diff --git a/src/model/sns.rs b/src/model/sns.rs
index 552fe9b..688cd25 100644
--- a/src/model/sns.rs
+++ b/src/model/sns.rs
@@ -6,6 +6,19 @@
 //! [0]: https://docs.aws.amazon.com/sns/latest/dg/sns-message-and-json-formats.html
 use serde::Deserialize;
 
+/// Union for all known SNS message types
+///
+/// This type can be used to deserialize an arbitrary SNS message into the
+/// appropriate type, based on the value of the `Type` field in the JSON
+/// document.
+#[derive(Deserialize)]
+#[serde(tag = "Type")]
+pub enum Message {
+    SubscriptionConfirmation(SubscriptionConfirmationMessage),
+    UnsubscribeConfirmation(UnsubscribeConfirmationMessage),
+    Notification(NotificationMessage),
+}
+
 /// SNS Subscription confirmation message
 ///
 /// See also: [HTTP/HTTPS subscription confirmation JSON format][0]
@@ -14,8 +27,6 @@ use serde::Deserialize;
 #[derive(Deserialize)]
 #[serde(rename_all = "PascalCase")]
 pub struct SubscriptionConfirmationMessage {
-    #[serde(rename = "Type")]
-    pub message_type: String,
     #[serde(rename = "MessageId")]
     pub message_id: String,
     pub token: String,
@@ -38,8 +49,6 @@ pub struct SubscriptionConfirmationMessage {
 #[derive(Deserialize)]
 #[serde(rename_all = "PascalCase")]
 pub struct NotificationMessage {
-    #[serde(rename = "Type")]
-    pub message_type: String,
     #[serde(rename = "MessageId")]
     pub message_id: String,
     pub topic_arn: String,
@@ -61,8 +70,6 @@ pub struct NotificationMessage {
 #[derive(Deserialize)]
 #[serde(rename_all = "PascalCase")]
 pub struct UnsubscribeConfirmationMessage {
-    #[serde(rename = "Type")]
-    pub message_type: String,
     #[serde(rename = "MessageId")]
     pub message_id: String,
     pub token: String,
diff --git a/src/sns/sig.rs b/src/sns/sig.rs
index 0624cb4..382e5b7 100644
--- a/src/sns/sig.rs
+++ b/src/sns/sig.rs
@@ -171,7 +171,7 @@ impl SignatureVerifier for SubscriptionConfirmationMessage {
         s.push_str(&self.topic_arn);
         s.push('\n');
         s.push_str("Type\n");
-        s.push_str(&self.message_type);
+        s.push_str("SubscriptionConfirmation");
         s.push('\n');
         s
     }
@@ -206,7 +206,7 @@ impl SignatureVerifier for NotificationMessage {
         s.push_str(&self.topic_arn);
         s.push('\n');
         s.push_str("Type\n");
-        s.push_str(&self.message_type);
+        s.push_str("Notification");
         s.push('\n');
         s
     }
@@ -242,7 +242,7 @@ impl SignatureVerifier for UnsubscribeConfirmationMessage {
         s.push_str(&self.topic_arn);
         s.push('\n');
         s.push_str("Type\n");
-        s.push_str(&self.message_type);
+        s.push_str("UnsubscribeConfirmation");
         s.push('\n');
         s
     }