diff --git a/.config/example.yml b/.config/example.yml
index 0f38e593b6..ea83f9cfb8 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -60,11 +60,6 @@ mongodb:
   user: example-misskey-user
   pass: example-misskey-pass
 
-redis:
-  host: localhost
-  port: 6379
-  pass: example-pass
-
 # Drive capacity of a local user (MB)
 localDriveCapacityMb: 256
 
@@ -122,47 +117,50 @@ drive:
 # Below settings are optional
 #
 
+# Redis
+#redis:
+#  host: localhost
+#  port: 6379
+#  pass: example-pass
+
 # Elasticsearch
-# elasticsearch:
-#   host: localhost
-#   port: 9200
-#   pass: null
+#elasticsearch:
+#  host: localhost
+#  port: 9200
+#  pass: null
 
 # reCAPTCHA
-# recaptcha:
-#   site_key: example-site-key
+#recaptcha:
+#  site_key: example-site-key
 #  secret_key: example-secret-key
 
 # ServiceWorker
-# sw:
-#   # Public key of VAPID
-#   public_key: example-sw-public-key
-
-#   # Private key of VAPID
-#   private_key: example-sw-private-key
-
-# google_maps_api_key: example-google-maps-api-key
+#sw:
+#  # Public key of VAPID
+#  public_key: example-sw-public-key
+#
+#  # Private key of VAPID
+#  private_key: example-sw-private-key
 
 # Twitter integration
 # You need to set the oauth callback url as : https://<your-misskey-instance>/api/tw/cb
-# twitter:
-#   consumer_key: example-twitter-consumer-key
-#   consumer_secret: example-twitter-consumer-secret-key
+#twitter:
+#  consumer_key: example-twitter-consumer-key
+#  consumer_secret: example-twitter-consumer-secret-key
 
 # Ghost
 # Ghost account is an account used for the purpose of delegating
 # followers when putting users in the list.
-# ghost: user-id-of-your-ghost-account
+#ghost: user-id-of-your-ghost-account
 
 # Clustering
-# clusterLimit: 1
+#clusterLimit: 1
 
 # Summaly proxy
-# summalyProxy: "http://example.com"
+#summalyProxy: "http://example.com"
 
 # User recommendation
-user_recommendation:
-  external: true
-  engine: http://vinayaka.distsn.org/cgi-bin/vinayaka-user-match-misskey-api.cgi?{{host}}+{{user}}+{{limit}}+{{offset}}
-  timeout: 300000
-
+#user_recommendation:
+#  external: true
+#  engine: http://vinayaka.distsn.org/cgi-bin/vinayaka-user-match-misskey-api.cgi?{{host}}+{{user}}+{{limit}}+{{offset}}
+#  timeout: 300000
diff --git a/docs/setup.en.md b/docs/setup.en.md
index 23bcdcca98..e30297962b 100644
--- a/docs/setup.en.md
+++ b/docs/setup.en.md
@@ -24,12 +24,12 @@ Please install and setup these softwares:
 #### Dependencies :package:
 * **[Node.js](https://nodejs.org/en/)**
 * **[MongoDB](https://www.mongodb.com/)** >= 3.6
-* **[Redis](https://redis.io/)**
 
 ##### Optional
+* [Redis](https://redis.io/)
+  * Redis is optional, but we strongly recommended to install it
 * [Elasticsearch](https://www.elastic.co/) - used to provide searching feature instead of MongoDB
 
-
 *3.* Setup MongoDB
 ----------------------------------------------------------------
 In root :
diff --git a/docs/setup.ja.md b/docs/setup.ja.md
index e1ed63cab4..df98e6a8c0 100644
--- a/docs/setup.ja.md
+++ b/docs/setup.ja.md
@@ -24,9 +24,11 @@ adduser --disabled-password --disabled-login misskey
 #### 依存関係 :package:
 * **[Node.js](https://nodejs.org/en/)**
 * **[MongoDB](https://www.mongodb.com/)** (3.6以上)
-* **[Redis](https://redis.io/)**
 
 ##### オプション
+* [Redis](https://redis.io/)
+  * Redisはオプションですが、インストールすることを強く推奨します。
+	* インストールしなくていいのは、あなたのインスタンスが自分専用のときだけです
 * [Elasticsearch](https://www.elastic.co/) - 検索機能を向上させるために用います。
 
 *3.* MongoDBの設定
diff --git a/src/config/types.ts b/src/config/types.ts
index 5c7b8260db..5c2b554285 100644
--- a/src/config/types.ts
+++ b/src/config/types.ts
@@ -93,11 +93,9 @@ export type Source = {
 		private_key: string;
 	};
 
-	google_maps_api_key: string;
-
 	clusterLimit?: number;
 
-	user_recommendation: {
+	user_recommendation?: {
 		external: boolean;
 		engine: string;
 		timeout: number;
diff --git a/src/db/redis.ts b/src/db/redis.ts
index f8d66ebda0..48e3f4e43e 100644
--- a/src/db/redis.ts
+++ b/src/db/redis.ts
@@ -1,10 +1,10 @@
 import * as redis from 'redis';
 import config from '../config';
 
-export default redis.createClient(
+export default config.redis ? redis.createClient(
 	config.redis.port,
 	config.redis.host,
 	{
 		auth_pass: config.redis.pass
 	}
-);
+) : null;
diff --git a/src/server/api/limitter.ts b/src/server/api/limitter.ts
index 20a18a7098..abf7627ab8 100644
--- a/src/server/api/limitter.ts
+++ b/src/server/api/limitter.ts
@@ -8,6 +8,12 @@ import { IUser } from '../../models/user';
 const log = debug('misskey:limitter');
 
 export default (endpoint: IEndpoint, user: IUser) => new Promise((ok, reject) => {
+	// Redisがインストールされてない場合は常に許可
+	if (limiterDB == null) {
+		ok();
+		return;
+	}
+
 	const limitation = endpoint.meta.limit;
 
 	const key = limitation.hasOwnProperty('key')
diff --git a/src/server/api/service/twitter.ts b/src/server/api/service/twitter.ts
index f71e588628..6c3cdaa138 100644
--- a/src/server/api/service/twitter.ts
+++ b/src/server/api/service/twitter.ts
@@ -55,7 +55,7 @@ router.get('/disconnect/twitter', async ctx => {
 	}));
 });
 
-if (config.twitter == null) {
+if (config.twitter == null || redis == null) {
 	router.get('/connect/twitter', ctx => {
 		ctx.body = '現在Twitterへ接続できません (このインスタンスではTwitterはサポートされていません)';
 	});