diff --git a/src/server/api/api-handler.ts b/src/server/api/api-handler.ts
index 128c1a98d..0eef9ab5c 100644
--- a/src/server/api/api-handler.ts
+++ b/src/server/api/api-handler.ts
@@ -6,7 +6,7 @@ import call from './call';
 import { IUser } from '../../models/user';
 import { IApp } from '../../models/app';
 
-export default async (endpoint: IEndpoint, ctx: Koa.Context) => {
+export default async (endpoint: IEndpoint, ctx: Koa.BaseContext) => {
 	const body = ctx.is('multipart/form-data') ? (ctx.req as any).body : ctx.request.body;
 
 	const reply = (x?: any, y?: any) => {
diff --git a/src/server/api/common/signin.ts b/src/server/api/common/signin.ts
index 45a42e288..84cad3a93 100644
--- a/src/server/api/common/signin.ts
+++ b/src/server/api/common/signin.ts
@@ -3,7 +3,7 @@ import * as Koa from 'koa';
 import config from '../../../config';
 import { ILocalUser } from '../../../models/user';
 
-export default function(ctx: Koa.Context, user: ILocalUser, redirect = false) {
+export default function(ctx: Koa.BaseContext, user: ILocalUser, redirect = false) {
 	if (redirect) {
 		//#region Cookie
 		const expires = 1000 * 60 * 60 * 24 * 365; // One Year
diff --git a/src/server/api/private/signin.ts b/src/server/api/private/signin.ts
index 0a0f9ae6f..629252784 100644
--- a/src/server/api/private/signin.ts
+++ b/src/server/api/private/signin.ts
@@ -7,7 +7,7 @@ import { publishMainStream } from '../../../stream';
 import signin from '../common/signin';
 import config from '../../../config';
 
-export default async (ctx: Koa.Context) => {
+export default async (ctx: Koa.BaseContext) => {
 	ctx.set('Access-Control-Allow-Origin', config.url);
 	ctx.set('Access-Control-Allow-Credentials', 'true');
 
diff --git a/src/server/api/private/signup.ts b/src/server/api/private/signup.ts
index 8766a4f2d..b89629bcd 100644
--- a/src/server/api/private/signup.ts
+++ b/src/server/api/private/signup.ts
@@ -9,7 +9,7 @@ import RegistrationTicket from '../../../models/registration-tickets';
 import usersChart from '../../../chart/users';
 import fetchMeta from '../../../misc/fetch-meta';
 
-export default async (ctx: Koa.Context) => {
+export default async (ctx: Koa.BaseContext) => {
 	const body = ctx.request.body as any;
 
 	const instance = await fetchMeta();
diff --git a/src/server/api/service/discord.ts b/src/server/api/service/discord.ts
index d90f39ffb..1118e241d 100644
--- a/src/server/api/service/discord.ts
+++ b/src/server/api/service/discord.ts
@@ -10,11 +10,11 @@ import uuid = require('uuid');
 import signin from '../common/signin';
 import fetchMeta from '../../../misc/fetch-meta';
 
-function getUserToken(ctx: Koa.Context) {
+function getUserToken(ctx: Koa.BaseContext) {
 	return ((ctx.headers['cookie'] || '').match(/i=(!\w+)/) || [null, null])[1];
 }
 
-function compareOrigin(ctx: Koa.Context) {
+function compareOrigin(ctx: Koa.BaseContext) {
 	function normalizeUrl(url: string) {
 		return url ? url.endsWith('/') ? url.substr(0, url.length - 1) : url : '';
 	}
diff --git a/src/server/api/service/github.ts b/src/server/api/service/github.ts
index 4dce856c2..5934e96f6 100644
--- a/src/server/api/service/github.ts
+++ b/src/server/api/service/github.ts
@@ -10,11 +10,11 @@ import uuid = require('uuid');
 import signin from '../common/signin';
 import fetchMeta from '../../../misc/fetch-meta';
 
-function getUserToken(ctx: Koa.Context) {
+function getUserToken(ctx: Koa.BaseContext) {
 	return ((ctx.headers['cookie'] || '').match(/i=(!\w+)/) || [null, null])[1];
 }
 
-function compareOrigin(ctx: Koa.Context) {
+function compareOrigin(ctx: Koa.BaseContext) {
 	function normalizeUrl(url: string) {
 		return url ? url.endsWith('/') ? url.substr(0, url.length - 1) : url : '';
 	}
diff --git a/src/server/api/service/twitter.ts b/src/server/api/service/twitter.ts
index ced3e8acc..ff7f98527 100644
--- a/src/server/api/service/twitter.ts
+++ b/src/server/api/service/twitter.ts
@@ -9,11 +9,11 @@ import config from '../../../config';
 import signin from '../common/signin';
 import fetchMeta from '../../../misc/fetch-meta';
 
-function getUserToken(ctx: Koa.Context) {
+function getUserToken(ctx: Koa.BaseContext) {
 	return ((ctx.headers['cookie'] || '').match(/i=(!\w+)/) || [null, null])[1];
 }
 
-function compareOrigin(ctx: Koa.Context) {
+function compareOrigin(ctx: Koa.BaseContext) {
 	function normalizeUrl(url: string) {
 		return url.endsWith('/') ? url.substr(0, url.length - 1) : url;
 	}
diff --git a/src/server/file/send-drive-file.ts b/src/server/file/send-drive-file.ts
index c64177d4e..05d871a4c 100644
--- a/src/server/file/send-drive-file.ts
+++ b/src/server/file/send-drive-file.ts
@@ -7,12 +7,12 @@ import DriveFileWebpublic, { getDriveFileWebpublicBucket } from '../../models/dr
 
 const assets = `${__dirname}/../../server/file/assets/`;
 
-const commonReadableHandlerGenerator = (ctx: Koa.Context) => (e: Error): void => {
+const commonReadableHandlerGenerator = (ctx: Koa.BaseContext) => (e: Error): void => {
 	console.error(e);
 	ctx.status = 500;
 };
 
-export default async function(ctx: Koa.Context) {
+export default async function(ctx: Koa.BaseContext) {
 	// Validate id
 	if (!mongodb.ObjectID.isValid(ctx.params.id)) {
 		ctx.throw(400, 'incorrect id');
@@ -26,13 +26,13 @@ export default async function(ctx: Koa.Context) {
 
 	if (file == null) {
 		ctx.status = 404;
-		await send(ctx, '/dummy.png', { root: assets });
+		await send(ctx as any, '/dummy.png', { root: assets });
 		return;
 	}
 
 	if (file.metadata.deletedAt) {
 		ctx.status = 410;
-		await send(ctx, '/tombstone.png', { root: assets });
+		await send(ctx as any, '/tombstone.png', { root: assets });
 		return;
 	}
 
diff --git a/src/server/web/docs.ts b/src/server/web/docs.ts
index f9991fc65..94c18d999 100644
--- a/src/server/web/docs.ts
+++ b/src/server/web/docs.ts
@@ -160,7 +160,7 @@ const extractPropDefRef = (props: any[]) => {
 const router = new Router();
 
 router.get('/assets/*', async ctx => {
-	await send(ctx, ctx.params[0], {
+	await send(ctx as any, ctx.params[0], {
 		root: `${__dirname}/../../docs/assets/`,
 		maxage: ms('1 days')
 	});
diff --git a/src/server/web/index.ts b/src/server/web/index.ts
index 945176afd..69f3b8859 100644
--- a/src/server/web/index.ts
+++ b/src/server/web/index.ts
@@ -51,7 +51,7 @@ const router = new Router();
 //#region static assets
 
 router.get('/assets/*', async ctx => {
-	await send(ctx, ctx.path, {
+	await send(ctx as any, ctx.path, {
 		root: client,
 		maxage: ms('7 days'),
 		immutable: true
@@ -60,21 +60,21 @@ router.get('/assets/*', async ctx => {
 
 // Apple touch icon
 router.get('/apple-touch-icon.png', async ctx => {
-	await send(ctx, '/assets/apple-touch-icon.png', {
+	await send(ctx as any, '/assets/apple-touch-icon.png', {
 		root: client
 	});
 });
 
 // ServiceWorker
 router.get(/^\/sw\.(.+?)\.js$/, async ctx => {
-	await send(ctx, `/assets/sw.${ctx.params[0]}.js`, {
+	await send(ctx as any, `/assets/sw.${ctx.params[0]}.js`, {
 		root: client
 	});
 });
 
 // Manifest
 router.get('/manifest.json', async ctx => {
-	await send(ctx, '/assets/manifest.json', {
+	await send(ctx as any, '/assets/manifest.json', {
 		root: client
 	});
 });
diff --git a/src/server/web/url-preview.ts b/src/server/web/url-preview.ts
index 86ae3fa0a..4cda5ecb0 100644
--- a/src/server/web/url-preview.ts
+++ b/src/server/web/url-preview.ts
@@ -3,7 +3,7 @@ import * as request from 'request-promise-native';
 import summaly from 'summaly';
 import fetchMeta from '../../misc/fetch-meta';
 
-module.exports = async (ctx: Koa.Context) => {
+module.exports = async (ctx: Koa.BaseContext) => {
 	const meta = await fetchMeta();
 
 	try {