diff --git a/docs/data-source-firebase.md b/docs/data-source-firebase.md
index 47f1d633..f6e823ae 100644
--- a/docs/data-source-firebase.md
+++ b/docs/data-source-firebase.md
@@ -29,7 +29,7 @@ exports.dataSources = {
   firebase: args => new FirebaseDataSource({
     config: {
       credential: admin.credential.cert(cert),
-      databaseURL,
+      databaseUrl,
     },
     path: args.key,
   }),
@@ -81,4 +81,4 @@ export default (
     </array>
   </root>
 )
-``` -->
\ No newline at end of file
+``` -->