diff --git a/packages/backend/src/server/api/mastodon/endpoints/account.ts b/packages/backend/src/server/api/mastodon/endpoints/account.ts
index 65caf71685..4fda37a482 100644
--- a/packages/backend/src/server/api/mastodon/endpoints/account.ts
+++ b/packages/backend/src/server/api/mastodon/endpoints/account.ts
@@ -33,7 +33,7 @@ export function apiAccountMastodon(router: Router): void {
             ctx.body = e.response.data;
         }
     });
-    router.patch('/v1/accounts/update_credentials', koaBody({ multipart: true }), async (ctx) => {
+    router.patch('/v1/accounts/update_credentials', async (ctx) => {
         const BASE_URL = `${ctx.protocol}://${ctx.hostname}`;
         const accessTokens = ctx.headers.authorization;
         const client = getClient(BASE_URL, accessTokens);
@@ -177,7 +177,7 @@ export function apiAccountMastodon(router: Router): void {
             ctx.body = e.response.data;
         }
     });
-    router.post<{ Params: { id: string } }>('/v1/accounts/:id/mute', koaBody({ multipart: true }), async (ctx) => {
+    router.post<{ Params: { id: string } }>('/v1/accounts/:id/mute', async (ctx) => {
         const BASE_URL = `${ctx.protocol}://${ctx.hostname}`;
         const accessTokens = ctx.headers.authorization;
         const client = getClient(BASE_URL, accessTokens);
diff --git a/packages/backend/src/server/api/mastodon/endpoints/filter.ts b/packages/backend/src/server/api/mastodon/endpoints/filter.ts
index b4f67cf1e6..f665f8d237 100644
--- a/packages/backend/src/server/api/mastodon/endpoints/filter.ts
+++ b/packages/backend/src/server/api/mastodon/endpoints/filter.ts
@@ -1,11 +1,10 @@
 import megalodon, { MegalodonInterface } from '@cutls/megalodon';
 import Router from "@koa/router";
-import { koaBody } from 'koa-body';
 import { getClient } from '../ApiMastodonCompatibleService.js';
 
 export function apiFilterMastodon(router: Router): void {
 
-	router.get('/v1/filters', koaBody({ multipart: true }), async (ctx) => {
+	router.get('/v1/filters', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
@@ -20,7 +19,7 @@ export function apiFilterMastodon(router: Router): void {
 		}
 	});
 
-	router.get('/v1/filters/:id', koaBody({ multipart: true }), async (ctx) => {
+	router.get('/v1/filters/:id', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
@@ -35,7 +34,7 @@ export function apiFilterMastodon(router: Router): void {
 		}
 	});
 
-	router.post('/v1/filters', koaBody({ multipart: true }), async (ctx) => {
+	router.post('/v1/filters', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
@@ -50,7 +49,7 @@ export function apiFilterMastodon(router: Router): void {
 		}
 	});
 
-	router.post('/v1/filters/:id', koaBody({ multipart: true }), async (ctx) => {
+	router.post('/v1/filters/:id', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
@@ -65,7 +64,7 @@ export function apiFilterMastodon(router: Router): void {
 		}
 	});
 
-	router.delete('/v1/filters/:id', koaBody({ multipart: true }), async (ctx) => {
+	router.delete('/v1/filters/:id', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
diff --git a/packages/backend/src/server/api/mastodon/endpoints/notifications.ts b/packages/backend/src/server/api/mastodon/endpoints/notifications.ts
index b4599de80f..e65b47f029 100644
--- a/packages/backend/src/server/api/mastodon/endpoints/notifications.ts
+++ b/packages/backend/src/server/api/mastodon/endpoints/notifications.ts
@@ -71,7 +71,7 @@ export function apiNotificationsMastodon(router: Router): void {
 		}
 	});
 
-	router.post('/v1/notification/:id/dismiss', koaBody({ multipart: true }), async (ctx) => {
+	router.post('/v1/notification/:id/dismiss', async (ctx) => {
 		const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 		const accessTokens = ctx.request.headers.authorization;
 		const client = getClient(BASE_URL, accessTokens);
diff --git a/packages/backend/src/server/api/mastodon/endpoints/status.ts b/packages/backend/src/server/api/mastodon/endpoints/status.ts
index cef966e47b..f01665537a 100644
--- a/packages/backend/src/server/api/mastodon/endpoints/status.ts
+++ b/packages/backend/src/server/api/mastodon/endpoints/status.ts
@@ -1,5 +1,4 @@
 import Router from "@koa/router";
-import { koaBody } from 'koa-body';
 import megalodon, { MegalodonInterface } from '@cutls/megalodon';
 import { getClient } from '../ApiMastodonCompatibleService.js';
 import fs from 'fs'
@@ -11,7 +10,7 @@ import axios from 'axios';
 const pump = promisify(pipeline);
 
 export function apiStatusMastodon(router: Router): void {
-    router.post('/v1/statuses', koaBody({ multipart: true }), async (ctx, reply) => {
+    router.post('/v1/statuses', async (ctx, reply) => {
         const BASE_URL = `${ctx.protocol}://${ctx.hostname}`;
         const accessTokens = ctx.headers.authorization;
         const client = getClient(BASE_URL, accessTokens);
@@ -284,7 +283,7 @@ export function apiStatusMastodon(router: Router): void {
             ctx.body = e.response.data;
         }
     });
-    router.put<{ Params: { id: string } }>('/v1/media/:id', koaBody({ multipart: true }), async (ctx, reply) => {
+    router.put<{ Params: { id: string } }>('/v1/media/:id',async (ctx, reply) => {
         const BASE_URL = `${ctx.protocol}://${ctx.hostname}`;
         const accessTokens = ctx.headers.authorization;
         const client = getClient(BASE_URL, accessTokens);
@@ -310,7 +309,7 @@ export function apiStatusMastodon(router: Router): void {
             ctx.body = e.response.data;
         }
     });
-    router.post<{ Params: { id: string } }>('/v1/polls/:id/votes', koaBody({ multipart: true }), async (ctx, reply) => {
+    router.post<{ Params: { id: string } }>('/v1/polls/:id/votes', async (ctx, reply) => {
         const BASE_URL = `${ctx.protocol}://${ctx.hostname}`;
         const accessTokens = ctx.headers.authorization;
         const client = getClient(BASE_URL, accessTokens);
diff --git a/packages/backend/src/server/api/mastodon/endpoints/timeline.ts b/packages/backend/src/server/api/mastodon/endpoints/timeline.ts
index 3fdb6ce881..2cbdf5a0e6 100644
--- a/packages/backend/src/server/api/mastodon/endpoints/timeline.ts
+++ b/packages/backend/src/server/api/mastodon/endpoints/timeline.ts
@@ -1,5 +1,4 @@
 import Router from "@koa/router";
-import { koaBody } from 'koa-body';
 import megalodon, { Entity, MegalodonInterface } from '@cutls/megalodon';
 import { getClient } from '../ApiMastodonCompatibleService.js'
 import { statusModel } from './status.js';
diff --git a/packages/backend/src/server/index.ts b/packages/backend/src/server/index.ts
index 14c127e8ba..6609627fea 100644
--- a/packages/backend/src/server/index.ts
+++ b/packages/backend/src/server/index.ts
@@ -20,7 +20,6 @@ import { createTemp } from "@/misc/create-temp.js";
 import { publishMainStream } from "@/services/stream.js";
 import * as Acct from "@/misc/acct.js";
 import { envOption } from "@/env.js";
-import {koaBody} from "koa-body";
 import megalodon, { MegalodonInterface } from '@cutls/megalodon';
 import activityPub from "./activitypub.js";
 import nodeinfo from "./nodeinfo.js";
@@ -141,16 +140,16 @@ router.get("/oauth/authorize", async (ctx) => {
 	ctx.redirect(Buffer.from(client_id?.toString() || '', 'base64').toString());
 });
 
-router.post("/oauth/token", koaBody({
-	json: false,
-	multipart: true
-}), async (ctx) => {
+router.post("/oauth/token", async (ctx) => {
 	const body: any = ctx.request.body;
 	const BASE_URL = `${ctx.request.protocol}://${ctx.request.hostname}`;
 	const generator = (megalodon as any).default;
 	const client = generator('misskey', BASE_URL, null) as MegalodonInterface;
 	const m = body.code.match(/^[a-zA-Z0-9-]+/);
-	if (!m.length) return { error: 'Invalid code' }
+	if (!m.length) {
+		ctx.body = {error: 'Invalid code'}
+		return
+	}
 	try {
 		const atData = await client.fetchAccessToken(null, body.client_secret, m[0]);
 		ctx.body = {