diff --git a/docker/config.json.template b/docker/config.json.template
index 0711374..d41afce 100644
--- a/docker/config.json.template
+++ b/docker/config.json.template
@@ -1,3 +1,3 @@
 {
-  "wsUrl": "ws://${WEBSOCKET_HOST}:${WEBSOCKET_PORT}/websocket"
+  "wsUrl": "${WEBSOCKET_SCHEME}${WEBSOCKET_HOSTNAME}:${WEBSOCKET_PORT}/websocket"
 }
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index e36867a..cabb30e 100755
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -1,3 +1,5 @@
 #!/bin/sh
 
-envsubst < /config.json.template > "/usr/share/nginx/html/config.json"
+WEBSOCKET_SCHEME="${WEBSOCKET_SCHEME:-ws://}" \
+  WEBSOCKET_HOSTNAME="${WEBSOCKET_HOSTNAME:-${WEBSOCKET_HOST}}" \
+  envsubst < /config.json.template > "/usr/share/nginx/html/config.json"