diff --git a/protocol/json/client.go b/protocol/json/client.go
index 0707904..33f9f30 100644
--- a/protocol/json/client.go
+++ b/protocol/json/client.go
@@ -33,8 +33,8 @@ type clientRequest struct {
 // clientResponse represents a JSON-RPC response returned to a client.
 type clientResponse struct {
 	Version string      `json:"jsonrpc"`
-	Result  interface{} `json:"result"`
-	Error   error       `json:"error"`
+	Result  interface{} `json:"result,omitempty"`
+	Error   error       `json:"error,omitempty"`
 	ID      interface{} `json:"id"`
 }