diff --git a/relay-server/src/utils/tus.rs b/relay-server/src/utils/tus.rs
index 9969ab6efb5..1fc89bd83b6 100644
--- a/relay-server/src/utils/tus.rs
+++ b/relay-server/src/utils/tus.rs
@@ -92,6 +92,7 @@ pub struct Metadata {
     /// The [`AttachmentType`] of the upload.
     ///
     /// Used for preliminary rate-limiting checks.
+    #[serde(default)]
     pub attachment_type: AttachmentType,
 }
 
@@ -384,11 +385,21 @@ mod tests {
     #[test]
     fn test_parse_sentry_metadata_invalid_json() {
         assert!(matches!(
-            parse_sentry_metadata("e30="),
+            parse_sentry_metadata("ew=="),
             Err(Error::InvalidMetadata(_))
         ));
     }
 
+    #[test]
+    fn test_parse_sentry_metadata_default() {
+        assert!(matches!(
+            parse_sentry_metadata("e30="),
+            Ok(Metadata {
+                attachment_type: AttachmentType::Attachment
+            })
+        ));
+    }
+
     #[test]
     fn test_upload_metadata_absent() {
         assert_eq!(upload_metadata(&HeaderMap::new()).unwrap(), None);