diff --git a/packages/backend/src/server/api/mastodon/MastodonConverters.ts b/packages/backend/src/server/api/mastodon/MastodonConverters.ts
index 7a1387e4aa..0e8ce5a2a7 100644
--- a/packages/backend/src/server/api/mastodon/MastodonConverters.ts
+++ b/packages/backend/src/server/api/mastodon/MastodonConverters.ts
@@ -6,6 +6,8 @@
 import { Inject, Injectable } from '@nestjs/common';
 import { Entity } from 'megalodon';
 import mfm from '@transfem-org/sfm-js';
+import { MastodonNotificationType } from 'megalodon/lib/src/mastodon/notification.js';
+import { NotificationType } from 'megalodon/lib/src/notification.js';
 import { DI } from '@/di-symbols.js';
 import { MfmService } from '@/core/MfmService.js';
 import type { Config } from '@/config.js';
@@ -355,27 +357,9 @@ export class MastodonConverters {
 			created_at: notification.created_at,
 			id: notification.id,
 			status: notification.status ? await this.convertStatus(notification.status, me) : undefined,
-			type: notification.type,
+			type: convertNotificationType(notification.type as NotificationType),
 		};
 	}
-
-	// public convertEmoji(emoji: string): MastodonEntity.Emoji {
-	// 	const reaction: MastodonEntity.Reaction = {
-	// 		name: emoji,
-	// 		count: 1,
-	// 	};
-	//
-	// 	if (emoji.startsWith(':')) {
-	// 		const [, name] = emoji.match(/^:([^@:]+(?:@[^@:]+)?):$/) ?? [];
-	// 		if (name) {
-	// 			const url = `${this.config.url}/emoji/${name}.webp`;
-	// 			reaction.url = url;
-	// 			reaction.static_url = url;
-	// 		}
-	// 	}
-	//
-	// 	return reaction;
-	// }
 }
 
 function simpleConvert<T>(data: T): T {
@@ -383,6 +367,19 @@ function simpleConvert<T>(data: T): T {
 	return Object.assign({}, data);
 }
 
+function convertNotificationType(type: NotificationType): MastodonNotificationType {
+	switch (type) {
+		case 'emoji_reaction': return 'reaction';
+		case 'poll_vote':
+		case 'poll_expired':
+			return 'poll';
+		// Not supported by mastodon
+		case 'move':
+			return type as MastodonNotificationType;
+		default: return type;
+	}
+}
+
 export function convertAnnouncement(announcement: Entity.Announcement): MastodonEntity.Announcement {
 	return {
 		...announcement,
diff --git a/packages/megalodon/src/index.ts b/packages/megalodon/src/index.ts
index 621f007ccf..7a4f10ab02 100644
--- a/packages/megalodon/src/index.ts
+++ b/packages/megalodon/src/index.ts
@@ -6,7 +6,7 @@ import { MegalodonInterface, WebSocketInterface } from './megalodon'
 import { detector } from './detector'
 import Misskey from './misskey'
 import Entity from './entity'
-import NotificationType from './notification'
+import * as NotificationType from './notification'
 import FilterContext from './filter_context'
 import Converter from './converter'
 import MastodonEntity from './mastodon/entity';
diff --git a/packages/megalodon/src/mastodon/notification.ts b/packages/megalodon/src/mastodon/notification.ts
new file mode 100644
index 0000000000..9c51f9698d
--- /dev/null
+++ b/packages/megalodon/src/mastodon/notification.ts
@@ -0,0 +1,33 @@
+export const Mention = 'mention' as const;
+export const Reblog = 'reblog' as const;
+export const Favourite = 'favourite' as const;
+export const Follow = 'follow' as const;
+export const Poll = 'poll' as const;
+export const FollowRequest = 'follow_request' as const;
+export const Status = 'status' as const;
+export const Update = 'update' as const;
+export const AdminSignup = 'admin.sign_up' as const;
+export const AdminReport = 'admin.report' as const;
+export const Reaction = 'reaction' as const;
+export const ModerationWarning = 'moderation_warning' as const;
+export const SeveredRelationships = 'severed_relationships' as const;
+export const AnnualReport = 'annual_report' as const;
+
+export const mastodonNotificationTypes = [
+	Mention,
+	Reblog,
+	Favourite,
+	Follow,
+	Poll,
+	FollowRequest,
+	Status,
+	Update,
+	AdminSignup,
+	AdminReport,
+	Reaction,
+	ModerationWarning,
+	SeveredRelationships,
+	AnnualReport,
+];
+
+export type MastodonNotificationType = typeof mastodonNotificationTypes[number];
diff --git a/packages/megalodon/src/misskey/api_client.ts b/packages/megalodon/src/misskey/api_client.ts
index 4c975c4dfa..6dfa59f132 100644
--- a/packages/megalodon/src/misskey/api_client.ts
+++ b/packages/megalodon/src/misskey/api_client.ts
@@ -9,7 +9,8 @@ import MisskeyEntity from './entity'
 import MegalodonEntity from '../entity'
 import WebSocket from './web_socket'
 import MisskeyNotificationType from './notification'
-import NotificationType, { UnknownNotificationTypeError } from '../notification'
+import * as NotificationType from '../notification'
+import { UnknownNotificationTypeError } from '../notification';
 
 namespace MisskeyAPI {
   export namespace Entity {
diff --git a/packages/megalodon/src/notification.ts b/packages/megalodon/src/notification.ts
index 7c08c5d47f..846d79c6d7 100644
--- a/packages/megalodon/src/notification.ts
+++ b/packages/megalodon/src/notification.ts
@@ -1,20 +1,16 @@
-import Entity from './entity'
-
-namespace NotificationType {
-  export const Follow: Entity.NotificationType = 'follow'
-  export const Favourite: Entity.NotificationType = 'favourite'
-  export const Reblog: Entity.NotificationType = 'reblog'
-  export const Mention: Entity.NotificationType = 'mention'
-  export const EmojiReaction: Entity.NotificationType = 'emoji_reaction'
-  export const FollowRequest: Entity.NotificationType = 'follow_request'
-  export const Status: Entity.NotificationType = 'status'
-  export const PollVote: Entity.NotificationType = 'poll_vote'
-  export const PollExpired: Entity.NotificationType = 'poll_expired'
-  export const Update: Entity.NotificationType = 'update'
-  export const Move: Entity.NotificationType = 'move'
-  export const AdminSignup: Entity.NotificationType = 'admin.sign_up'
-  export const AdminReport: Entity.NotificationType = 'admin.report'
-}
+export const Follow = 'follow' as const;
+export const Favourite = 'favourite' as const;
+export const Reblog = 'reblog' as const;
+export const Mention = 'mention' as const;
+export const EmojiReaction = 'emoji_reaction' as const;
+export const FollowRequest = 'follow_request' as const;
+export const Status = 'status' as const;
+export const PollVote = 'poll_vote' as const;
+export const PollExpired = 'poll_expired' as const;
+export const Update = 'update' as const;
+export const Move = 'move' as const;
+export const AdminSignup = 'admin.sign_up' as const;
+export const AdminReport = 'admin.report' as const;
 
 export class UnknownNotificationTypeError extends Error {
   constructor() {
@@ -23,4 +19,20 @@ export class UnknownNotificationTypeError extends Error {
   }
 }
 
-export default NotificationType
+export const notificationTypes = [
+	Follow,
+	Favourite,
+	Reblog,
+	Mention,
+	EmojiReaction,
+	FollowRequest,
+	Status,
+	PollVote,
+	PollExpired,
+	Update,
+	Move,
+	AdminSignup,
+	AdminReport,
+];
+
+export type NotificationType = typeof notificationTypes[number];
diff --git a/packages/megalodon/test/integration/misskey.spec.ts b/packages/megalodon/test/integration/misskey.spec.ts
index ed3b9a40f2..84d85498d6 100644
--- a/packages/megalodon/test/integration/misskey.spec.ts
+++ b/packages/megalodon/test/integration/misskey.spec.ts
@@ -1,7 +1,7 @@
 import MisskeyEntity from '@/misskey/entity'
 import MisskeyNotificationType from '@/misskey/notification'
 import Misskey from '@/misskey'
-import MegalodonNotificationType from '@/notification'
+import * as MegalodonNotificationType from '@/notification'
 import axios, { AxiosHeaders, AxiosResponse, InternalAxiosRequestConfig } from 'axios'
 
 jest.mock('axios')
diff --git a/packages/megalodon/test/unit/misskey/api_client.spec.ts b/packages/megalodon/test/unit/misskey/api_client.spec.ts
index 38039385cb..ab40bab6c2 100644
--- a/packages/megalodon/test/unit/misskey/api_client.spec.ts
+++ b/packages/megalodon/test/unit/misskey/api_client.spec.ts
@@ -1,7 +1,7 @@
 import MisskeyAPI from '@/misskey/api_client'
 import MegalodonEntity from '@/entity'
 import MisskeyEntity from '@/misskey/entity'
-import MegalodonNotificationType from '@/notification'
+import * as MegalodonNotificationType from '@/notification'
 import MisskeyNotificationType from '@/misskey/notification'
 
 const user: MisskeyEntity.User = {