diff --git a/dropzone/dropzone-tests.ts b/dropzone/dropzone-tests.ts
index e15d6e038..3893f7c1a 100644
--- a/dropzone/dropzone-tests.ts
+++ b/dropzone/dropzone-tests.ts
@@ -131,6 +131,13 @@ dropzoneWithOptionsVariations = new Dropzone(".test", {
 	clickable: ["test", document.getElementById("test")]
 });
 
+dropzoneWithOptionsVariations = new Dropzone(".test", {
+    success: (file:DropzoneFile, response:Object) => console.log(file, response)
+});
+dropzoneWithOptionsVariations = new Dropzone(".test", {
+    success: (file:DropzoneFile, response:string) => console.log(file, response)
+});
+
 const dropzone = new Dropzone(".test");
 
 dropzone.enable();
diff --git a/dropzone/dropzone.d.ts b/dropzone/dropzone.d.ts
index 93f9ca25b..5588ac48d 100644
--- a/dropzone/dropzone.d.ts
+++ b/dropzone/dropzone.d.ts
@@ -96,7 +96,7 @@ interface DropzoneOptions {
 	sending?(file:DropzoneFile, xhr:XMLHttpRequest, formData:{}):void;
 	sendingmultiple?(files:DropzoneFile[], xhr:XMLHttpRequest, formData:{}):void;
 
-	success?(file:DropzoneFile, responseText:string):void;
+	success?(file: DropzoneFile, response: Object|string): void;
 	successmultiple?(files:DropzoneFile[], responseText:string):void;
 
 	canceled?(file:DropzoneFile):void;