diff --git a/types.go b/types.go
index 8f9f31a..cbfc229 100644
--- a/types.go
+++ b/types.go
@@ -801,8 +801,8 @@ type (
 
 	// PaymentSource structure
 	PaymentSource struct {
-		Card  *PaymentSourceCard  `json:"card"`
-		Token *PaymentSourceToken `json:"token"`
+		Card  *PaymentSourceCard  `json:"card,omitempty"`
+		Token *PaymentSourceToken `json:"token,omitempty"`
 	}
 
 	// PaymentSourceCard structure