diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3baa42f..e328d58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Added
 
+- New `generic_alert` APNs payload mode: a visible alert whose title and body come from the new `apns.alert_title` / `apns.alert_body` configuration keys (content-free defaults), with no `mutable-content` flag, so deployments can show a notification without shipping a Notification Service Extension. An optional `apns.collapse_id` key sets the `apns-collapse-id` header (any payload mode) so rapid bursts coalesce into a single notification.
 - Optional error and panic reporting to a GlitchTip (Sentry-compatible) instance, enabled by setting `glitchtip.dsn` (or `TRANSPONDER_GLITCHTIP_DSN`). Only Transponder's own `ERROR` events and panics are sent, over a self-contained TLS transport (bundled roots, no system CA store dependency); dependency-crate errors and lower log levels are dropped, and Transponder never logs or panics with secret material.
 
 ### Fixed
diff --git a/README.md b/README.md
index b292d6d..32031a7 100644
--- a/README.md
+++ b/README.md
@@ -141,10 +141,21 @@ environment = "production"
 # Your iOS app's bundle identifier (e.g., "com.example.myapp")
 bundle_id = ""
 
-# APNs payload mode: "silent" or "nse_prototype_alert"
-# Keep production silent. Use nse_prototype_alert only for staging NSE prototype testing.
+# APNs payload mode: "silent", "generic_alert", or "nse_prototype_alert"
+# - silent: background push only (invisible without an NSE or foreground work)
+# - generic_alert: visible alert with the configurable, content-free
+#   alert_title/alert_body below; requires no Notification Service Extension
+# - nse_prototype_alert: staging NSE prototype testing only
 payload_mode = "silent"
 
+# Alert copy for the generic_alert payload mode (keep it content-free)
+alert_title = "New activity"
+alert_body = "You have a new notification"
+
+# Optional apns-collapse-id header value (max 64 bytes); empty disables it.
+# When set, APNs coalesces undelivered notifications with the same id.
+collapse_id = ""
+
 [fcm]
 # Enable FCM for Android push notifications
 enabled = false
diff --git a/config/default.toml b/config/default.toml
index 40b7f8e..c742be9 100644
--- a/config/default.toml
+++ b/config/default.toml
@@ -153,10 +153,25 @@ environment = "production"
 # iOS app bundle identifier
 bundle_id = ""
 
-# APNs payload mode: "silent" or "nse_prototype_alert"
-# Keep production silent. Use nse_prototype_alert only for staging NSE prototype testing.
+# APNs payload mode: "silent", "generic_alert", or "nse_prototype_alert"
+# - silent: background push only; invisible without a Notification Service
+#   Extension or foreground app work.
+# - generic_alert: visible alert with the configurable, content-free
+#   alert_title/alert_body below; requires no Notification Service Extension.
+# - nse_prototype_alert: staging NSE prototype testing only.
 payload_mode = "silent"
 
+# Alert copy for the generic_alert payload mode. Keep these content-free: the
+# transponder never knows message content or sender identity, and the alert
+# must not pretend otherwise.
+alert_title = "New activity"
+alert_body = "You have a new notification"
+
+# Optional apns-collapse-id header value (max 64 bytes); empty disables it.
+# When set, APNs coalesces undelivered notifications with the same id, so a
+# rapid burst surfaces as one notification instead of a stack.
+collapse_id = ""
+
 [fcm]
 # Whether FCM (Android) push notifications are enabled
 enabled = false
diff --git a/config/production.toml.example b/config/production.toml.example
index 9a709fc..71b7c57 100644
--- a/config/production.toml.example
+++ b/config/production.toml.example
@@ -72,7 +72,14 @@ team_id = ""
 private_key_path = "/credentials/AuthKey_XXXXXXXXXX.p8"
 environment = "production"
 bundle_id = ""
+# "silent", "generic_alert" (visible content-free alert, no NSE required),
+# or "nse_prototype_alert" (staging NSE prototype testing only).
 payload_mode = "silent"
+# Alert copy for the generic_alert payload mode (keep it content-free).
+alert_title = "New activity"
+alert_body = "You have a new notification"
+# Optional apns-collapse-id header value (max 64 bytes); empty disables it.
+collapse_id = ""
 
 [fcm]
 enabled = false
diff --git a/src/config.rs b/src/config.rs
index cfc7152..fc08bc6 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -378,6 +378,10 @@ fn default_max_reconnect_attempts() -> u32 {
     10
 }
 
+/// Maximum length in bytes APNs accepts for the `apns-collapse-id` header;
+/// longer values are rejected per-send with a 400 `BadCollapseId`.
+const APNS_COLLAPSE_ID_MAX_BYTES: usize = 64;
+
 /// APNs push notification configuration.
 #[derive(Debug, Clone, Deserialize)]
 #[allow(dead_code)]
@@ -409,6 +413,22 @@ pub struct ApnsConfig {
     /// APNs payload mode.
     #[serde(default)]
     pub payload_mode: ApnsPayloadMode,
+
+    /// Alert title for the `generic_alert` payload mode.
+    #[serde(default = "default_apns_alert_title")]
+    pub alert_title: String,
+
+    /// Alert body for the `generic_alert` payload mode.
+    #[serde(default = "default_apns_alert_body")]
+    pub alert_body: String,
+
+    /// Optional `apns-collapse-id` header value; empty disables the header.
+    ///
+    /// When set, APNs coalesces undelivered notifications carrying the same
+    /// collapse identifier, so a rapid burst surfaces as a single notification
+    /// instead of a stack.
+    #[serde(default)]
+    pub collapse_id: String,
 }
 
 /// APNs gateway environment.
@@ -448,20 +468,26 @@ pub enum ApnsPayloadMode {
 
     /// Alert payload for exercising the iOS Notification Service Extension prototype.
     NsePrototypeAlert,
+
+    /// Visible alert with configurable, content-free title and body
+    /// (`apns.alert_title` / `apns.alert_body`). Requires no Notification
+    /// Service Extension: the payload carries no `mutable-content` flag and
+    /// never reveals message content or sender identity.
+    GenericAlert,
 }
 
 impl ApnsPayloadMode {
     pub(crate) fn push_type(self) -> &'static str {
         match self {
             Self::Silent => "background",
-            Self::NsePrototypeAlert => "alert",
+            Self::NsePrototypeAlert | Self::GenericAlert => "alert",
         }
     }
 
     pub(crate) fn priority(self) -> &'static str {
         match self {
             Self::Silent => "5",
-            Self::NsePrototypeAlert => "10",
+            Self::NsePrototypeAlert | Self::GenericAlert => "10",
         }
     }
 }
@@ -471,6 +497,7 @@ impl std::fmt::Display for ApnsPayloadMode {
         match self {
             Self::Silent => f.write_str("silent"),
             Self::NsePrototypeAlert => f.write_str("nse_prototype_alert"),
+            Self::GenericAlert => f.write_str("generic_alert"),
         }
     }
 }
@@ -479,6 +506,14 @@ fn default_apns_environment() -> ApnsEnvironment {
     ApnsEnvironment::Production
 }
 
+fn default_apns_alert_title() -> String {
+    "New activity".to_string()
+}
+
+fn default_apns_alert_body() -> String {
+    "You have a new notification".to_string()
+}
+
 /// FCM push notification configuration.
 #[derive(Debug, Clone, Deserialize)]
 pub struct FcmConfig {
@@ -897,6 +932,9 @@ fn is_supported_config_key(config_key: &str) -> bool {
                 | "apns.environment"
                 | "apns.bundle_id"
                 | "apns.payload_mode"
+                | "apns.alert_title"
+                | "apns.alert_body"
+                | "apns.collapse_id"
                 | "fcm.enabled"
                 | "fcm.service_account_path"
                 | "fcm.project_id"
@@ -1225,7 +1263,9 @@ impl GlitchtipConfig {
 }
 
 impl ApnsConfig {
-    /// Rejects enabled APNs configuration that is missing required credentials.
+    /// Rejects enabled APNs configuration that is missing required credentials,
+    /// a `generic_alert` mode with nothing to display, or an over-length
+    /// collapse identifier.
     fn validate(&self) -> std::result::Result<(), config::ConfigError> {
         if !self.enabled {
             return Ok(());
@@ -1246,6 +1286,26 @@ impl ApnsConfig {
             }
         }
 
+        // A generic alert with neither a title nor a body renders nothing
+        // visible on the device, defeating the purpose of the mode.
+        if self.payload_mode == ApnsPayloadMode::GenericAlert
+            && self.alert_title.trim().is_empty()
+            && self.alert_body.trim().is_empty()
+        {
+            return Err(config::ConfigError::Message(
+                "apns.alert_title or apns.alert_body must be set when apns.payload_mode = \"generic_alert\"".to_string(),
+            ));
+        }
+
+        // APNs rejects `apns-collapse-id` values over 64 bytes with a 400
+        // BadCollapseId on every send; fail at startup instead.
+        if self.collapse_id.len() > APNS_COLLAPSE_ID_MAX_BYTES {
+            return Err(config::ConfigError::Message(format!(
+                "apns.collapse_id must be at most {APNS_COLLAPSE_ID_MAX_BYTES} bytes, got {}",
+                self.collapse_id.len()
+            )));
+        }
+
         Ok(())
     }
 
@@ -1426,6 +1486,9 @@ mod tests {
             environment: ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         assert!(config.is_production());
@@ -1442,6 +1505,9 @@ mod tests {
             environment: ApnsEnvironment::Sandbox,
             bundle_id: String::new(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         assert!(!config.is_production());
@@ -1963,6 +2029,8 @@ mod tests {
     #[test]
     fn test_apns_config_defaults() {
         assert_eq!(default_apns_environment(), ApnsEnvironment::Production);
+        assert_eq!(default_apns_alert_title(), "New activity");
+        assert_eq!(default_apns_alert_body(), "You have a new notification");
     }
 
     #[test]
@@ -2005,6 +2073,85 @@ mod tests {
         assert!(error.to_string().contains("loud_plaintext"), "{error}");
     }
 
+    #[test]
+    fn test_apns_payload_mode_parses_generic_alert_with_default_copy() {
+        let config_content = r#"
+            [server]
+            private_key = "test"
+
+            [apns]
+            payload_mode = "generic_alert"
+        "#;
+
+        let file = create_temp_config(config_content);
+        let config = load_with_test_env(file.path(), &[]).unwrap();
+
+        assert_eq!(config.apns.payload_mode, ApnsPayloadMode::GenericAlert);
+        assert_eq!(config.apns.alert_title, "New activity");
+        assert_eq!(config.apns.alert_body, "You have a new notification");
+        assert_eq!(config.apns.collapse_id, "");
+    }
+
+    #[test]
+    fn test_apns_generic_alert_custom_copy_and_collapse_id() {
+        let config_content = r#"
+            [server]
+            private_key = "test"
+
+            [apns]
+            payload_mode = "generic_alert"
+            alert_title = "Ping"
+            alert_body = "Something happened"
+            collapse_id = "ping"
+        "#;
+
+        let file = create_temp_config(config_content);
+        let config = load_with_test_env(file.path(), &[]).unwrap();
+
+        assert_eq!(config.apns.alert_title, "Ping");
+        assert_eq!(config.apns.alert_body, "Something happened");
+        assert_eq!(config.apns.collapse_id, "ping");
+    }
+
+    #[test]
+    fn test_apns_generic_alert_without_title_or_body_rejected() {
+        // A generic alert with neither a title nor a body renders nothing
+        // visible, so an explicit double-blank is a startup error.
+        let error = from_test_env(&[
+            ("TRANSPONDER_APNS_ENABLED", "true"),
+            ("TRANSPONDER_APNS_KEY_ID", "KEY123"),
+            ("TRANSPONDER_APNS_TEAM_ID", "TEAM123"),
+            ("TRANSPONDER_APNS_PRIVATE_KEY_PATH", "/keys/apns.p8"),
+            ("TRANSPONDER_APNS_BUNDLE_ID", "com.example.app"),
+            ("TRANSPONDER_APNS_PAYLOAD_MODE", "generic_alert"),
+            ("TRANSPONDER_APNS_ALERT_TITLE", ""),
+            ("TRANSPONDER_APNS_ALERT_BODY", " "),
+        ])
+        .unwrap_err();
+
+        let message = error.to_string();
+        assert!(message.contains("apns.alert_title"), "{message}");
+        assert!(message.contains("generic_alert"), "{message}");
+    }
+
+    #[test]
+    fn test_apns_collapse_id_over_max_length_rejected() {
+        // APNs rejects over-length collapse ids per-send (400 BadCollapseId);
+        // the misconfiguration must fail loudly at startup instead.
+        let long_collapse_id = "x".repeat(APNS_COLLAPSE_ID_MAX_BYTES + 1);
+        let error = from_test_env(&[
+            ("TRANSPONDER_APNS_ENABLED", "true"),
+            ("TRANSPONDER_APNS_KEY_ID", "KEY123"),
+            ("TRANSPONDER_APNS_TEAM_ID", "TEAM123"),
+            ("TRANSPONDER_APNS_PRIVATE_KEY_PATH", "/keys/apns.p8"),
+            ("TRANSPONDER_APNS_BUNDLE_ID", "com.example.app"),
+            ("TRANSPONDER_APNS_COLLAPSE_ID", long_collapse_id.as_str()),
+        ])
+        .unwrap_err();
+
+        assert!(error.to_string().contains("apns.collapse_id"), "{error}");
+    }
+
     #[test]
     fn test_apns_environment_display() {
         assert_eq!(ApnsEnvironment::Production.to_string(), "production");
@@ -2204,6 +2351,9 @@ mod tests {
             environment: ApnsEnvironment::Production,
             bundle_id: String::new(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         assert!(config.is_production());
     }
@@ -2218,6 +2368,9 @@ mod tests {
             environment: ApnsEnvironment::Sandbox,
             bundle_id: String::new(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         assert!(!config.is_production());
     }
diff --git a/src/nostr/events/processor.rs b/src/nostr/events/processor.rs
index 426ce9f..8eb1bed 100644
--- a/src/nostr/events/processor.rs
+++ b/src/nostr/events/processor.rs
@@ -1224,6 +1224,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let metrics = Metrics::new().expect("metrics");
         let push_dispatcher = Arc::new(PushDispatcher::with_metrics(
@@ -1267,6 +1270,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let metrics = Metrics::new().expect("metrics");
         let push_dispatcher = Arc::new(PushDispatcher::with_metrics(
@@ -2526,6 +2532,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let push_dispatcher = Arc::new(PushDispatcher::with_metrics(
             Some(ApnsClient::mock(apns_config, true)),
diff --git a/src/push/apns.rs b/src/push/apns.rs
index cb166fe..0318b33 100644
--- a/src/push/apns.rs
+++ b/src/push/apns.rs
@@ -39,6 +39,7 @@ struct ApnsClaims {
 enum ApnsPayload {
     Silent(ApnsSilentPayload),
     NsePrototypeAlert(ApnsNsePrototypeAlertPayload),
+    GenericAlert(ApnsGenericAlertPayload),
 }
 
 #[derive(Debug, Serialize)]
@@ -62,13 +63,22 @@ impl Default for ApnsPayload {
     }
 }
 
-impl From<ApnsPayloadMode> for ApnsPayload {
-    fn from(mode: ApnsPayloadMode) -> Self {
-        match mode {
+impl ApnsPayload {
+    fn for_config(config: &ApnsConfig) -> Self {
+        match config.payload_mode {
             ApnsPayloadMode::Silent => Self::default(),
             ApnsPayloadMode::NsePrototypeAlert => {
                 Self::NsePrototypeAlert(ApnsNsePrototypeAlertPayload::default())
             }
+            ApnsPayloadMode::GenericAlert => Self::GenericAlert(ApnsGenericAlertPayload {
+                aps: ApnsGenericAlertAps {
+                    alert: ApnsGenericAlert {
+                        title: config.alert_title.clone(),
+                        body: config.alert_body.clone(),
+                    },
+                    sound: "default",
+                },
+            }),
         }
     }
 }
@@ -115,6 +125,31 @@ struct ApnsAlert {
     body: &'static str,
 }
 
+/// Payload for [`ApnsPayloadMode::GenericAlert`]: a visible alert carrying
+/// only the operator-configured title/body — no message content, no sender
+/// identity, and no `mutable-content` flag (no Notification Service Extension
+/// is required to display it).
+#[derive(Debug, Serialize)]
+struct ApnsGenericAlertPayload {
+    aps: ApnsGenericAlertAps,
+}
+
+#[derive(Debug, Serialize)]
+struct ApnsGenericAlertAps {
+    alert: ApnsGenericAlert,
+    sound: &'static str,
+}
+
+#[derive(Debug, Serialize)]
+struct ApnsGenericAlert {
+    /// Omitted from the payload when configured empty (body-only alert).
+    #[serde(skip_serializing_if = "String::is_empty")]
+    title: String,
+    /// Omitted from the payload when configured empty (title-only alert).
+    #[serde(skip_serializing_if = "String::is_empty")]
+    body: String,
+}
+
 fn redacted_device_token_id(_device_token: &str) -> &'static str {
     "<redacted_device_token>"
 }
@@ -127,15 +162,19 @@ fn device_token_url(base_url: &str, device_token: &str) -> Zeroizing<String> {
 struct ApnsRequestParts {
     push_type: &'static str,
     priority: &'static str,
+    /// `apns-collapse-id` header value; `None` leaves the header off.
+    collapse_id: Option<String>,
     payload: ApnsPayload,
 }
 
 impl ApnsRequestParts {
-    fn for_mode(mode: ApnsPayloadMode) -> Self {
+    fn for_config(config: &ApnsConfig) -> Self {
+        let mode = config.payload_mode;
         Self {
             push_type: mode.push_type(),
             priority: mode.priority(),
-            payload: ApnsPayload::from(mode),
+            collapse_id: (!config.collapse_id.is_empty()).then(|| config.collapse_id.clone()),
+            payload: ApnsPayload::for_config(config),
         }
     }
 }
@@ -364,7 +403,7 @@ impl ApnsClient {
         // device-token URL is a zeroizing buffer (issue #126); reqwest still
         // materializes the serialized body/headers into non-zeroized buffers
         // it owns, which is the accepted #126 posture (see build_request).
-        let request_parts = ApnsRequestParts::for_mode(self.config.payload_mode);
+        let request_parts = ApnsRequestParts::for_config(&self.config);
         let url = device_token_url(self.base_url(), device_token.as_str());
 
         debug!(
@@ -411,13 +450,17 @@ impl ApnsClient {
         request_parts: &ApnsRequestParts,
     ) -> reqwest::RequestBuilder {
         let authorization = Zeroizing::new(format!("bearer {auth_token}"));
-        self.http_client
+        let mut request = self
+            .http_client
             .post(url)
             .header("apns-push-type", request_parts.push_type)
             .header("apns-priority", request_parts.priority)
             .header("apns-topic", &self.config.bundle_id)
-            .header("authorization", authorization.as_str())
-            .json(&request_parts.payload)
+            .header("authorization", authorization.as_str());
+        if let Some(collapse_id) = request_parts.collapse_id.as_deref() {
+            request = request.header("apns-collapse-id", collapse_id);
+        }
+        request.json(&request_parts.payload)
     }
 
     async fn handle_response(
@@ -705,6 +748,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         }
     }
 
@@ -760,7 +806,7 @@ mod tests {
         config.payload_mode = ApnsPayloadMode::Silent;
         config.bundle_id = "dev.ipf.whitenoise.staging".to_string();
         let client = ApnsClient::mock(config, false);
-        let request_parts = ApnsRequestParts::for_mode(client.config.payload_mode);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
 
         let request = client
             .build_request(
@@ -793,7 +839,7 @@ mod tests {
         config.payload_mode = ApnsPayloadMode::NsePrototypeAlert;
         config.bundle_id = "dev.ipf.whitenoise.staging".to_string();
         let client = ApnsClient::mock(config, false);
-        let request_parts = ApnsRequestParts::for_mode(client.config.payload_mode);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
 
         let request = client
             .build_request(
@@ -826,6 +872,117 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_generic_alert_mode_builds_alert_headers_and_payload() {
+        let mut config = test_config();
+        config.payload_mode = ApnsPayloadMode::GenericAlert;
+        config.alert_title = "New activity".to_string();
+        config.alert_body = "You have a new notification".to_string();
+        let client = ApnsClient::mock(config, false);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
+
+        let request = client
+            .build_request(
+                "https://api.push.apple.com/3/device/aabbccdd11223344",
+                "test-token",
+                &request_parts,
+            )
+            .build()
+            .unwrap();
+
+        assert_eq!(header_value(&request, "apns-push-type"), "alert");
+        assert_eq!(header_value(&request, "apns-priority"), "10");
+        assert_eq!(header_value(&request, "apns-topic"), "com.example.app");
+        // No collapse id configured: the header must be absent entirely.
+        assert!(request.headers().get("apns-collapse-id").is_none());
+        // The exact payload: configured title/body only — in particular no
+        // `mutable-content` (no NSE required) and no prototype marker field.
+        assert_eq!(
+            request_json(&request),
+            serde_json::json!({
+                "aps": {
+                    "alert": {
+                        "title": "New activity",
+                        "body": "You have a new notification"
+                    },
+                    "sound": "default"
+                }
+            })
+        );
+    }
+
+    #[test]
+    fn test_generic_alert_mode_omits_empty_body_from_alert() {
+        let mut config = test_config();
+        config.payload_mode = ApnsPayloadMode::GenericAlert;
+        config.alert_title = "New activity".to_string();
+        config.alert_body = String::new();
+        let client = ApnsClient::mock(config, false);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
+
+        let request = client
+            .build_request(
+                "https://api.push.apple.com/3/device/aabbccdd11223344",
+                "test-token",
+                &request_parts,
+            )
+            .build()
+            .unwrap();
+
+        // A title-only alert must not carry an empty "body" key.
+        assert_eq!(
+            request_json(&request),
+            serde_json::json!({
+                "aps": {
+                    "alert": {
+                        "title": "New activity"
+                    },
+                    "sound": "default"
+                }
+            })
+        );
+    }
+
+    #[test]
+    fn test_generic_alert_mode_sets_collapse_id_header_when_configured() {
+        let mut config = test_config();
+        config.payload_mode = ApnsPayloadMode::GenericAlert;
+        config.collapse_id = "new-activity".to_string();
+        let client = ApnsClient::mock(config, false);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
+
+        let request = client
+            .build_request(
+                "https://api.push.apple.com/3/device/aabbccdd11223344",
+                "test-token",
+                &request_parts,
+            )
+            .build()
+            .unwrap();
+
+        assert_eq!(header_value(&request, "apns-collapse-id"), "new-activity");
+    }
+
+    #[test]
+    fn test_collapse_id_header_applies_to_any_payload_mode() {
+        let mut config = test_config();
+        config.payload_mode = ApnsPayloadMode::Silent;
+        config.collapse_id = "sync".to_string();
+        let client = ApnsClient::mock(config, false);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
+
+        let request = client
+            .build_request(
+                "https://api.push.apple.com/3/device/aabbccdd11223344",
+                "test-token",
+                &request_parts,
+            )
+            .build()
+            .unwrap();
+
+        assert_eq!(header_value(&request, "apns-collapse-id"), "sync");
+    }
+
     #[tokio::test]
     async fn test_send_once_returns_transport_error_after_connect_retries() {
         let proxy_addr = {
@@ -853,7 +1010,7 @@ mod tests {
             initial_backoff: Duration::from_millis(1),
         };
 
-        let request_parts = ApnsRequestParts::for_mode(client.config.payload_mode);
+        let request_parts = ApnsRequestParts::for_config(&client.config);
         let url = device_token_url(client.config.base_url(), "aabbccdd11223344");
         let result = client
             .send_once_with_transport_retry_config(url.as_str(), &request_parts, &retry_config)
@@ -880,6 +1037,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: String::new(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::new(config).await.unwrap();
@@ -1557,6 +1717,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, true);
@@ -1573,6 +1736,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, true);
@@ -1589,6 +1755,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, true);
@@ -1605,6 +1774,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: String::new(), // Missing
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, true);
@@ -1621,6 +1793,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, false); // No encoding key
@@ -1669,6 +1844,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, false);
@@ -1688,6 +1866,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, true);
@@ -1715,6 +1896,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         // Create a client without an encoding key to test the error case
@@ -1740,6 +1924,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::mock(config, false); // No encoding key
@@ -1767,6 +1954,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::new(config).await.unwrap();
@@ -1783,6 +1973,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let result = ApnsClient::new(config).await;
@@ -1860,6 +2053,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         // Client without encoding key - should fail when trying to generate
@@ -1895,6 +2091,9 @@ OF/2NxApJCzGCEDdfSp6VQO30hyhRANCAAQRWz+jn65BtOMvdyHKcvjBeBSDZH2r
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::new(config).await.unwrap();
@@ -1926,6 +2125,9 @@ OF/2NxApJCzGCEDdfSp6VQO30hyhRANCAAQRWz+jn65BtOMvdyHKcvjBeBSDZH2r
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let metrics = Metrics::new().unwrap();
@@ -2041,6 +2243,9 @@ OF/2NxApJCzGCEDdfSp6VQO30hyhRANCAAQRWz+jn65BtOMvdyHKcvjBeBSDZH2r
             environment: crate::config::ApnsEnvironment::Production,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let client = ApnsClient::new(config).await.unwrap();
diff --git a/src/push/dispatcher/mod.rs b/src/push/dispatcher/mod.rs
index 2170fdc..19213fd 100644
--- a/src/push/dispatcher/mod.rs
+++ b/src/push/dispatcher/mod.rs
@@ -1063,6 +1063,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_only = PushDispatcher::new(Some(ApnsClient::mock(apns_config, true)), None);
         assert!(apns_only.accepts(Platform::Apns));
@@ -1131,6 +1134,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let apns_client = ApnsClient::mock(config, true);
@@ -1198,6 +1204,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
         let dispatcher = PushDispatcher::new(Some(apns_client), None);
@@ -1249,6 +1258,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
 
@@ -1320,6 +1332,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let metrics = Metrics::new().unwrap();
@@ -1364,6 +1379,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
 
@@ -1395,6 +1413,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: String::new(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, false);
         let dispatcher = PushDispatcher::new(Some(apns_client), None);
@@ -1445,6 +1466,9 @@ mod tests {
                     environment: crate::config::ApnsEnvironment::Sandbox,
                     bundle_id: "com.example.app".to_string(),
                     payload_mode: Default::default(),
+                    alert_title: String::new(),
+                    alert_body: String::new(),
+                    collapse_id: String::new(),
                 },
                 true,
             )),
@@ -1604,6 +1628,9 @@ mod tests {
                     environment: crate::config::ApnsEnvironment::Sandbox,
                     bundle_id: "com.example.app".to_string(),
                     payload_mode: Default::default(),
+                    alert_title: String::new(),
+                    alert_body: String::new(),
+                    collapse_id: String::new(),
                 },
                 true,
             )),
@@ -1643,6 +1670,9 @@ mod tests {
                     environment: crate::config::ApnsEnvironment::Sandbox,
                     bundle_id: "com.example.app".to_string(),
                     payload_mode: Default::default(),
+                    alert_title: String::new(),
+                    alert_body: String::new(),
+                    collapse_id: String::new(),
                 },
                 true,
             )),
@@ -1700,6 +1730,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
         let dispatcher = PushDispatcher::new(Some(apns_client), None);
@@ -1722,6 +1755,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let dispatcher = Arc::new(PushDispatcher::new(
             Some(ApnsClient::mock(apns_config, true)),
@@ -1769,6 +1805,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let dispatcher = Arc::new(PushDispatcher::new(
             Some(ApnsClient::mock(apns_config, true)),
@@ -1836,6 +1875,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
         let metrics = Metrics::new().unwrap();
@@ -1892,6 +1934,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
 
         let metrics = Metrics::new().unwrap();
@@ -2094,6 +2139,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let mut client = ApnsClient::mock(apns_config, true);
         client.test_base_url = Some(mock_server.uri());
diff --git a/src/server/health.rs b/src/server/health.rs
index d6de2f0..e2dec84 100644
--- a/src/server/health.rs
+++ b/src/server/health.rs
@@ -777,6 +777,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
         let push_dispatcher = Arc::new(PushDispatcher::new(Some(apns_client), None));
@@ -847,6 +850,9 @@ mod tests {
             environment: crate::config::ApnsEnvironment::Sandbox,
             bundle_id: "com.example.app".to_string(),
             payload_mode: Default::default(),
+            alert_title: String::new(),
+            alert_body: String::new(),
+            collapse_id: String::new(),
         };
         let apns_client = ApnsClient::mock(apns_config, true);
         let push_dispatcher = Arc::new(PushDispatcher::new(Some(apns_client), None));