/cvx",
"code": "208"
}]
},
"patient": {
"reference": "Patient/resource:0"
},
"occurrenceDateTime": "2021-02-01",
"lotNumber": "1234",
"performer": [{
"actor": {
"display": "Current Development Environment (CDE)"
}
}]
}
}
A SMART Health Card documenting a lab result contains one FHIR Observation resource. The below example describes a negative lab test resulted on November 23, 202.
status – contains the value "final"code – contains a LOINC code identifying the lab test, if knowneffectiveDateTime – the time at which the lab test was resultedperformer – contains the name of the organization at which the test was performed.value – the result of a COVID-19 lab test may be represented as a SNOMED code, a quantity, or a string.
{
"resource": {
"resourceType": "Observation",
"status": "final",
"code": {
"coding": [{
"system": "http://loinc.org",
"code": "882-1"
}]
},
"subject": {
"reference": "Patient/resource:0"
},
"effectiveDateTime": "2020-11-23T06:00:00Z",
"performer": [{
"display": "Health system"
}],
"valueString": "Negative"
}
}
A SMART Health Card is verifiable because its signed payload can be verified against a trusted public key. Each issuer publishes a JSON Web Key Set (JWKS) containing at least one public key. Typically, each healthcare organization that uses Epic acts as a distinct issuer.
A verifier must determine which issuers to trust. Issuers participating in the Vaccine Credential Initiative have shared their publicly accessible JSON Web Key Set URLs in this directory:
Verifiers should consider trusting and caching all of the public keys provided in the key sets from this directory.
An issuer's key set is discoverable during verification by appending "/.well-known/jwks.json" to a SMART Health Card's iss value. For example, iss value in the above SMART Health Cards is an inaccessiable, url internal to Epic: https://vs-icx18-28.epic.com/Interconnect-HDR1035915-CDE/api/epic/2021/Security/Open/EcKeys/32001/SHC
HTTP Get https://vs-icx18-28.epic.com/Interconnect-HDR1035915-CDE/api/epic/2021/Security/Open/EcKeys/32001/SHC/.well-known/jwks.json
{
"keys": [{
"x": "gfoeoAb2l-hqEHXyZIBqa1OObZ7Tunx5hlYRXtnPJwg",
"y": "HcBgiLJ53BFqOp5lxiMUz5Jsik9DtM286pyWv2hVKNA",
"kid": "fhkvi0GVzKPv2iHtzaF-Xqbq6PTaDqWGIwwsdP6vqOM",
"use": "sig",
"kty": "EC",
"alg": "ES256",
"crv": "P-256"
}]
}
The key identifier from the JWKS's kid element corresponds to kid element in the header of the SMART Health Card's JWS. Epic issued SMART Health Cards are signed using ECDSA P-256 SHA-256.
Verifiers should use standard security libraries to verify SMART Health Card signatures. Refer to Appendix A.3 of RFC 7515 to understand how Epic’s signature is calculated and formatted.
While it is not an exhaustive list, nor maintained or affiliated with Epic, the following resources might be helpful:
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