A real SMART on FHIR standalone launch against the free Anpheros sandbox: OAuth 2.0 authorization code with PKCE, then FHIR R4 reads and writes. Every request and response is shown below.
Sandbox only. You sign in and create a test record; do not enter real health information. The app writes two synthetic observations to that record to show a write.
Standalone launch · public client · PKCE (S256)
Want it on your own key? Get a free sandbox · Read SMART App Launch, explained · Code: smart-app-launch starter