diff --git a/controller/editorapicontroller.php b/controller/editorapicontroller.php
index 3f91a0d3..cb0cb5c6 100644
--- a/controller/editorapicontroller.php
+++ b/controller/editorapicontroller.php
@@ -303,7 +303,7 @@ public function config($fileId, $filePath = null, $shareToken = null, $version =
 				"title" => $fileName,
 				"url" => $fileUrl,
 				"referenceData" => [
-					"fileKey" => $file->getId(),
+					"fileKey" => (string)$file->getId(),
 					"instanceId" => $this->config->getSystemValue("instanceid", true),
 				],
 			],
diff --git a/controller/editorcontroller.php b/controller/editorcontroller.php
index 517b73a0..d59a8a9d 100644
--- a/controller/editorcontroller.php
+++ b/controller/editorcontroller.php
@@ -648,7 +648,7 @@ public function reference($referenceData, $path = null) {
 			"path" => $userFolder->getRelativePath($file->getPath()),
 			"key" => $key,
 			"referenceData" => [
-				"fileKey" => $file->getId(),
+				"fileKey" => (string)$file->getId(),
 				"instanceId" => $this->config->getSystemValue("instanceid", true),
 			],
 			"url" => $this->getUrl($file, $user),