diff --git a/modules/erp/import-integration/shopify-api.php b/modules/erp/import-integration/shopify-api.php
index 1b0abaf..7b5394c 100644
--- a/modules/erp/import-integration/shopify-api.php
+++ b/modules/erp/import-integration/shopify-api.php
@@ -107,7 +107,11 @@ function shopify_graphql_query(array $env, string $query, array $variables = [])
 
     $credentials = shopify_api_credentials($env);
     $token = shopify_api_access_token($env);
-    $body = json_encode(['query' => $query, 'variables' => $variables], JSON_THROW_ON_ERROR | JSON_UNESCAPED_SLASHES);
+    $request = ['query' => $query];
+    if ($variables !== []) {
+        $request['variables'] = $variables;
+    }
+    $body = json_encode($request, JSON_THROW_ON_ERROR | JSON_UNESCAPED_SLASHES);
     $response = shopify_api_request_json(
         'https://' . $credentials['shop'] . '/admin/api/' . $credentials['api_version'] . '/graphql.json',
         'POST',