diff --git a/src/services/NotificationService.ts b/src/services/NotificationService.ts
index 2d9651f..3ecaf58 100644
--- a/src/services/NotificationService.ts
+++ b/src/services/NotificationService.ts
@@ -56,6 +56,15 @@ export class NotificationService {
     return this._lastRefreshedTimeMs && Date.now() - this._lastRefreshedTimeMs < thirtyMinutesMs;
   }
 
+  private sendEtaNotificationImmediately({ deviceId, shuttleId, stopId }: ScheduledNotificationData) {
+    // Construct the fetch request
+
+    // Send the fetch request
+
+    // Check whether it was successful
+    // Return the result
+  }
+
   /**
    * Queue a notification to be sent.
    * @param deviceId The device ID to send the notification to.
@@ -63,7 +72,13 @@ export class NotificationService {
    * @param stopId Stop ID of ETA object to check.
    */
   public async scheduleNotification({ deviceId, shuttleId, stopId }: ScheduledNotificationData) {
+    // Associate TupleKey(shuttleId, stopId) with array of device IDs
+    // Refresh the subscriber with the updated array if needed
 
+    // In the subscriber callback:
+    // If the ETA matches, call sendNotification with the necessary parameters
+    // If it was successful, unsubscribe the callback
+    // If it wasn't, leave it until the next ETA update
   }
 
   /**