diff --git a/docker-compose.yml b/docker-compose.yml
index 82a1206..a6237fa 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -69,6 +69,7 @@ services:
     # set custom token
     command: start-notebook.py --NotebookApp.token='${JUPYTER_TOKEN}'
     environment:
+      FHIR_VALIDATION_VALIDATOR_API_URL: ${FHIR_VALIDATION_VALIDATOR_API_URL}
       # set credentials in .env so this docker-compose.yml can be fully versioned in git!
       FHIR_VALIDATION_DATASOURCE_BASEURL: ${FHIR_VALIDATION_DATASOURCE_BASEURL}
       FHIR_VALIDATION_DATASOURCE_AUTH_NAME: ${FHIR_VALIDATION_DATASOURCE_AUTH_NAME}