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 a6d1f3519..00244a777 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.findOneBy({ noteId: note.id });
+	const exist = await PromoNotes.exist({ where: { noteId: note.id } });
 
-	if (exist != null) {
+	if (exist) {
 		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 35565e256..8e6ad6527 100644
--- a/packages/backend/src/server/api/endpoints/auth/accept.ts
+++ b/packages/backend/src/server/api/endpoints/auth/accept.ts
@@ -41,12 +41,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	const accessToken = secureRndstr(32, true);
 
 	// Fetch exist access token
-	const exist = await AccessTokens.findOneBy({
-		appId: session.appId,
-		userId: user.id,
+	const exist = await AccessTokens.exist({
+		where: {
+			appId: session.appId,
+			userId: user.id,
+		},
 	});
 
-	if (exist == null) {
+	if (!exist) {
 		// Lookup app
 		const app = await Apps.findOneByOrFail({ id: 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 4bd58d5ef..f00a2923d 100644
--- a/packages/backend/src/server/api/endpoints/blocking/create.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/create.ts
@@ -69,12 +69,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already blocking
-	const exist = await Blockings.findOneBy({
-		blockerId: blocker.id,
-		blockeeId: blockee.id,
+	const exist = await Blockings.exist({
+		where: {
+			blockerId: blocker.id,
+			blockeeId: blockee.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 6c4ca2775..037d5af22 100644
--- a/packages/backend/src/server/api/endpoints/blocking/delete.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/delete.ts
@@ -69,12 +69,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not blocking
-	const exist = await Blockings.findOneBy({
-		blockerId: blocker.id,
-		blockeeId: blockee.id,
+	const exist = await Blockings.exist({
+		where: {
+			blockerId: blocker.id,
+			blockeeId: blockee.id,
+		},
 	});
 
-	if (exist == null) {
+	if (!exist) {
 		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 b9d6b54c9..416af6faa 100644
--- a/packages/backend/src/server/api/endpoints/clips/add-note.ts
+++ b/packages/backend/src/server/api/endpoints/clips/add-note.ts
@@ -57,12 +57,14 @@ export default define(meta, paramDef, async (ps, user) => {
 		throw err;
 	});
 
-	const exist = await ClipNotes.findOneBy({
-		noteId: note.id,
-		clipId: clip.id,
+	const exist = await ClipNotes.exist({
+		where: {
+			noteId: note.id,
+			clipId: clip.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 df8968520..e26da30eb 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
@@ -26,10 +26,12 @@ export const paramDef = {
 } as const;
 
 export default define(meta, paramDef, async (ps, user) => {
-	const file = await DriveFiles.findOneBy({
-		md5: ps.md5,
-		userId: user.id,
+	const exist = await DriveFiles.exist({
+		where: {
+			md5: ps.md5,
+			userId: user.id,
+		},
 	});
 
-	return file != null;
+	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 e617c1ffb..48ae6ae7a 100644
--- a/packages/backend/src/server/api/endpoints/following/create.ts
+++ b/packages/backend/src/server/api/endpoints/following/create.ts
@@ -82,12 +82,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already following
-	const exist = await Followings.findOneBy({
-		followerId: follower.id,
-		followeeId: followee.id,
+	const exist = await Followings.exist({
+		where: {
+			followerId: follower.id,
+			followeeId: followee.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 2eebe8a90..cbc6097f4 100644
--- a/packages/backend/src/server/api/endpoints/following/delete.ts
+++ b/packages/backend/src/server/api/endpoints/following/delete.ts
@@ -69,12 +69,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not following
-	const exist = await Followings.findOneBy({
-		followerId: follower.id,
-		followeeId: followee.id,
+	const exist = await Followings.exist({
+		where: {
+			followerId: follower.id,
+			followeeId: followee.id,
+		},
 	});
 
-	if (exist == null) {
+	if (!exist) {
 		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 fd46406bd..2506e40aa 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
@@ -40,12 +40,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	}
 
 	// if already liked
-	const exist = await GalleryLikes.findOneBy({
-		postId: post.id,
-		userId: user.id,
+	const exist = await GalleryLikes.exist({
+		where: {
+			postId: post.id,
+			userId: user.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 5218dba87..e44445b1b 100644
--- a/packages/backend/src/server/api/endpoints/i/read-announcement.ts
+++ b/packages/backend/src/server/api/endpoints/i/read-announcement.ts
@@ -30,9 +30,11 @@ export const paramDef = {
 
 export default define(meta, paramDef, async (ps, user) => {
 	// Check if announcement exists
-	const announcement = await Announcements.findOneBy({ id: ps.announcementId });
+	const exist = await Announcements.findOneBy({
+		where: { id: ps.announcementId },
+	});
 
-	if (announcement == null) {
+	if (!exist) {
 		throw new ApiError(meta.errors.noSuchAnnouncement);
 	}
 
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 308442bf7..3a410fa0e 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 token = await AccessTokens.findOneBy({ id: ps.tokenId });
+	const exist = await AccessTokens.exist({ where: { id: ps.tokenId } });
 
-	if (token) {
+	if (exist) {
 		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 bacab9b45..7b2f10905 100644
--- a/packages/backend/src/server/api/endpoints/mute/create.ts
+++ b/packages/backend/src/server/api/endpoints/mute/create.ts
@@ -64,12 +64,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already muting
-	const exist = await Mutings.findOneBy({
-		muterId: muter.id,
-		muteeId: mutee.id,
+	const exist = await Mutings.exist({
+		where: {
+			muterId: muter.id,
+			muteeId: mutee.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 41b8ab979..e15221046 100644
--- a/packages/backend/src/server/api/endpoints/notes/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/create.ts
@@ -224,11 +224,13 @@ export default define(meta, paramDef, async (ps, user) => {
 
 		// Check blocking
 		if (renote.userId !== user.id) {
-			const block = await Blockings.findOneBy({
-				blockerId: renote.userId,
-				blockeeId: user.id,
+			const isBlocked = await Blockings.exist({
+				where: {
+					blockerId: renote.userId,
+					blockeeId: user.id,
+				},
 			});
-			if (block) {
+			if (isBlocked) {
 				throw new ApiError(meta.errors.youHaveBeenBlocked);
 			}
 		}
@@ -249,11 +251,13 @@ export default define(meta, paramDef, async (ps, user) => {
 
 		// Check blocking
 		if (reply.userId !== user.id) {
-			const block = await Blockings.findOneBy({
-				blockerId: reply.userId,
-				blockeeId: user.id,
+			const isBlocked = await Blockings.exist({
+				where: {
+					blockerId: reply.userId,
+					blockeeId: user.id,
+				},
 			});
-			if (block) {
+			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 835594f03..64862a373 100644
--- a/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
@@ -43,12 +43,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// if already favorited
-	const exist = await NoteFavorites.findOneBy({
-		noteId: note.id,
-		userId: user.id,
+	const exist = await NoteFavorites.exist({
+		where: {
+			noteId: note.id,
+			userId: user.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 f14ed39eb..03482c961 100644
--- a/packages/backend/src/server/api/endpoints/pages/like.ts
+++ b/packages/backend/src/server/api/endpoints/pages/like.ts
@@ -40,12 +40,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	}
 
 	// if already liked
-	const exist = await PageLikes.findOneBy({
-		pageId: page.id,
-		userId: user.id,
+	const exist = await PageLikes.exist({
+		where: {
+			pageId: page.id,
+			userId: user.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		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 09c8cb6fa..5310382a4 100644
--- a/packages/backend/src/server/api/endpoints/promo/read.ts
+++ b/packages/backend/src/server/api/endpoints/promo/read.ts
@@ -33,12 +33,14 @@ export default define(meta, paramDef, async (ps, user) => {
 		throw err;
 	});
 
-	const exist = await PromoReads.findOneBy({
-		noteId: note.id,
-		userId: user.id,
+	const exist = await PromoReads.exist({
+		where: {
+			noteId: note.id,
+			userId: user.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		return;
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/users/followers.ts b/packages/backend/src/server/api/endpoints/users/followers.ts
index 855ab3573..31719bad3 100644
--- a/packages/backend/src/server/api/endpoints/users/followers.ts
+++ b/packages/backend/src/server/api/endpoints/users/followers.ts
@@ -98,11 +98,13 @@ export default define(meta, paramDef, async (ps, me) => {
 		if (me == null) {
 			throw new ApiError(meta.errors.forbidden);
 		} else if (me.id !== user.id) {
-			const following = await Followings.findOneBy({
-				followeeId: user.id,
-				followerId: me.id,
+			const isFollowed = await Followings.exist({
+				where: {
+					followeeId: user.id,
+					followerId: me.id,
+				},
 			});
-			if (following == null) {
+			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 37d69b048..1c1da0e11 100644
--- a/packages/backend/src/server/api/endpoints/users/following.ts
+++ b/packages/backend/src/server/api/endpoints/users/following.ts
@@ -97,11 +97,13 @@ export default define(meta, paramDef, async (ps, me) => {
 		if (me == null) {
 			throw new ApiError(meta.errors.forbidden);
 		} else if (me.id !== user.id) {
-			const following = await Followings.findOneBy({
-				followeeId: user.id,
-				followerId: me.id,
+			const isFollowing = await Followings.exist({
+				where: {
+					followeeId: user.id,
+					followerId: me.id,
+				},
 			});
-			if (following == null) {
+			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 a14195bbc..10b9acc42 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/push.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/push.ts
@@ -52,12 +52,14 @@ export const paramDef = {
 
 export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the list
-	const userList = await UserLists.findOneBy({
-		id: ps.listId,
-		userId: me.id,
+	const userList = await UserLists.exist({
+		where: {
+			id: ps.listId,
+			userId: me.id,
+		},
 	});
 
-	if (userList == null) {
+	if (!exist) {
 		throw new ApiError(meta.errors.noSuchList);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/users/lists/show.ts b/packages/backend/src/server/api/endpoints/users/lists/show.ts
index 716fd405d..8479a4e03 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/show.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/show.ts
@@ -37,12 +37,14 @@ export const paramDef = {
 
 export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the list
-	const userList = await UserLists.findOneBy({
-		id: ps.listId,
-		userId: me.id,
+	const exist = await UserLists.exist({
+		where: {
+			id: ps.listId,
+			userId: me.id,
+		},
 	});
 
-	if (userList == null) {
+	if (!exist) {
 		throw new ApiError(meta.errors.noSuchList);
 	}
 
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 0b52f6912..d14031950 100644
--- a/packages/backend/src/server/api/stream/channels/user-list.ts
+++ b/packages/backend/src/server/api/stream/channels/user-list.ts
@@ -22,11 +22,13 @@ export default class extends Channel {
 		this.listId = params.listId as string;
 
 		// Check existence and owner
-		const list = await UserLists.findOneBy({
-			id: this.listId,
-			userId: this.user!.id,
+		const exist = await UserLists.exist({
+			where: {
+				id: this.listId,
+				userId: this.user!.id,
+			},
 		});
-		if (!list) return;
+		if (!exist) return;
 
 		// Subscribe stream
 		this.subscriber.on(`userListStream:${this.listId}`, this.send);