diff --git a/lib/model/alarm.dart b/lib/model/alarm.dart
index e730c92..1f73729 100644
--- a/lib/model/alarm.dart
+++ b/lib/model/alarm.dart
@@ -2,6 +2,7 @@ import 'location_alarm.dart';
 import 'time_alarm.dart';
 
 abstract class Alarm {
+  String get id;
   String get taskId;
   Map<String, dynamic> toJson();
 
diff --git a/lib/model/location_alarm.dart b/lib/model/location_alarm.dart
index 6fda109..0d8d10a 100644
--- a/lib/model/location_alarm.dart
+++ b/lib/model/location_alarm.dart
@@ -2,6 +2,9 @@ import 'alarm.dart';
 import 'location.dart';
 
 class LocationAlarm implements Alarm {
+  @override
+  final String id;
+
   @override
   final String taskId;
 
@@ -10,6 +13,7 @@ class LocationAlarm implements Alarm {
   final int radiusMeters;
 
   const LocationAlarm({
+    required this.id,
     required this.taskId,
     required this.location,
     required this.radiusMeters,
@@ -17,6 +21,7 @@ class LocationAlarm implements Alarm {
 
   factory LocationAlarm.fromJson(Map<String, dynamic> json) {
     return LocationAlarm(
+      id: json['id'] as String,
       taskId: json['taskId'] as String,
       location: Location.fromJson(json['location'] as Map<String, dynamic>),
       radiusMeters: json['radiusMeters'] as int,
@@ -26,6 +31,7 @@ class LocationAlarm implements Alarm {
   @override
   Map<String, dynamic> toJson() {
     return {
+      'id': id,
       'taskId': taskId,
       'location': location.toJson(),
       'radiusMeters': radiusMeters,
diff --git a/lib/model/time_alarm.dart b/lib/model/time_alarm.dart
index b806543..f7aabc5 100644
--- a/lib/model/time_alarm.dart
+++ b/lib/model/time_alarm.dart
@@ -1,15 +1,23 @@
 import 'alarm.dart';
 
 class TimeAlarm implements Alarm {
+  @override
+  final String id;
+
   @override
   final String taskId;
 
   final DateTime triggerAt;
 
-  const TimeAlarm({required this.taskId, required this.triggerAt});
+  const TimeAlarm({
+    required this.id,
+    required this.taskId,
+    required this.triggerAt,
+  });
 
   factory TimeAlarm.fromJson(Map<String, dynamic> json) {
     return TimeAlarm(
+      id: json['id'] as String,
       taskId: json['taskId'] as String,
       triggerAt: DateTime.parse(json['triggerAt'] as String),
     );
@@ -17,6 +25,10 @@ class TimeAlarm implements Alarm {
 
   @override
   Map<String, dynamic> toJson() {
-    return {'taskId': taskId, 'triggerAt': triggerAt.toIso8601String()};
+    return {
+      'id': id,
+      'taskId': taskId,
+      'triggerAt': triggerAt.toIso8601String(),
+    };
   }
 }