diff --git a/src/Internal/GenericExporter.php b/src/Internal/GenericExporter.php
index 4c9ec3d..ba2e7dd 100644
--- a/src/Internal/GenericExporter.php
+++ b/src/Internal/GenericExporter.php
@@ -113,7 +113,7 @@ public function exportArray(array $array, array $path = []) : array
             $isLast = (++$current === $count);
 
             $newPath = $path;
-            $newPath[] = $key;
+            $newPath[] = (string) $key;
 
             $exported = $this->export($value, $newPath);