diff --git a/packages/backend/src/server/api/common/read-messaging-message.ts b/packages/backend/src/server/api/common/read-messaging-message.ts
index e8706fe86a..d4d04c6b91 100644
--- a/packages/backend/src/server/api/common/read-messaging-message.ts
+++ b/packages/backend/src/server/api/common/read-messaging-message.ts
@@ -68,12 +68,10 @@ export async function readUserMessagingMessage(
 		await sendPushNotification(userId, PushNotificationKind.ReadAllChats, {});
 	} else {
 		// そのユーザーとのメッセージで未読がなければイベント発行
-		const hasUnread = await MessagingMessages.exists({
-			where: {
-				userId: otherpartyId,
-				recipientId: userId,
-				isRead: false,
-			},
+		const hasUnread = await MessagingMessages.existsBy({
+			userId: otherpartyId,
+			recipientId: userId,
+			isRead: false,
 		});
 
 		if (!hasUnread) {
diff --git a/packages/backend/src/server/api/endpoints/admin/promo/create.ts b/packages/backend/src/server/api/endpoints/admin/promo/create.ts
index 55038fc89b..ffbab9367b 100644
--- a/packages/backend/src/server/api/endpoints/admin/promo/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/promo/create.ts
@@ -40,9 +40,9 @@ export default define(meta, paramDef, async (ps, user) => {
 		throw err;
 	});
 
-	const exist = await PromoNotes.exist({ where: { noteId: note.id } });
+	const exists = await PromoNotes.existsBy({ noteId: note.id });
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyPromoted);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/auth/accept.ts b/packages/backend/src/server/api/endpoints/auth/accept.ts
index 3bdc9e18b5..ab8b0cd148 100644
--- a/packages/backend/src/server/api/endpoints/auth/accept.ts
+++ b/packages/backend/src/server/api/endpoints/auth/accept.ts
@@ -2,7 +2,7 @@ import * as crypto from "node:crypto";
 import define from "@/server/api/define.js";
 import { ApiError } from "@/server/api/error.js";
 import { AuthSessions, AccessTokens, Apps } from "@/models/index.js";
-import { genId, generateSecureRandomString } from "backend-rs";
+import { genIdAt, generateSecureRandomString } from "backend-rs";
 
 export const meta = {
 	tags: ["auth"],
@@ -40,14 +40,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	const accessToken = generateSecureRandomString(32);
 
 	// Fetch exist access token
-	const exist = await AccessTokens.exists({
-		where: {
-			appId: session.appId,
-			userId: user.id,
-		},
+	const exists = await AccessTokens.existsBy({
+		appId: session.appId,
+		userId: user.id,
 	});
 
-	if (!exist) {
+	if (!exists) {
 		// Lookup app
 		const app = await Apps.findOneByOrFail({ id: session.appId });
 
@@ -60,7 +58,7 @@ export default define(meta, paramDef, async (ps, user) => {
 
 		// Insert access token doc
 		await AccessTokens.insert({
-			id: genId(),
+			id: genIdAt(now),
 			createdAt: now,
 			lastUsedAt: now,
 			appId: session.appId,
diff --git a/packages/backend/src/server/api/endpoints/blocking/create.ts b/packages/backend/src/server/api/endpoints/blocking/create.ts
index 85ac239f35..a2c58aea50 100644
--- a/packages/backend/src/server/api/endpoints/blocking/create.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/create.ts
@@ -69,14 +69,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already blocking
-	const exist = await Blockings.exist({
-		where: {
-			blockerId: blocker.id,
-			blockeeId: blockee.id,
-		},
+	const exists = await Blockings.existsBy({
+		blockerId: blocker.id,
+		blockeeId: blockee.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyBlocking);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/blocking/delete.ts b/packages/backend/src/server/api/endpoints/blocking/delete.ts
index ce1a717d13..bdd930f0df 100644
--- a/packages/backend/src/server/api/endpoints/blocking/delete.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/delete.ts
@@ -69,14 +69,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not blocking
-	const exist = await Blockings.exist({
-		where: {
-			blockerId: blocker.id,
-			blockeeId: blockee.id,
-		},
+	const exists = await Blockings.existsBy({
+		blockerId: blocker.id,
+		blockeeId: blockee.id,
 	});
 
-	if (!exist) {
+	if (!exists) {
 		throw new ApiError(meta.errors.notBlocking);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/clips/add-note.ts b/packages/backend/src/server/api/endpoints/clips/add-note.ts
index 2c34db5603..305e977681 100644
--- a/packages/backend/src/server/api/endpoints/clips/add-note.ts
+++ b/packages/backend/src/server/api/endpoints/clips/add-note.ts
@@ -57,14 +57,12 @@ export default define(meta, paramDef, async (ps, user) => {
 		throw err;
 	});
 
-	const exist = await ClipNotes.exist({
-		where: {
-			noteId: note.id,
-			clipId: clip.id,
-		},
+	const exists = await ClipNotes.existsBy({
+		noteId: note.id,
+		clipId: clip.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyClipped);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts b/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
index 2ce9fa4700..cc98865fb4 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
@@ -26,12 +26,8 @@ export const paramDef = {
 } as const;
 
 export default define(meta, paramDef, async (ps, user) => {
-	const exist = await DriveFiles.exist({
-		where: {
-			md5: ps.md5,
-			userId: user.id,
-		},
+	return await DriveFiles.existsBy({
+		md5: ps.md5,
+		userId: user.id,
 	});
-
-	return exist;
 });
diff --git a/packages/backend/src/server/api/endpoints/following/create.ts b/packages/backend/src/server/api/endpoints/following/create.ts
index 956dc14f6f..29d5d6c84c 100644
--- a/packages/backend/src/server/api/endpoints/following/create.ts
+++ b/packages/backend/src/server/api/endpoints/following/create.ts
@@ -82,14 +82,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already following
-	const exist = await Followings.exist({
-		where: {
-			followerId: follower.id,
-			followeeId: followee.id,
-		},
+	const exists = await Followings.existsBy({
+		followerId: follower.id,
+		followeeId: followee.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyFollowing);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/following/delete.ts b/packages/backend/src/server/api/endpoints/following/delete.ts
index 740ef5fd93..95fd254f48 100644
--- a/packages/backend/src/server/api/endpoints/following/delete.ts
+++ b/packages/backend/src/server/api/endpoints/following/delete.ts
@@ -69,14 +69,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not following
-	const exist = await Followings.exist({
-		where: {
-			followerId: follower.id,
-			followeeId: followee.id,
-		},
+	const exists = await Followings.existsBy({
+		followerId: follower.id,
+		followeeId: followee.id,
 	});
 
-	if (!exist) {
+	if (!exists) {
 		throw new ApiError(meta.errors.notFollowing);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/following/invalidate.ts b/packages/backend/src/server/api/endpoints/following/invalidate.ts
index 682e7d963b..1baa8df64f 100644
--- a/packages/backend/src/server/api/endpoints/following/invalidate.ts
+++ b/packages/backend/src/server/api/endpoints/following/invalidate.ts
@@ -69,14 +69,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not following
-	const exist = await Followings.exist({
-		where: {
-			followerId: follower.id,
-			followeeId: followee.id,
-		},
+	const exists = await Followings.existsBy({
+		followerId: follower.id,
+		followeeId: followee.id,
 	});
 
-	if (!exist) {
+	if (!exists) {
 		throw new ApiError(meta.errors.notFollowing);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/like.ts b/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
index 2b1e2aa01b..bd31da4900 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
@@ -40,14 +40,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	}
 
 	// if already liked
-	const exist = await GalleryLikes.exist({
-		where: {
-			postId: post.id,
-			userId: user.id,
-		},
+	const exists = await GalleryLikes.existsBy({
+		postId: post.id,
+		userId: user.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyLiked);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/i/read-announcement.ts b/packages/backend/src/server/api/endpoints/i/read-announcement.ts
index 65b24c6889..7981292031 100644
--- a/packages/backend/src/server/api/endpoints/i/read-announcement.ts
+++ b/packages/backend/src/server/api/endpoints/i/read-announcement.ts
@@ -30,20 +30,18 @@ export const paramDef = {
 
 export default define(meta, paramDef, async (ps, user) => {
 	// Check if announcement exists
-	const exist = await Announcements.exist({
-		where: { id: ps.announcementId },
+	const exists = await Announcements.existsBy({
+		id: ps.announcementId,
 	});
 
-	if (!exist) {
+	if (!exists) {
 		throw new ApiError(meta.errors.noSuchAnnouncement);
 	}
 
 	// Check if already read
-	const read = await AnnouncementReads.exist({
-		where: {
-			announcementId: ps.announcementId,
-			userId: user.id,
-		},
+	const read = await AnnouncementReads.existsBy({
+		announcementId: ps.announcementId,
+		userId: user.id,
 	});
 
 	if (read) {
diff --git a/packages/backend/src/server/api/endpoints/i/revoke-token.ts b/packages/backend/src/server/api/endpoints/i/revoke-token.ts
index f3e8116944..e38b330742 100644
--- a/packages/backend/src/server/api/endpoints/i/revoke-token.ts
+++ b/packages/backend/src/server/api/endpoints/i/revoke-token.ts
@@ -17,9 +17,9 @@ export const paramDef = {
 } as const;
 
 export default define(meta, paramDef, async (ps, user) => {
-	const exist = await AccessTokens.exist({ where: { id: ps.tokenId } });
+	const exists = await AccessTokens.existsBy({ id: ps.tokenId });
 
-	if (exist) {
+	if (exists) {
 		await AccessTokens.delete({
 			id: ps.tokenId,
 			userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/mute/create.ts b/packages/backend/src/server/api/endpoints/mute/create.ts
index 85548d4014..c8d6744b1b 100644
--- a/packages/backend/src/server/api/endpoints/mute/create.ts
+++ b/packages/backend/src/server/api/endpoints/mute/create.ts
@@ -64,14 +64,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already muting
-	const exist = await Mutings.exist({
-		where: {
-			muterId: muter.id,
-			muteeId: mutee.id,
-		},
+	const exists = await Mutings.existsBy({
+		muterId: muter.id,
+		muteeId: mutee.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyMuting);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/notes/create.ts b/packages/backend/src/server/api/endpoints/notes/create.ts
index 55fb47b1ad..ae5cdc2aab 100644
--- a/packages/backend/src/server/api/endpoints/notes/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/create.ts
@@ -233,11 +233,9 @@ export default define(meta, paramDef, async (ps, user) => {
 
 		// Check blocking
 		if (renote.userId !== user.id) {
-			const isBlocked = await Blockings.exists({
-				where: {
-					blockerId: renote.userId,
-					blockeeId: user.id,
-				},
+			const isBlocked = await Blockings.existsBy({
+				blockerId: renote.userId,
+				blockeeId: user.id,
 			});
 			if (isBlocked) {
 				throw new ApiError(meta.errors.youHaveBeenBlocked);
@@ -260,11 +258,9 @@ export default define(meta, paramDef, async (ps, user) => {
 
 		// Check blocking
 		if (reply.userId !== user.id) {
-			const isBlocked = await Blockings.exists({
-				where: {
-					blockerId: reply.userId,
-					blockeeId: user.id,
-				},
+			const isBlocked = await Blockings.existsBy({
+				blockerId: reply.userId,
+				blockeeId: user.id,
 			});
 			if (isBlocked) {
 				throw new ApiError(meta.errors.youHaveBeenBlocked);
diff --git a/packages/backend/src/server/api/endpoints/notes/favorites/create.ts b/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
index 48bea4496f..37df0f4023 100644
--- a/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
@@ -43,14 +43,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// if already favorited
-	const exist = await NoteFavorites.exist({
-		where: {
-			noteId: note.id,
-			userId: user.id,
-		},
+	const exists = await NoteFavorites.existsBy({
+		noteId: note.id,
+		userId: user.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyFavorited);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/pages/like.ts b/packages/backend/src/server/api/endpoints/pages/like.ts
index e6c7f1fbb5..e8db1788db 100644
--- a/packages/backend/src/server/api/endpoints/pages/like.ts
+++ b/packages/backend/src/server/api/endpoints/pages/like.ts
@@ -40,14 +40,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	}
 
 	// if already liked
-	const exist = await PageLikes.exist({
-		where: {
-			pageId: page.id,
-			userId: user.id,
-		},
+	const exists = await PageLikes.existsBy({
+		pageId: page.id,
+		userId: user.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyLiked);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/promo/read.ts b/packages/backend/src/server/api/endpoints/promo/read.ts
index 362e26c463..0190c5a9a0 100644
--- a/packages/backend/src/server/api/endpoints/promo/read.ts
+++ b/packages/backend/src/server/api/endpoints/promo/read.ts
@@ -33,14 +33,12 @@ export default define(meta, paramDef, async (ps, user) => {
 		throw err;
 	});
 
-	const exist = await PromoReads.exist({
-		where: {
-			noteId: note.id,
-			userId: user.id,
-		},
+	const exists = await PromoReads.existsBy({
+		noteId: note.id,
+		userId: user.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		return;
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/renote-mute/create.ts b/packages/backend/src/server/api/endpoints/renote-mute/create.ts
index b69f1e086b..3b2c22a98a 100644
--- a/packages/backend/src/server/api/endpoints/renote-mute/create.ts
+++ b/packages/backend/src/server/api/endpoints/renote-mute/create.ts
@@ -47,14 +47,12 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already muting
-	const exist = await RenoteMutings.exist({
-		where: {
-			muterId: muter.id,
-			muteeId: mutee.id,
-		},
+	const exists = await RenoteMutings.existsBy({
+		muterId: muter.id,
+		muteeId: mutee.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyMuting);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/users/followers.ts b/packages/backend/src/server/api/endpoints/users/followers.ts
index ab1cac2442..26d80adcd5 100644
--- a/packages/backend/src/server/api/endpoints/users/followers.ts
+++ b/packages/backend/src/server/api/endpoints/users/followers.ts
@@ -103,11 +103,9 @@ export default define(meta, paramDef, async (ps, me) => {
 		if (me == null) {
 			throw new ApiError(meta.errors.forbidden);
 		} else if (me.id !== user.id) {
-			const isFollowed = await Followings.exist({
-				where: {
-					followeeId: user.id,
-					followerId: me.id,
-				},
+			const isFollowed = await Followings.existsBy({
+				followeeId: user.id,
+				followerId: me.id,
 			});
 			if (!isFollowed) {
 				throw new ApiError(meta.errors.nullFollowers);
diff --git a/packages/backend/src/server/api/endpoints/users/following.ts b/packages/backend/src/server/api/endpoints/users/following.ts
index 05ab3602b0..7d5d4d65a4 100644
--- a/packages/backend/src/server/api/endpoints/users/following.ts
+++ b/packages/backend/src/server/api/endpoints/users/following.ts
@@ -102,11 +102,9 @@ export default define(meta, paramDef, async (ps, me) => {
 		if (me == null) {
 			throw new ApiError(meta.errors.forbidden);
 		} else if (me.id !== user.id) {
-			const isFollowing = await Followings.exist({
-				where: {
-					followeeId: user.id,
-					followerId: me.id,
-				},
+			const isFollowing = await Followings.existsBy({
+				followeeId: user.id,
+				followerId: me.id,
 			});
 			if (!isFollowing) {
 				throw new ApiError(meta.errors.cannot_find);
diff --git a/packages/backend/src/server/api/endpoints/users/lists/push.ts b/packages/backend/src/server/api/endpoints/users/lists/push.ts
index 8dd4442d00..9efb3b5982 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/push.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/push.ts
@@ -70,25 +70,21 @@ export default define(meta, paramDef, async (ps, me) => {
 
 	// Check blocking
 	if (user.id !== me.id) {
-		const isBlocked = await Blockings.exist({
-			where: {
-				blockerId: user.id,
-				blockeeId: me.id,
-			},
+		const isBlocked = await Blockings.existsBy({
+			blockerId: user.id,
+			blockeeId: me.id,
 		});
 		if (isBlocked) {
 			throw new ApiError(meta.errors.youHaveBeenBlocked);
 		}
 	}
 
-	const exist = await UserListJoinings.exist({
-		where: {
-			userListId: ps.listId,
-			userId: user.id,
-		},
+	const exists = await UserListJoinings.existsBy({
+		userListId: ps.listId,
+		userId: user.id,
 	});
 
-	if (exist) {
+	if (exists) {
 		throw new ApiError(meta.errors.alreadyAdded);
 	}
 
diff --git a/packages/backend/src/server/api/stream/channels/user-list.ts b/packages/backend/src/server/api/stream/channels/user-list.ts
index 2722a6610a..d8d2fbb378 100644
--- a/packages/backend/src/server/api/stream/channels/user-list.ts
+++ b/packages/backend/src/server/api/stream/channels/user-list.ts
@@ -22,13 +22,11 @@ export default class extends Channel {
 		this.listId = params.listId as string;
 
 		// Check existence and owner
-		const exist = await UserLists.exists({
-			where: {
-				id: this.listId,
-				userId: this.user!.id,
-			},
+		const exists = await UserLists.existsBy({
+			id: this.listId,
+			userId: this.user!.id,
 		});
-		if (!exist) return;
+		if (!exists) return;
 
 		// Subscribe stream
 		this.subscriber.on(`userListStream:${this.listId}`, this.send);
diff --git a/packages/backend/src/services/create-notification.ts b/packages/backend/src/services/create-notification.ts
index 55fa6819c1..4a633dff2e 100644
--- a/packages/backend/src/services/create-notification.ts
+++ b/packages/backend/src/services/create-notification.ts
@@ -39,8 +39,9 @@ export async function createNotification(
 			(notifier.isSilenced ||
 				(Users.isRemoteUser(notifier) &&
 					(await isSilencedServer(notifier.host)))) &&
-			!(await Followings.exists({
-				where: { followerId: notifieeId, followeeId: data.notifierId },
+			!(await Followings.existsBy({
+				followerId: notifieeId,
+				followeeId: data.notifierId,
 			}))
 		)
 			return null;
diff --git a/packages/backend/src/services/note/unread.ts b/packages/backend/src/services/note/unread.ts
index e00dcd07ac..d52ac46d4d 100644
--- a/packages/backend/src/services/note/unread.ts
+++ b/packages/backend/src/services/note/unread.ts
@@ -42,9 +42,9 @@ export async function insertNoteUnread(
 
 	// 2秒経っても既読にならなかったら「未読の投稿がありますよ」イベントを発行する
 	setTimeout(async () => {
-		const exist = await NoteUnreads.exist({ where: { id: unread.id } });
+		const exists = await NoteUnreads.existsBy({ id: unread.id });
 
-		if (!exist) return;
+		if (!exists) return;
 
 		if (params.isMentioned) {
 			publishMainStream(userId, "unreadMention", note.id);