diff --git a/src/core/Rt.js b/src/core/Rt.js
index ccc4479..ed6dccd 100644
--- a/src/core/Rt.js
+++ b/src/core/Rt.js
@@ -171,7 +171,13 @@ export class Rt {
 				if (reqOpts.vars instanceof FormData) {
 
 					for (const [key, value] of reqOpts.vars.entries()) {
-						fdata.set(key, value);
+						
+						if (key.endsWith('[]')) {
+							fdata.append(key, value);
+						}
+						else {
+							fdata.set(key, value);
+						}		
 					}
 				}
 				else {