diff --git a/packages/backend/src/server/api/endpoints.ts b/packages/backend/src/server/api/endpoints.ts
index e7563555b..ff35d848d 100644
--- a/packages/backend/src/server/api/endpoints.ts
+++ b/packages/backend/src/server/api/endpoints.ts
@@ -270,14 +270,12 @@ import * as ep___serverInfo from './endpoints/server-info.js';
 import * as ep___stats from './endpoints/stats.js';
 import * as ep___sw_register from './endpoints/sw/register.js';
 import * as ep___sw_unregister from './endpoints/sw/unregister.js';
-import * as ep___test from './endpoints/test.js';
 import * as ep___username_available from './endpoints/username/available.js';
 import * as ep___users from './endpoints/users.js';
 import * as ep___users_clips from './endpoints/users/clips.js';
 import * as ep___users_followers from './endpoints/users/followers.js';
 import * as ep___users_following from './endpoints/users/following.js';
 import * as ep___users_gallery_posts from './endpoints/users/gallery/posts.js';
-import * as ep___users_getFrequentlyRepliedUsers from './endpoints/users/get-frequently-replied-users.js';
 import * as ep___users_groups_create from './endpoints/users/groups/create.js';
 import * as ep___users_groups_delete from './endpoints/users/groups/delete.js';
 import * as ep___users_groups_invitations_accept from './endpoints/users/groups/invitations/accept.js';
@@ -580,14 +578,12 @@ const eps = [
 	['stats', ep___stats],
 	['sw/register', ep___sw_register],
 	['sw/unregister', ep___sw_unregister],
-	['test', ep___test],
 	['username/available', ep___username_available],
 	['users', ep___users],
 	['users/clips', ep___users_clips],
 	['users/followers', ep___users_followers],
 	['users/following', ep___users_following],
 	['users/gallery/posts', ep___users_gallery_posts],
-	['users/get-frequently-replied-users', ep___users_getFrequentlyRepliedUsers],
 	['users/groups/create', ep___users_groups_create],
 	['users/groups/delete', ep___users_groups_delete],
 	['users/groups/invitations/accept', ep___users_groups_invitations_accept],
diff --git a/packages/backend/src/server/api/endpoints/test.ts b/packages/backend/src/server/api/endpoints/test.ts
deleted file mode 100644
index 9949237a7..000000000
--- a/packages/backend/src/server/api/endpoints/test.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-import define from '../define.js';
-
-export const meta = {
-	tags: ['non-productive'],
-
-	description: 'Endpoint for testing input validation.',
-
-	requireCredential: false,
-} as const;
-
-export const paramDef = {
-	type: 'object',
-	properties: {
-		required: { type: 'boolean' },
-		string: { type: 'string' },
-		default: { type: 'string', default: 'hello' },
-		nullableDefault: { type: 'string', nullable: true, default: 'hello' },
-		id: { type: 'string', format: 'misskey:id' },
-	},
-	required: ['required'],
-} as const;
-
-// eslint-disable-next-line import/no-default-export
-export default define(meta, paramDef, async (ps, me) => {
-	return ps;
-});
diff --git a/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts b/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts
deleted file mode 100644
index 56965d306..000000000
--- a/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts
+++ /dev/null
@@ -1,114 +0,0 @@
-import { Not, In, IsNull } from 'typeorm';
-import { maximum } from '@/prelude/array.js';
-import { Notes, Users } from '@/models/index.js';
-import define from '../../define.js';
-import { ApiError } from '../../error.js';
-import { getUser } from '../../common/getters.js';
-
-export const meta = {
-	tags: ['users'],
-
-	requireCredential: false,
-
-	description: 'Get a list of other users that the specified user frequently replies to.',
-
-	res: {
-		type: 'array',
-		optional: false, nullable: false,
-		items: {
-			type: 'object',
-			optional: false, nullable: false,
-			properties: {
-				user: {
-					type: 'object',
-					optional: false, nullable: false,
-					ref: 'UserDetailed',
-				},
-				weight: {
-					type: 'number',
-					optional: false, nullable: false,
-				},
-			},
-		},
-	},
-
-	errors: {
-		noSuchUser: {
-			message: 'No such user.',
-			code: 'NO_SUCH_USER',
-			id: 'e6965129-7b2a-40a4-bae2-cd84cd434822',
-		},
-	},
-} as const;
-
-export const paramDef = {
-	type: 'object',
-	properties: {
-		userId: { type: 'string', format: 'misskey:id' },
-		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
-	},
-	required: ['userId'],
-} as const;
-
-// eslint-disable-next-line import/no-default-export
-export default define(meta, paramDef, async (ps, me) => {
-	// Lookup user
-	const user = await getUser(ps.userId).catch(e => {
-		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
-		throw e;
-	});
-
-	// Fetch recent notes
-	const recentNotes = await Notes.find({
-		where: {
-			userId: user.id,
-			replyId: Not(IsNull()),
-		},
-		order: {
-			id: -1,
-		},
-		take: 1000,
-		select: ['replyId'],
-	});
-
-	// 投稿が少なかったら中断
-	if (recentNotes.length === 0) {
-		return [];
-	}
-
-	// TODO ミュートを考慮
-	const replyTargetNotes = await Notes.find({
-		where: {
-			id: In(recentNotes.map(p => p.replyId)),
-		},
-		select: ['userId'],
-	});
-
-	const repliedUsers: any = {};
-
-	// Extract replies from recent notes
-	for (const userId of replyTargetNotes.map(x => x.userId.toString())) {
-		if (repliedUsers[userId]) {
-			repliedUsers[userId]++;
-		} else {
-			repliedUsers[userId] = 1;
-		}
-	}
-
-	// Calc peak
-	const peak = maximum(Object.values(repliedUsers));
-
-	// Sort replies by frequency
-	const repliedUsersSorted = Object.keys(repliedUsers).sort((a, b) => repliedUsers[b] - repliedUsers[a]);
-
-	// Extract top replied users
-	const topRepliedUsers = repliedUsersSorted.slice(0, ps.limit);
-
-	// Make replies object (includes weights)
-	const repliesObj = await Promise.all(topRepliedUsers.map(async (user) => ({
-		user: await Users.pack(user, me, { detail: true }),
-		weight: repliedUsers[user] / peak,
-	})));
-
-	return repliesObj;
-});
diff --git a/packages/foundkey-js/etc/misskey-js.api.md b/packages/foundkey-js/etc/misskey-js.api.md
index 1a462ba4e..706f0216f 100644
--- a/packages/foundkey-js/etc/misskey-js.api.md
+++ b/packages/foundkey-js/etc/misskey-js.api.md
@@ -1977,10 +1977,6 @@ export type Endpoints = {
         req: TODO;
         res: TODO;
     };
-    'users/get-frequently-replied-users': {
-        req: TODO;
-        res: TODO;
-    };
     'users/groups/create': {
         req: TODO;
         res: TODO;
diff --git a/packages/foundkey-js/src/api.types.ts b/packages/foundkey-js/src/api.types.ts
index 9d26c993f..788c663fb 100644
--- a/packages/foundkey-js/src/api.types.ts
+++ b/packages/foundkey-js/src/api.types.ts
@@ -484,14 +484,12 @@ export type Endpoints = {
 	'stats': { req: NoParams; res: Stats; };
 	'sw/register': { req: TODO; res: TODO; };
 	'sw/unregister': { req: TODO; res: TODO; };
-	'test': { req: TODO; res: TODO; };
 	'username/available': { req: { username: string; }; res: { available: boolean; }; };
 	'users': { req: { limit?: number; offset?: number; sort?: UserSorting; origin?: OriginType; }; res: User[]; };
 	'users/clips': { req: TODO; res: TODO; };
 	'users/followers': { req: { userId?: User['id']; username?: User['username']; host?: User['host'] | null; limit?: number; sinceId?: Following['id']; untilId?: Following['id']; }; res: FollowingFollowerPopulated[]; };
 	'users/following': { req: { userId?: User['id']; username?: User['username']; host?: User['host'] | null; limit?: number; sinceId?: Following['id']; untilId?: Following['id']; }; res: FollowingFolloweePopulated[]; };
 	'users/gallery/posts': { req: TODO; res: TODO; };
-	'users/get-frequently-replied-users': { req: TODO; res: TODO; };
 	'users/groups/create': { req: TODO; res: TODO; };
 	'users/groups/delete': { req: { groupId: UserGroup['id'] }; res: null; };
 	'users/groups/invitations/accept': { req: TODO; res: TODO; };