diff --git a/languages/golang/templates/client.mustache b/languages/golang/templates/client.mustache
index e9f0ecf..d420b1f 100644
--- a/languages/golang/templates/client.mustache
+++ b/languages/golang/templates/client.mustache
@@ -345,7 +345,7 @@ func (c *APIClient) prepareRequest(
 	var body *bytes.Buffer
 
 	// Detect postBody type and post.
-	if postBody != nil {
+	if !IsNil(postBody) {
 		contentType := headerParams["Content-Type"]
 		if contentType == "" {
 			contentType = detectContentType(postBody)