diff --git a/packages/backend/src/core/NoteDraftService.ts b/packages/backend/src/core/NoteDraftService.ts
index 2b7da2b70d..159f0f6771 100644
--- a/packages/backend/src/core/NoteDraftService.ts
+++ b/packages/backend/src/core/NoteDraftService.ts
@@ -4,39 +4,58 @@
  */
 
 import { Inject, Injectable } from '@nestjs/common';
+import { In } from 'typeorm';
 import type { noteVisibilities, noteReactionAcceptances } from '@/types.js';
 import { DI } from '@/di-symbols.js';
-import type { MiNoteDraft, NoteDraftsRepository, MiNote, MiDriveFile, MiChannel } from '@/models/_.js';
+import type { MiNoteDraft, NoteDraftsRepository, MiNote, MiDriveFile, MiChannel, UsersRepository, DriveFilesRepository, NotesRepository, BlockingsRepository, ChannelsRepository } from '@/models/_.js';
 import { bindThis } from '@/decorators.js';
 import { RoleService } from '@/core/RoleService.js';
 import { IdService } from '@/core/IdService.js';
 import type { MiLocalUser, MiUser } from '@/models/User.js';
 import { IPoll } from '@/models/Poll.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
+import { isRenote, isQuote } from '@/misc/is-renote.js';
+import { NoteEntityService } from '@/core/entities/NoteEntityService.js';
 
 export type NoteDraftOptions = {
-	reply?: MiNote | null;
-	renote?: MiNote | null;
+	replyId?: MiNote['id'] | null;
+	renoteId?: MiNote['id'] | null;
 	text?: string | null;
 	cw?: string | null;
 	localOnly?: boolean | null;
 	reactionAcceptance?: typeof noteReactionAcceptances[number];
 	visibility?: typeof noteVisibilities[number];
-	files?: MiDriveFile[];
-	visibleUsers?: MiUser[];
+	fileIds?: MiDriveFile['id'][];
+	visibleUserIds?: MiUser['id'][];
 	hashtag?: string;
-	channel?: MiChannel | null;
+	channelId?: MiChannel['id'] | null;
 	poll?: (IPoll & { expiredAfter?: number | null }) | null;
 };
 
 @Injectable()
 export class NoteDraftService {
 	constructor(
+		@Inject(DI.blockingsRepository)
+		private blockingsRepository: BlockingsRepository,
+
 		@Inject(DI.noteDraftsRepository)
 		private noteDraftsRepository: NoteDraftsRepository,
 
+		@Inject(DI.notesRepository)
+		private notesRepository: NotesRepository,
+
+		@Inject(DI.usersRepository)
+		private usersRepository: UsersRepository,
+
+		@Inject(DI.driveFilesRepository)
+		private driveFilesRepository: DriveFilesRepository,
+
+		@Inject(DI.channelsRepository)
+		private channelsRepository: ChannelsRepository,
+
 		private roleService: RoleService,
 		private idService: IdService,
+		private noteEntityService: NoteEntityService,
 	) {
 	}
 
@@ -52,82 +71,59 @@ export class NoteDraftService {
 
 	@bindThis
 	public async create(me: MiLocalUser, data: NoteDraftOptions): Promise<MiNoteDraft> {
-		if (data.visibility == null) data.visibility = 'public';
-		if (data.localOnly == null) data.localOnly = false;
-		if (data.reactionAcceptance === undefined) data.reactionAcceptance = null;
-		if (data.channel != null) {
-			data.visibility = 'public';
-			data.visibleUsers = [];
-			data.localOnly = true;
-		}
+		//#region check draft limit
 
 		const currentCount = await this.noteDraftsRepository.countBy({
 			userId: me.id,
 		});
 		if (currentCount >= (await this.roleService.getUserPolicies(me.id)).noteDraftLimit) {
-			throw new IdentifiableError('c9a2c1d8-d153-40be-9cac-9fc2eb56b581', 'Too many drafts');
+			throw new IdentifiableError('9ee33bbe-fde3-4c71-9b51-e50492c6b9c8', 'Too many drafts');
+		}
+		//#endregion
+
+		if (data.poll) {
+			if (typeof data.poll.expiresAt === 'number') {
+				if (data.poll.expiresAt < Date.now()) {
+					throw new IdentifiableError('04da457d-b083-4055-9082-955525eda5a5', 'Cannot create expired poll');
+				}
+			} else if (typeof data.poll.expiredAfter === 'number') {
+				data.poll.expiresAt = new Date(Date.now() + data.poll.expiredAfter);
+			}
 		}
 
-		const draft = await this.noteDraftsRepository.insertOne({
-			id: this.idService.gen(),
-			visibility: data.visibility,
-			cw: data.cw,
-			fileIds: data.files ? data.files.map(file => file.id) : [],
-			replyId: data.reply ? data.reply.id : null,
-			renoteId: data.renote ? data.renote.id : null,
-			channelId: data.channel ? data.channel.id : null,
-			text: data.text ?? null,
-			hashtag: data.hashtag,
-			hasPoll: data.poll != null,
-			pollChoices: data.poll ? data.poll.choices : [],
-			pollMultiple: data.poll ? data.poll.multiple : false,
-			pollExpiresAt: data.poll ? data.poll.expiresAt : null,
-			pollExpiredAfter: data.poll ? data.poll.expiredAfter : null,
-			localOnly: data.localOnly,
-			visibleUserIds: data.visibleUsers ? data.visibleUsers.map(user => user.id) : [],
-			userId: me.id,
-		});
+		const appliedDraft = await this.checkAndSetDraftNoteOptions(me, this.noteDraftsRepository.create(), data);
+
+		appliedDraft.id = this.idService.gen();
+		appliedDraft.userId = me.id;
+		const draft = this.noteDraftsRepository.save(appliedDraft);
 
 		return draft;
 	}
 
 	@bindThis
-	public async update(me: MiLocalUser, draftId: MiNoteDraft['id'], data: NoteDraftOptions): Promise<void> {
-		if (data.visibility == null) data.visibility = 'public';
-		if (data.localOnly == null) data.localOnly = false;
-		if (data.reactionAcceptance === undefined) data.reactionAcceptance = null;
-		if (data.channel != null) {
-			data.visibility = 'public';
-			data.visibleUsers = [];
-			data.localOnly = true;
-		}
-
+	public async update(me: MiLocalUser, draftId: MiNoteDraft['id'], data: NoteDraftOptions): Promise<MiNoteDraft> {
 		const draft = await this.noteDraftsRepository.findOneBy({
 			id: draftId,
 			userId: me.id,
 		});
 
 		if (draft == null) {
-			throw new IdentifiableError('03a9514d-ff73-4c48-a55a-0282c8311ec6', 'No such note draft');
+			throw new IdentifiableError('49cd6b9d-848e-41ee-b0b9-adaca711a6b1', 'No such note draft');
 		}
 
-		await this.noteDraftsRepository.update(draft.id, {
-			visibility: data.visibility,
-			cw: data.cw,
-			fileIds: data.files ? data.files.map(file => file.id) : [],
-			replyId: data.reply ? data.reply.id : null,
-			renoteId: data.renote ? data.renote.id : null,
-			channelId: data.channel ? data.channel.id : null,
-			text: data.text ?? null,
-			hashtag: data.hashtag,
-			hasPoll: data.poll != null,
-			pollChoices: data.poll ? data.poll.choices : [],
-			pollMultiple: data.poll ? data.poll.multiple : false,
-			pollExpiresAt: data.poll ? data.poll.expiresAt : null,
-			pollExpiredAfter: data.poll ? data.poll.expiredAfter : null,
-			visibleUserIds: data.visibleUsers ? data.visibleUsers.map(user => user.id) : [],
-			localOnly: data.localOnly,
-		});
+		if (data.poll) {
+			if (typeof data.poll.expiresAt === 'number') {
+				if (data.poll.expiresAt < Date.now()) {
+					throw new IdentifiableError('04da457d-b083-4055-9082-955525eda5a5', 'Cannot create expired poll');
+				}
+			} else if (typeof data.poll.expiredAfter === 'number') {
+				data.poll.expiresAt = new Date(Date.now() + data.poll.expiredAfter);
+			}
+		}
+
+		const appliedDraft = await this.checkAndSetDraftNoteOptions(me, draft, data);
+
+		return await this.noteDraftsRepository.save(appliedDraft);
 	}
 
 	@bindThis
@@ -138,9 +134,183 @@ export class NoteDraftService {
 		});
 
 		if (draft == null) {
-			throw new IdentifiableError('03a9514d-ff73-4c48-a55a-0282c8311ec6', 'No such note draft');
+			throw new IdentifiableError('49cd6b9d-848e-41ee-b0b9-adaca711a6b1', 'No such note draft');
 		}
 
 		await this.noteDraftsRepository.delete(draft.id);
 	}
+
+	@bindThis
+	public async getDraft(me: MiLocalUser, draftId: MiNoteDraft['id']): Promise<MiNoteDraft> {
+		// Errorは仮置きで置換が簡単になるようにしておく
+
+		const draft = await this.noteDraftsRepository.findOneBy({
+			id: draftId,
+			userId: me.id,
+		});
+
+		if (draft == null) {
+			throw new IdentifiableError('49cd6b9d-848e-41ee-b0b9-adaca711a6b1', 'No such note draft');
+		}
+
+		return draft;
+	}
+
+	// 関連エンティティを取得し紐づける部分を共通化する
+	@bindThis
+	public async checkAndSetDraftNoteOptions(
+		me: MiLocalUser,
+		draft: MiNoteDraft,
+		data: NoteDraftOptions,
+	): Promise<MiNoteDraft> {
+		data.visibility ??= 'public';
+		data.localOnly ??= false;
+		if (data.reactionAcceptance === undefined) data.reactionAcceptance = null;
+		if (data.channelId != null) {
+			data.visibility = 'public';
+			data.visibleUserIds = [];
+			data.localOnly = true;
+		}
+
+		let appliedDraft = draft;
+
+		//#region visibleUsers
+		let visibleUsers: MiUser[] = [];
+		if (data.visibleUserIds != null) {
+			visibleUsers = await this.usersRepository.findBy({
+				id: In(data.visibleUserIds),
+			});
+		}
+		//#endregion
+
+		//#region files
+		let files: MiDriveFile[] = [];
+		const fileIds = data.fileIds ?? null;
+		if (fileIds != null) {
+			files = await this.driveFilesRepository.createQueryBuilder('file')
+				.where('file.userId = :userId AND file.id IN (:...fileIds)', {
+					userId: me.id,
+					fileIds: fileIds,
+				})
+				.orderBy('array_position(ARRAY[:...fileIds], "id"::text)')
+				.setParameters({ fileIds })
+				.getMany();
+
+			if (files.length !== fileIds.length) {
+				throw new IdentifiableError('b6992544-63e7-67f0-fa7f-32444b1b5306', 'No such drive file');
+			}
+		}
+		//#endregion
+
+		//#region renote
+		let renote: MiNote | null = null;
+		if (data.renoteId != null) {
+			renote = await this.notesRepository.findOneBy({ id: data.renoteId });
+
+			if (renote == null) {
+				throw new IdentifiableError('64929870-2540-4d11-af41-3b484d78c956', 'No such renote');
+			} else if (isRenote(renote) && !isQuote(renote)) {
+				throw new IdentifiableError('76cc5583-5a14-4ad3-8717-0298507e32db', 'Cannot renote');
+			}
+
+			// Check blocking
+			if (renote.userId !== me.id) {
+				const blockExist = await this.blockingsRepository.exists({
+					where: {
+						blockerId: renote.userId,
+						blockeeId: me.id,
+					},
+				});
+				if (blockExist) {
+					throw new IdentifiableError('075ca298-e6e7-485a-b570-51a128bb5168', 'You have been blocked by the user');
+				}
+			}
+
+			if (renote.visibility === 'followers' && renote.userId !== me.id) {
+				// 他人のfollowers noteはreject
+				throw new IdentifiableError('81eb8188-aea1-4e35-9a8f-3334a3be9855', 'Cannot Renote Due to Visibility');
+			} else if (renote.visibility === 'specified') {
+				// specified / direct noteはreject
+				throw new IdentifiableError('81eb8188-aea1-4e35-9a8f-3334a3be9855', 'Cannot Renote Due to Visibility');
+			}
+
+			if (renote.channelId && renote.channelId !== data.channelId) {
+				// チャンネルのノートに対しリノート要求がきたとき、チャンネル外へのリノート可否をチェック
+				// リノートのユースケースのうち、チャンネル内→チャンネル外は少数だと考えられるため、JOINはせず必要な時に都度取得する
+				const renoteChannel = await this.channelsRepository.findOneBy({ id: renote.channelId });
+				if (renoteChannel == null) {
+					// リノートしたいノートが書き込まれているチャンネルがない
+					throw new IdentifiableError('6815399a-6f13-4069-b60d-ed5156249d12', 'No such channel');
+				} else if (!renoteChannel.allowRenoteToExternal) {
+					// リノート作成のリクエストだが、対象チャンネルがリノート禁止だった場合
+					throw new IdentifiableError('ed1952ac-2d26-4957-8b30-2deda76bedf7', 'Cannot Renote to External');
+				}
+			}
+		}
+		//#endregion
+
+		//#region reply
+		let reply: MiNote | null = null;
+		if (data.replyId != null) {
+			// Fetch reply
+			reply = await this.notesRepository.findOneBy({ id: data.replyId });
+
+			if (reply == null) {
+				throw new IdentifiableError('c4721841-22fc-4bb7-ad3d-897ef1d375b5', 'No such reply');
+			} else if (isRenote(reply) && !isQuote(reply)) {
+				throw new IdentifiableError('e6c10b57-2c09-4da3-bd4d-eda05d51d140', 'Cannot reply To Pure Renote');
+			} else if (!await this.noteEntityService.isVisibleForMe(reply, me.id)) {
+				throw new IdentifiableError('593c323c-6b6a-4501-a25c-2f36bd2a93d6', 'Cannot reply To Invisible Note');
+			} else if (reply.visibility === 'specified' && data.visibility !== 'specified') {
+				throw new IdentifiableError('215dbc76-336c-4d2a-9605-95766ba7dab0', 'Cannot reply To Specified Note With Extended Visibility');
+			}
+
+			// Check blocking
+			if (reply.userId !== me.id) {
+				const blockExist = await this.blockingsRepository.exists({
+					where: {
+						blockerId: reply.userId,
+						blockeeId: me.id,
+					},
+				});
+				if (blockExist) {
+					throw new IdentifiableError('075ca298-e6e7-485a-b570-51a128bb5168', 'You have been blocked by the user');
+				}
+			}
+		}
+		//#endregion
+
+		//#region channel
+		let channel: MiChannel | null = null;
+		if (data.channelId != null) {
+			channel = await this.channelsRepository.findOneBy({ id: data.channelId, isArchived: false });
+
+			if (channel == null) {
+				throw new IdentifiableError('6815399a-6f13-4069-b60d-ed5156249d12', 'No such channel');
+			}
+		}
+		//#endregion
+
+		appliedDraft = {
+			...appliedDraft,
+			visibility: data.visibility,
+			cw: data.cw ?? null,
+			fileIds: fileIds ?? [],
+			replyId: data.replyId ?? null,
+			renoteId: data.renoteId ?? null,
+			channelId: data.channelId ?? null,
+			text: data.text ?? null,
+			hashtag: data.hashtag ?? null,
+			hasPoll: data.poll != null,
+			pollChoices: data.poll ? data.poll.choices : [],
+			pollMultiple: data.poll ? data.poll.multiple : false,
+			pollExpiresAt: data.poll ? data.poll.expiresAt : null,
+			pollExpiredAfter: data.poll ? data.poll.expiredAfter ?? null : null,
+			visibleUserIds: data.visibleUserIds ?? [],
+			localOnly: data.localOnly,
+			reactionAcceptance: data.reactionAcceptance,
+		} satisfies MiNoteDraft;
+
+		return appliedDraft;
+	}
 }
diff --git a/packages/backend/src/models/NoteDraft.ts b/packages/backend/src/models/NoteDraft.ts
index a62c79cb82..edae254bb8 100644
--- a/packages/backend/src/models/NoteDraft.ts
+++ b/packages/backend/src/models/NoteDraft.ts
@@ -104,7 +104,7 @@ export class MiNoteDraft {
 	@Column('varchar', {
 		length: 128, nullable: true,
 	})
-	public hashtag: string;
+	public hashtag: string | null;
 
 	@Index()
 	@Column({
diff --git a/packages/backend/src/server/api/endpoints/notes/drafts/create.ts b/packages/backend/src/server/api/endpoints/notes/drafts/create.ts
index 1029f21ee7..1c28ec22d0 100644
--- a/packages/backend/src/server/api/endpoints/notes/drafts/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/drafts/create.ts
@@ -3,18 +3,12 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { Inject, Injectable } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import ms from 'ms';
-import { In } from 'typeorm';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import { NoteDraftService } from '@/core/NoteDraftService.js';
 import { MAX_NOTE_TEXT_LENGTH } from '@/const.js';
-import type { MiNote, MiChannel, MiDriveFile, UsersRepository, NotesRepository, BlockingsRepository, DriveFilesRepository, ChannelsRepository } from '@/models/_.js';
-import { DI } from '@/di-symbols.js';
-import { MiUser } from '@/models/_.js';
 import { ApiError } from '@/server/api/error.js';
-import { isQuote, isRenote } from '@/misc/is-renote.js';
-import { NoteEntityService } from '@/core/entities/NoteEntityService.js';
 import { NoteDraftEntityService } from '@/core/entities/NoteDraftEntityService.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
 
@@ -129,6 +123,12 @@ export const meta = {
 			code: 'TOO_MANY_DRAFTS',
 			id: '9ee33bbe-fde3-4c71-9b51-e50492c6b9c8',
 		},
+
+		cannotRenoteToExternal: {
+			message: 'Cannot Renote to External.',
+			code: 'CANNOT_RENOTE_TO_EXTERNAL',
+			id: 'ed1952ac-2d26-4957-8b30-2deda76bedf7',
+		},
 	},
 
 	limit: {
@@ -190,147 +190,12 @@ export const paramDef = {
 @Injectable()
 export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
 	constructor(
-		@Inject(DI.usersRepository)
-		private usersRepository: UsersRepository,
-
-		@Inject(DI.notesRepository)
-		private notesRepository: NotesRepository,
-
-		@Inject(DI.blockingsRepository)
-		private blockingsRepository: BlockingsRepository,
-
-		@Inject(DI.driveFilesRepository)
-		private driveFilesRepository: DriveFilesRepository,
-
-		@Inject(DI.channelsRepository)
-		private channelsRepository: ChannelsRepository,
-
-		private noteEntityService: NoteEntityService,
 		private noteDraftService: NoteDraftService,
 		private noteDraftEntityService: NoteDraftEntityService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			// TODO: ノートendpointのバリデーションとServiceとして共通化
-			let visibleUsers: MiUser[] = [];
-			if (ps.visibleUserIds) {
-				visibleUsers = await this.usersRepository.findBy({
-					id: In(ps.visibleUserIds),
-				});
-			}
-
-			let files: MiDriveFile[] = [];
-			const fileIds = ps.fileIds ?? null;
-			if (fileIds != null) {
-				files = await this.driveFilesRepository.createQueryBuilder('file')
-					.where('file.userId = :userId AND file.id IN (:...fileIds)', {
-						userId: me.id,
-						fileIds,
-					})
-					.orderBy('array_position(ARRAY[:...fileIds], "id"::text)')
-					.setParameters({ fileIds })
-					.getMany();
-
-				if (files.length !== fileIds.length) {
-					throw new ApiError(meta.errors.noSuchFile);
-				}
-			}
-
-			let renote: MiNote | null = null;
-			if (ps.renoteId != null) {
-				// Fetch renote to note
-				renote = await this.notesRepository.findOneBy({ id: ps.renoteId });
-
-				if (renote == null) {
-					throw new ApiError(meta.errors.noSuchRenoteTarget);
-				} else if (isRenote(renote) && !isQuote(renote)) {
-					throw new ApiError(meta.errors.cannotReRenote);
-				}
-
-				// Check blocking
-				if (renote.userId !== me.id) {
-					const blockExist = await this.blockingsRepository.exists({
-						where: {
-							blockerId: renote.userId,
-							blockeeId: me.id,
-						},
-					});
-					if (blockExist) {
-						throw new ApiError(meta.errors.youHaveBeenBlocked);
-					}
-				}
-
-				if (renote.visibility === 'followers' && renote.userId !== me.id) {
-					// 他人のfollowers noteはreject
-					throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
-				} else if (renote.visibility === 'specified') {
-					// specified / direct noteはreject
-					throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
-				}
-
-				if (renote.channelId && renote.channelId !== ps.channelId) {
-					// チャンネルのノートに対しリノート要求がきたとき、チャンネル外へのリノート可否をチェック
-					// リノートのユースケースのうち、チャンネル内→チャンネル外は少数だと考えられるため、JOINはせず必要な時に都度取得する
-					const renoteChannel = await this.channelsRepository.findOneBy({ id: renote.channelId });
-					if (renoteChannel == null) {
-						// リノートしたいノートが書き込まれているチャンネルが無い
-						throw new ApiError(meta.errors.noSuchChannel);
-					} else if (!renoteChannel.allowRenoteToExternal) {
-						// リノート作成のリクエストだが、対象チャンネルがリノート禁止だった場合
-						throw new ApiError(meta.errors.cannotRenoteOutsideOfChannel);
-					}
-				}
-			}
-
-			let reply: MiNote | null = null;
-			if (ps.replyId != null) {
-				// Fetch reply
-				reply = await this.notesRepository.findOneBy({ id: ps.replyId });
-
-				if (reply == null) {
-					throw new ApiError(meta.errors.noSuchReplyTarget);
-				} else if (isRenote(reply) && !isQuote(reply)) {
-					throw new ApiError(meta.errors.cannotReplyToPureRenote);
-				} else if (!await this.noteEntityService.isVisibleForMe(reply, me.id)) {
-					throw new ApiError(meta.errors.cannotReplyToInvisibleNote);
-				} else if (reply.visibility === 'specified' && ps.visibility !== 'specified') {
-					throw new ApiError(meta.errors.cannotReplyToSpecifiedVisibilityNoteWithExtendedVisibility);
-				}
-
-				// Check blocking
-				if (reply.userId !== me.id) {
-					const blockExist = await this.blockingsRepository.exists({
-						where: {
-							blockerId: reply.userId,
-							blockeeId: me.id,
-						},
-					});
-					if (blockExist) {
-						throw new ApiError(meta.errors.youHaveBeenBlocked);
-					}
-				}
-			}
-
-			if (ps.poll) {
-				if (typeof ps.poll.expiresAt === 'number') {
-					if (ps.poll.expiresAt < Date.now()) {
-						throw new ApiError(meta.errors.cannotCreateAlreadyExpiredPoll);
-					}
-				} else if (typeof ps.poll.expiredAfter === 'number') {
-					ps.poll.expiresAt = Date.now() + ps.poll.expiredAfter;
-				}
-			}
-
-			let channel: MiChannel | null = null;
-			if (ps.channelId != null) {
-				channel = await this.channelsRepository.findOneBy({ id: ps.channelId, isArchived: false });
-
-				if (channel == null) {
-					throw new ApiError(meta.errors.noSuchChannel);
-				}
-			}
-
 			const draft = await this.noteDraftService.create(me, {
-				files: files,
+				fileIds: ps.fileIds,
 				poll: ps.poll ? {
 					choices: ps.poll.choices,
 					multiple: ps.poll.multiple ?? false,
@@ -338,18 +203,47 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 					expiredAfter: ps.poll.expiredAfter ?? null,
 				} : undefined,
 				text: ps.text ?? null,
-				reply,
-				renote,
+				replyId: ps.replyId ?? undefined,
+				renoteId: ps.renoteId ?? undefined,
 				cw: ps.cw ?? null,
 				...(ps.hashtag ? { hashtag: ps.hashtag } : {}),
 				localOnly: ps.localOnly,
 				reactionAcceptance: ps.reactionAcceptance,
 				visibility: ps.visibility,
-				visibleUsers,
-				channel,
+				visibleUserIds: ps.visibleUserIds ?? [],
+				channelId: ps.channelId ?? undefined,
 			}).catch((err) => {
-				if (err instanceof IdentifiableError && err.id === 'c9a2c1d8-d153-40be-9cac-9fc2eb56b581') {
-					throw new ApiError(meta.errors.tooManyDrafts);
+				if (err instanceof IdentifiableError) {
+					switch (err.id) {
+						case '9ee33bbe-fde3-4c71-9b51-e50492c6b9c8':
+							throw new ApiError(meta.errors.tooManyDrafts);
+						case '04da457d-b083-4055-9082-955525eda5a5':
+							throw new ApiError(meta.errors.cannotCreateAlreadyExpiredPoll);
+						case 'b6992544-63e7-67f0-fa7f-32444b1b5306':
+							throw new ApiError(meta.errors.noSuchFile);
+						case '64929870-2540-4d11-af41-3b484d78c956':
+							throw new ApiError(meta.errors.noSuchRenoteTarget);
+						case '76cc5583-5a14-4ad3-8717-0298507e32db':
+							throw new ApiError(meta.errors.cannotReRenote);
+						case '075ca298-e6e7-485a-b570-51a128bb5168':
+							throw new ApiError(meta.errors.youHaveBeenBlocked);
+						case '81eb8188-aea1-4e35-9a8f-3334a3be9855':
+							throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
+						case '6815399a-6f13-4069-b60d-ed5156249d12':
+							throw new ApiError(meta.errors.noSuchChannel);
+						case 'ed1952ac-2d26-4957-8b30-2deda76bedf7':
+							throw new ApiError(meta.errors.cannotRenoteToExternal);
+						case 'c4721841-22fc-4bb7-ad3d-897ef1d375b5':
+							throw new ApiError(meta.errors.noSuchReplyTarget);
+						case 'e6c10b57-2c09-4da3-bd4d-eda05d51d140':
+							throw new ApiError(meta.errors.cannotReplyToPureRenote);
+						case '593c323c-6b6a-4501-a25c-2f36bd2a93d6':
+							throw new ApiError(meta.errors.cannotReplyToInvisibleNote);
+						case '215dbc76-336c-4d2a-9605-95766ba7dab0':
+							throw new ApiError(meta.errors.cannotReplyToSpecifiedVisibilityNoteWithExtendedVisibility);
+						default:
+							throw err;
+					}
 				}
 				throw err;
 			});
diff --git a/packages/backend/src/server/api/endpoints/notes/drafts/update.ts b/packages/backend/src/server/api/endpoints/notes/drafts/update.ts
index fbe6b5f993..ee221fb765 100644
--- a/packages/backend/src/server/api/endpoints/notes/drafts/update.ts
+++ b/packages/backend/src/server/api/endpoints/notes/drafts/update.ts
@@ -5,17 +5,11 @@
 
 import { Injectable } from '@nestjs/common';
 import ms from 'ms';
-import { In } from 'typeorm';
-import { Inject } from '@nestjs/common';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import { NoteDraftService } from '@/core/NoteDraftService.js';
 import { MAX_NOTE_TEXT_LENGTH } from '@/const.js';
-import type { MiNote, MiChannel, MiDriveFile, UsersRepository, NotesRepository, BlockingsRepository, DriveFilesRepository, ChannelsRepository } from '@/models/_.js';
-import { isRenote, isQuote } from '@/misc/is-renote.js';
-import type { MiUser } from '@/models/User.js';
-import { DI } from '@/di-symbols.js';
-import { NoteEntityService } from '@/core/entities/NoteEntityService.js';
 import { NoteDraftEntityService } from '@/core/entities/NoteDraftEntityService.js';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
 import { ApiError } from '../../../error.js';
 
 export const meta = {
@@ -76,9 +70,9 @@ export const meta = {
 			id: '3ac74a84-8fd5-4bb0-870f-01804f82ce15',
 		},
 
-		cannotReplyToSpecifiedVisibilityNoteWithExtendedVisibility: {
+		cannotReplyToSpecifiedNoteWithExtendedVisibility: {
 			message: 'You cannot reply to a specified visibility note with extended visibility.',
-			code: 'CANNOT_REPLY_TO_SPECIFIED_VISIBILITY_NOTE_WITH_EXTENDED_VISIBILITY',
+			code: 'CANNOT_REPLY_TO_SPECIFIED_NOTE_WITH_EXTENDED_VISIBILITY',
 			id: 'ed940410-535c-4d5e-bfa3-af798671e93c',
 		},
 
@@ -135,6 +129,36 @@ export const meta = {
 			code: 'ACCESS_DENIED',
 			id: '56f35758-7dd5-468b-8439-5d6fb8ec9b8e',
 		},
+
+		noSuchRenote: {
+			message: 'No such renote.',
+			code: 'NO_SUCH_RENOTE',
+			id: '64929870-2540-4d11-af41-3b484d78c956',
+		},
+
+		cannotRenote: {
+			message: 'Cannot renote.',
+			code: 'CANNOT_RENOTE',
+			id: '76cc5583-5a14-4ad3-8717-0298507e32db',
+		},
+
+		cannotRenoteToExternal: {
+			message: 'Cannot Renote to External.',
+			code: 'CANNOT_RENOTE_TO_EXTERNAL',
+			id: 'ed1952ac-2d26-4957-8b30-2deda76bedf7',
+		},
+
+		noSuchReply: {
+			message: 'No such reply.',
+			code: 'NO_SUCH_REPLY',
+			id: 'c4721841-22fc-4bb7-ad3d-897ef1d375b5',
+		},
+
+		cannotReplyToSpecifiedVisibilityNoteWithExtendedVisibility: {
+			message: 'You cannot reply to a specified visibility note with extended visibility.',
+			code: 'CANNOT_REPLY_TO_SPECIFIED_VISIBILITY_NOTE_WITH_EXTENDED_VISIBILITY',
+			id: '215dbc76-336c-4d2a-9605-95766ba7dab0',
+		},
 	},
 
 	limit: {
@@ -198,157 +222,12 @@ export const paramDef = {
 @Injectable()
 export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
 	constructor(
-		@Inject(DI.usersRepository)
-		private usersRepository: UsersRepository,
-
-		@Inject(DI.notesRepository)
-		private notesRepository: NotesRepository,
-
-		@Inject(DI.blockingsRepository)
-		private blockingsRepository: BlockingsRepository,
-
-		@Inject(DI.driveFilesRepository)
-		private driveFilesRepository: DriveFilesRepository,
-
-		@Inject(DI.channelsRepository)
-		private channelsRepository: ChannelsRepository,
-
-		private noteEntityService: NoteEntityService,
 		private noteDraftService: NoteDraftService,
 		private noteDraftEntityService: NoteDraftEntityService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
-			const draft = await this.noteDraftService.get(me, ps.draftId);
-
-			if (draft == null) {
-				throw new ApiError(meta.errors.noSuchNoteDraft);
-			}
-
-			if (draft.userId !== me.id) {
-				throw new ApiError(meta.errors.accessDenied);
-			}
-
-			// TODO: ノートendpointのバリデーションとServiceとして共通化
-			let visibleUsers: MiUser[] = [];
-			if (ps.visibleUserIds) {
-				visibleUsers = await this.usersRepository.findBy({
-					id: In(ps.visibleUserIds),
-				});
-			}
-
-			let files: MiDriveFile[] = [];
-			const fileIds = ps.fileIds ?? null;
-			if (fileIds != null) {
-				files = await this.driveFilesRepository.createQueryBuilder('file')
-					.where('file.userId = :userId AND file.id IN (:...fileIds)', {
-						userId: me.id,
-						fileIds,
-					})
-					.orderBy('array_position(ARRAY[:...fileIds], "id"::text)')
-					.setParameters({ fileIds })
-					.getMany();
-
-				if (files.length !== fileIds.length) {
-					throw new ApiError(meta.errors.noSuchFile);
-				}
-			}
-
-			let renote: MiNote | null = null;
-			if (ps.renoteId != null) {
-				// Fetch renote to note
-				renote = await this.notesRepository.findOneBy({ id: ps.renoteId });
-
-				if (renote == null) {
-					throw new ApiError(meta.errors.noSuchRenoteTarget);
-				} else if (isRenote(renote) && !isQuote(renote)) {
-					throw new ApiError(meta.errors.cannotReRenote);
-				}
-
-				// Check blocking
-				if (renote.userId !== me.id) {
-					const blockExist = await this.blockingsRepository.exists({
-						where: {
-							blockerId: renote.userId,
-							blockeeId: me.id,
-						},
-					});
-					if (blockExist) {
-						throw new ApiError(meta.errors.youHaveBeenBlocked);
-					}
-				}
-
-				if (renote.visibility === 'followers' && renote.userId !== me.id) {
-					// 他人のfollowers noteはreject
-					throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
-				} else if (renote.visibility === 'specified') {
-					// specified / direct noteはreject
-					throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
-				}
-
-				if (renote.channelId && renote.channelId !== ps.channelId) {
-					// チャンネルのノートに対しリノート要求がきたとき、チャンネル外へのリノート可否をチェック
-					// リノートのユースケースのうち、チャンネル内→チャンネル外は少数だと考えられるため、JOINはせず必要な時に都度取得する
-					const renoteChannel = await this.channelsRepository.findOneBy({ id: renote.channelId });
-					if (renoteChannel == null) {
-						// リノートしたいノートが書き込まれているチャンネルが無い
-						throw new ApiError(meta.errors.noSuchChannel);
-					} else if (!renoteChannel.allowRenoteToExternal) {
-						// リノート作成のリクエストだが、対象チャンネルがリノート禁止だった場合
-						throw new ApiError(meta.errors.cannotRenoteOutsideOfChannel);
-					}
-				}
-			}
-
-			let reply: MiNote | null = null;
-			if (ps.replyId != null) {
-				// Fetch reply
-				reply = await this.notesRepository.findOneBy({ id: ps.replyId });
-
-				if (reply == null) {
-					throw new ApiError(meta.errors.noSuchReplyTarget);
-				} else if (isRenote(reply) && !isQuote(reply)) {
-					throw new ApiError(meta.errors.cannotReplyToPureRenote);
-				} else if (!await this.noteEntityService.isVisibleForMe(reply, me.id)) {
-					throw new ApiError(meta.errors.cannotReplyToInvisibleNote);
-				} else if (reply.visibility === 'specified' && ps.visibility !== 'specified') {
-					throw new ApiError(meta.errors.cannotReplyToSpecifiedVisibilityNoteWithExtendedVisibility);
-				}
-
-				// Check blocking
-				if (reply.userId !== me.id) {
-					const blockExist = await this.blockingsRepository.exists({
-						where: {
-							blockerId: reply.userId,
-							blockeeId: me.id,
-						},
-					});
-					if (blockExist) {
-						throw new ApiError(meta.errors.youHaveBeenBlocked);
-					}
-				}
-			}
-
-			if (ps.poll) {
-				if (typeof ps.poll.expiresAt === 'number') {
-					if (ps.poll.expiresAt < Date.now()) {
-						throw new ApiError(meta.errors.cannotCreateAlreadyExpiredPoll);
-					}
-				} else if (typeof ps.poll.expiredAfter === 'number') {
-					ps.poll.expiresAt = Date.now() + ps.poll.expiredAfter;
-				}
-			}
-
-			let channel: MiChannel | null = null;
-			if (ps.channelId != null) {
-				channel = await this.channelsRepository.findOneBy({ id: ps.channelId, isArchived: false });
-
-				if (channel == null) {
-					throw new ApiError(meta.errors.noSuchChannel);
-				}
-			}
-
-			await this.noteDraftService.update(me, draft.id, {
-				files: files,
+			const draft = await this.noteDraftService.update(me, ps.draftId, {
+				fileIds: ps.fileIds,
 				poll: ps.poll ? {
 					choices: ps.poll.choices,
 					multiple: ps.poll.multiple ?? false,
@@ -356,15 +235,61 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 					expiredAfter: ps.poll.expiredAfter ?? null,
 				} : undefined,
 				text: ps.text ?? null,
-				reply,
-				renote,
+				replyId: ps.replyId ?? undefined,
+				renoteId: ps.renoteId ?? undefined,
 				cw: ps.cw ?? null,
 				...(ps.hashtag ? { hashtag: ps.hashtag } : {}),
 				localOnly: ps.localOnly,
 				reactionAcceptance: ps.reactionAcceptance,
 				visibility: ps.visibility,
-				visibleUsers,
-				channel,
+				visibleUserIds: ps.visibleUserIds ?? [],
+				channelId: ps.channelId ?? undefined,
+			}).catch((err) => {
+				if (err instanceof IdentifiableError) {
+					switch (err.id) {
+						case '49cd6b9d-848e-41ee-b0b9-adaca711a6b1':
+							throw new ApiError(meta.errors.noSuchNoteDraft);
+						case '04da457d-b083-4055-9082-955525eda5a5':
+							throw new ApiError(meta.errors.cannotCreateAlreadyExpiredPoll);
+						case 'b6992544-63e7-67f0-fa7f-32444b1b5306':
+							throw new ApiError(meta.errors.noSuchFile);
+						case '64929870-2540-4d11-af41-3b484d78c956':
+							throw new ApiError(meta.errors.noSuchRenote);
+						case '76cc5583-5a14-4ad3-8717-0298507e32db':
+							throw new ApiError(meta.errors.cannotRenote);
+						case '075ca298-e6e7-485a-b570-51a128bb5168':
+							throw new ApiError(meta.errors.youHaveBeenBlocked);
+						case '81eb8188-aea1-4e35-9a8f-3334a3be9855':
+							throw new ApiError(meta.errors.cannotRenoteDueToVisibility);
+						case '6815399a-6f13-4069-b60d-ed5156249d12':
+							throw new ApiError(meta.errors.noSuchChannel);
+						case 'ed1952ac-2d26-4957-8b30-2deda76bedf7':
+							throw new ApiError(meta.errors.cannotRenoteToExternal);
+						case 'c4721841-22fc-4bb7-ad3d-897ef1d375b5':
+							throw new ApiError(meta.errors.noSuchReply);
+						case 'e6c10b57-2c09-4da3-bd4d-eda05d51d140':
+							throw new ApiError(meta.errors.cannotReplyToPureRenote);
+						case '593c323c-6b6a-4501-a25c-2f36bd2a93d6':
+							throw new ApiError(meta.errors.cannotReplyToInvisibleNote);
+						case '215dbc76-336c-4d2a-9605-95766ba7dab0':
+							throw new ApiError(meta.errors.cannotReplyToSpecifiedNoteWithExtendedVisibility);
+						case 'b5c90186-4ab0-49c8-9bba-a1f76c282ba4':
+							throw new ApiError(meta.errors.noSuchRenoteTarget);
+						case 'fd4cc33e-2a37-48dd-99cc-9b806eb2031a':
+							throw new ApiError(meta.errors.cannotReRenote);
+						case '749ee0f6-d3da-459a-bf02-282e2da4292c':
+							throw new ApiError(meta.errors.noSuchReplyTarget);
+						case '33510210-8452-094c-6227-4a6c05d99f00':
+							throw new ApiError(meta.errors.cannotRenoteOutsideOfChannel);
+						case 'aa6e01d3-a85c-669d-758a-76aab43af334':
+							throw new ApiError(meta.errors.containsProhibitedWords);
+						case '4de0363a-3046-481b-9b0f-feff3e211025':
+							throw new ApiError(meta.errors.containsTooManyMentions);
+						default:
+							throw err;
+					}
+				}
+				throw err;
 			});
 
 			const updatedDraft = await this.noteDraftEntityService.pack(draft, me);