diff --git a/src/message/event/mod.rs b/src/message/event/mod.rs
index 0952663..15f2f95 100644
--- a/src/message/event/mod.rs
+++ b/src/message/event/mod.rs
@@ -1,5 +1,8 @@
 use serde::{Deserialize, Serialize};
 
+pub const MESSAGE_EVENT_RESPONSE_STATUS_INSTANT: &str = "INSTANT";
+pub const MESSAGE_EVENT_RESPONSE_STATUS_SCHEDULED: &str = "SCHEDULED";
+
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
 pub struct MessageEventResponse {
     pub id: uuid::Uuid,