diff --git a/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache b/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
index 056e0dbb2677..4f30b1f679b7 100644
--- a/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
@@ -238,7 +238,12 @@ export class {{classname}} extends runtime.BaseAPI {
         {{/isListContainer}}
         {{^isListContainer}}
         if (requestParameters.{{paramName}} !== undefined) {
+            {{#isPrimitiveType}}
             formParams.append('{{baseName}}', requestParameters.{{paramName}} as any);
+            {{/isPrimitiveType}}
+            {{^isPrimitiveType}}
+            formParams.append('{{baseName}}', new Blob([JSON.stringify({{{dataType}}}ToJSON(requestParameters.{{paramName}}))], { type: "application/json", }));
+            {{/isPrimitiveType}}
         }
 
         {{/isListContainer}}