SMART App Launch
2.2.0 - STU 2.2 International flag

SMART App Launch, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 2.2.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of and changes regularly. See the Directory of published versions

Client Authentication: Symmetric (shared secret)

Profile Audience and Scope

This profile describes SMART’s client-confidential-symmetric authentication mechanism. It is intended for SMART App Launch clients that can maintain a secret but cannot manage asymmetric keypairs. For clients that can manage asymmetric keypairs, Asymmetric Authentication is preferred. This profile is not intended for SMART Backend Services clients.

Authentication using a client_secret

If a client has registered for Client Password authentication (i.e., it possesses a client_secret that is also known to the EHR), the client authenticates by supplying an Authorization header with HTTP Basic authentication, where the username is the app’s client_id and the password is the app’s client_secret.


If the client_id is “my-app” and the client_secret is “my-app-secret-123”, then the header uses the value B64Encode(“my-app:my-app-secret-123”), which converts to bXktYXBwOm15LWFwcC1zZWNyZXQtMTIz. This gives the app the Authorization token for “Basic Auth”.

GET header:

Authorization: Basic bXktYXBwOm15LWFwcC1zZWNyZXQtMTIz