diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index a7796c4d11..f644c9e658 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -870,9 +870,6 @@ desktop/views/components/settings.vue:
   web-search-engine-desc: "例: https://www.google.com/?#q={{query}}"
   auto-popout: "ウィンドウの自動ポップアウト"
   auto-popout-desc: "ウィンドウが開かれるとき、ポップアウト(ブラウザ外に切り離す)可能なら自動でポップアウトします。この設定はブラウザに記憶されます。"
-  advanced: "詳細設定"
-  api-via-stream: "ストリームを経由したAPIリクエスト"
-  api-via-stream-desc: "この設定をオンにすると、websocket接続を経由してAPIリクエストが行われます(パフォーマンス向上が期待できます)。オフにすると、ネイティブの fetch APIが利用されます。この設定はこのデバイスのみ有効です。"
   deck-nav: "デッキ内ナビゲーション"
   deck-nav-desc: "デッキを使用しているとき、ナビゲーションが発生する際にページ遷移を行わずに一時的なカラムで受けるようにします。"
   deck-default: "デッキをデフォルトのUIにする"
diff --git a/src/client/app/admin/views/dashboard.vue b/src/client/app/admin/views/dashboard.vue
index 9fb97f2ef9..aa4431e438 100644
--- a/src/client/app/admin/views/dashboard.vue
+++ b/src/client/app/admin/views/dashboard.vue
@@ -148,7 +148,7 @@ export default Vue.extend({
 		},
 
 		updateStats() {
-			this.$root.api('stats', {}, false, true).then(stats => {
+			this.$root.api('stats', {}, true).then(stats => {
 				this.stats = stats;
 			});
 		}
diff --git a/src/client/app/common/views/components/signin.vue b/src/client/app/common/views/components/signin.vue
index 7efbde38b2..724efdfc18 100644
--- a/src/client/app/common/views/components/signin.vue
+++ b/src/client/app/common/views/components/signin.vue
@@ -72,7 +72,7 @@ export default Vue.extend({
 				username: this.username,
 				password: this.password,
 				token: this.user && this.user.twoFactorEnabled ? this.token : undefined
-			}, true).then(res => {
+			}).then(res => {
 				localStorage.setItem('i', res.i);
 				location.reload();
 			}).catch(() => {
diff --git a/src/client/app/common/views/components/signup.vue b/src/client/app/common/views/components/signup.vue
index f7c4f4bf1e..f38aaad8ed 100644
--- a/src/client/app/common/views/components/signup.vue
+++ b/src/client/app/common/views/components/signup.vue
@@ -142,11 +142,11 @@ export default Vue.extend({
 				password: this.password,
 				invitationCode: this.invitationCode,
 				'g-recaptcha-response': this.meta.enableRecaptcha ? (window as any).grecaptcha.getResponse() : null
-			}, true).then(() => {
+			}).then(() => {
 				this.$root.api('signin', {
 					username: this.username,
 					password: this.password
-				}, true).then(res => {
+				}).then(res => {
 					localStorage.setItem('i', res.i);
 					location.reload();
 				});
diff --git a/src/client/app/desktop/views/components/settings.vue b/src/client/app/desktop/views/components/settings.vue
index 5ffe69ef45..78f8d9ccd2 100644
--- a/src/client/app/desktop/views/components/settings.vue
+++ b/src/client/app/desktop/views/components/settings.vue
@@ -32,13 +32,6 @@
 					<span slot="desc">{{ $t('auto-popout-desc') }}</span>
 				</ui-switch>
 				<ui-switch v-model="deckNav">{{ $t('deck-nav') }}<span slot="desc">{{ $t('deck-nav-desc') }}</span></ui-switch>
-
-				<details>
-					<summary>{{ $t('advanced') }}</summary>
-					<ui-switch v-model="apiViaStream">{{ $t('api-via-stream') }}
-						<span slot="desc">{{ $t('api-via-stream-desc') }}</span>
-					</ui-switch>
-				</details>
 			</section>
 
 			<section>
@@ -333,11 +326,6 @@ export default Vue.extend({
 			set(value) { this.$store.commit('device/set', { key: 'reduceMotion', value }); }
 		},
 
-		apiViaStream: {
-			get() { return this.$store.state.device.apiViaStream; },
-			set(value) { this.$store.commit('device/set', { key: 'apiViaStream', value }); }
-		},
-
 		autoPopout: {
 			get() { return this.$store.state.device.autoPopout; },
 			set(value) { this.$store.commit('device/set', { key: 'autoPopout', value }); }
diff --git a/src/client/app/mios.ts b/src/client/app/mios.ts
index fad60f4137..dc550b6f70 100644
--- a/src/client/app/mios.ts
+++ b/src/client/app/mios.ts
@@ -385,7 +385,7 @@ export default class MiOS extends EventEmitter {
 	 * @param data パラメータ
 	 */
 	@autobind
-	public api(endpoint: string, data: { [x: string]: any } = {}, forceFetch = false, silent = false): Promise<{ [x: string]: any }> {
+	public api(endpoint: string, data: { [x: string]: any } = {}, silent = false): Promise<{ [x: string]: any }> {
 		if (!silent) {
 			if (++pending === 1) {
 				spinner = document.createElement('div');
@@ -401,66 +401,44 @@ export default class MiOS extends EventEmitter {
 		};
 
 		const promise = new Promise((resolve, reject) => {
-			const viaStream = this.stream && this.stream.state == 'connected' && this.store.state.device.apiViaStream && !forceFetch;
+			// Append a credential
+			if (this.store.getters.isSignedIn) (data as any).i = this.store.state.i.token;
 
-			if (viaStream) {
-				const id = Math.random().toString().substr(2, 8);
+			const req = {
+				id: uuid(),
+				date: new Date(),
+				name: endpoint,
+				data,
+				res: null,
+				status: null
+			};
 
-				this.stream.once(`api:${id}`, res => {
-					if (res == null || Object.keys(res).length == 0) {
-						resolve(null);
-					} else if (res.res) {
-						resolve(res.res);
-					} else {
-						reject(res.e);
-					}
-				});
+			if (this.debug) {
+				this.requests.push(req);
+			}
 
-				this.stream.send('api', {
-					id: id,
-					ep: endpoint,
-					data: data
-				});
-			} else {
-				// Append a credential
-				if (this.store.getters.isSignedIn) (data as any).i = this.store.state.i.token;
-
-				const req = {
-					id: uuid(),
-					date: new Date(),
-					name: endpoint,
-					data,
-					res: null,
-					status: null
-				};
+			// Send request
+			fetch(endpoint.indexOf('://') > -1 ? endpoint : `${apiUrl}/${endpoint}`, {
+				method: 'POST',
+				body: JSON.stringify(data),
+				credentials: endpoint === 'signin' ? 'include' : 'omit',
+				cache: 'no-cache'
+			}).then(async (res) => {
+				const body = res.status === 204 ? null : await res.json();
 
 				if (this.debug) {
-					this.requests.push(req);
+					req.status = res.status;
+					req.res = body;
 				}
 
-				// Send request
-				fetch(endpoint.indexOf('://') > -1 ? endpoint : `${apiUrl}/${endpoint}`, {
-					method: 'POST',
-					body: JSON.stringify(data),
-					credentials: endpoint === 'signin' ? 'include' : 'omit',
-					cache: 'no-cache'
-				}).then(async (res) => {
-					const body = res.status === 204 ? null : await res.json();
-
-					if (this.debug) {
-						req.status = res.status;
-						req.res = body;
-					}
-
-					if (res.status === 200) {
-						resolve(body);
-					} else if (res.status === 204) {
-						resolve();
-					} else {
-						reject(body.error);
-					}
-				}).catch(reject);
-			}
+				if (res.status === 200) {
+					resolve(body);
+				} else if (res.status === 204) {
+					resolve();
+				} else {
+					reject(body.error);
+				}
+			}).catch(reject);
 		});
 
 		promise.then(onFinally, onFinally);
diff --git a/src/client/app/store.ts b/src/client/app/store.ts
index 03fc9565d8..350826e5ef 100644
--- a/src/client/app/store.ts
+++ b/src/client/app/store.ts
@@ -47,7 +47,6 @@ const defaultSettings = {
 
 const defaultDeviceSettings = {
 	reduceMotion: false,
-	apiViaStream: true,
 	autoPopout: false,
 	darkmode: false,
 	darkTheme: 'dark',