diff --git a/packages/frontend/src/components/MkAutocomplete.vue b/packages/frontend/src/components/MkAutocomplete.vue
index 43ce8bbb50..5af22867b1 100644
--- a/packages/frontend/src/components/MkAutocomplete.vue
+++ b/packages/frontend/src/components/MkAutocomplete.vue
@@ -46,6 +46,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts">
 import { markRaw, ref, shallowRef, computed, onUpdated, onMounted, onBeforeUnmount, nextTick, watch } from 'vue';
 import sanitizeHtml from 'sanitize-html';
+import { debounce } from 'throttle-debounce';
 import contains from '@/scripts/contains.js';
 import { char2twemojiFilePath, char2fluentEmojiFilePath } from '@/scripts/emoji-base.js';
 import { acct } from '@/filters/user.js';
@@ -189,6 +190,7 @@ const mfmTags = ref<string[]>([]);
 const mfmParams = ref<string[]>([]);
 const select = ref(-1);
 const zIndex = os.claimZIndex('high');
+const abortController = ref<AbortController>();
 
 function complete<T extends keyof CompleteInfo>(type: T, value: CompleteInfo[T]['payload']) {
 	emit('done', { type, value });
@@ -217,6 +219,39 @@ function setPosition() {
 	}
 }
 
+const searchUsers = debounce(1000, (query: string, cacheKey: string) => {
+	if (abortController.value) {
+		abortController.value.abort();
+	}
+	abortController.value = new AbortController();
+	misskeyApi('users/search-by-username-and-host', {
+		username: query,
+		limit: 10,
+		detail: false,
+	}, undefined, abortController.value.signal).then(searchedUsers => {
+		users.value = searchedUsers as any[];
+		fetching.value = false;
+		// キャッシュ
+		sessionStorage.setItem(cacheKey, JSON.stringify(searchedUsers));
+	});
+});
+
+const searchHashtags = debounce(1000, (query: string, cacheKey: string) => {
+	if (abortController.value) {
+		abortController.value.abort();
+	}
+	abortController.value = new AbortController();
+	misskeyApi('hashtags/search', {
+		query,
+		limit: 30,
+	}, undefined, abortController.value.signal).then(searchedHashtags => {
+		hashtags.value = searchedHashtags as any[];
+		fetching.value = false;
+		// キャッシュ
+		sessionStorage.setItem(cacheKey, JSON.stringify(searchedHashtags));
+	});
+});
+
 function exec() {
 	select.value = -1;
 	if (suggests.value) {
@@ -238,16 +273,7 @@ function exec() {
 			users.value = JSON.parse(cache);
 			fetching.value = false;
 		} else {
-			misskeyApi('users/search-by-username-and-host', {
-				username: props.q,
-				limit: 10,
-				detail: false,
-			}).then(searchedUsers => {
-				users.value = searchedUsers as any[];
-				fetching.value = false;
-				// キャッシュ
-				sessionStorage.setItem(cacheKey, JSON.stringify(searchedUsers));
-			});
+			searchUsers(props.q, cacheKey);
 		}
 	} else if (props.type === 'hashtag') {
 		if (!props.q || props.q === '') {
@@ -261,15 +287,7 @@ function exec() {
 				hashtags.value = hashtags;
 				fetching.value = false;
 			} else {
-				misskeyApi('hashtags/search', {
-					query: props.q,
-					limit: 30,
-				}).then(searchedHashtags => {
-					hashtags.value = searchedHashtags as any[];
-					fetching.value = false;
-					// キャッシュ
-					sessionStorage.setItem(cacheKey, JSON.stringify(searchedHashtags));
-				});
+				searchHashtags(props.q, cacheKey);
 			}
 		}
 	} else if (props.type === 'emoji') {
diff --git a/packages/frontend/src/components/MkSignin.vue b/packages/frontend/src/components/MkSignin.vue
index cc182a233a..4b8f6d45ca 100644
--- a/packages/frontend/src/components/MkSignin.vue
+++ b/packages/frontend/src/components/MkSignin.vue
@@ -11,7 +11,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			{{ message }}
 		</MkInfo>
 		<div v-if="!totpLogin" class="normal-signin _gaps_m">
-			<MkInput v-model="username" :placeholder="i18n.ts.username" type="text" pattern="^[a-zA-Z0-9_]+$" :spellcheck="false" autocomplete="username webauthn" autofocus required data-cy-signin-username @update:modelValue="onUsernameChange">
+			<MkInput v-model="username" :debounce="true" :placeholder="i18n.ts.username" type="text" pattern="^[a-zA-Z0-9_]+$" :spellcheck="false" autocomplete="username webauthn" autofocus required data-cy-signin-username @update:modelValue="onUsernameChange">
 				<template #prefix>@</template>
 				<template #suffix>@{{ host }}</template>
 			</MkInput>
@@ -19,7 +19,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<template #prefix><i class="ti ti-lock"></i></template>
 				<template #caption><button class="_textButton" type="button" @click="resetPassword">{{ i18n.ts.forgotPassword }}</button></template>
 			</MkInput>
-			<MkButton type="submit" large primary rounded :disabled="signing" style="margin: 0 auto;">{{ signing ? i18n.ts.loggingIn : i18n.ts.login }}</MkButton>
+			<MkButton type="submit" large primary rounded :disabled="!user || signing" style="margin: 0 auto;">{{ signing ? i18n.ts.loggingIn : i18n.ts.login }}</MkButton>
 		</div>
 		<div v-if="totpLogin" class="2fa-signin" :class="{ securityKeys: user && user.securityKeys }">
 			<div v-if="user && user.securityKeys" class="twofa-group tap-group">
@@ -64,6 +64,7 @@ import { login } from '@/account.js';
 import { i18n } from '@/i18n.js';
 
 const signing = ref(false);
+const userAbortController = ref<AbortController>();
 const user = ref<Misskey.entities.UserDetailed | null>(null);
 const username = ref('');
 const password = ref('');
@@ -97,9 +98,13 @@ const props = defineProps({
 });
 
 function onUsernameChange(): void {
+	if (userAbortController.value) {
+		userAbortController.value.abort();
+	}
+	userAbortController.value = new AbortController();
 	misskeyApi('users/show', {
 		username: username.value,
-	}).then(userResponse => {
+	}, undefined, userAbortController.value.signal).then(userResponse => {
 		user.value = userResponse;
 	}, () => {
 		user.value = null;
diff --git a/packages/frontend/src/components/MkUserSelectDialog.vue b/packages/frontend/src/components/MkUserSelectDialog.vue
index ab696ac1e5..9e057b7c42 100644
--- a/packages/frontend/src/components/MkUserSelectDialog.vue
+++ b/packages/frontend/src/components/MkUserSelectDialog.vue
@@ -16,16 +16,16 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<template #header>{{ i18n.ts.selectUser }}</template>
 	<div>
 		<div :class="$style.form">
-			<MkInput v-if="localOnly" v-model="username" :autofocus="true" @update:modelValue="search">
+			<MkInput v-if="localOnly" v-model="username" :debounce="true" :autofocus="true" @update:modelValue="search">
 				<template #label>{{ i18n.ts.username }}</template>
 				<template #prefix>@</template>
 			</MkInput>
 			<FormSplit v-else :minWidth="170">
-				<MkInput v-model="username" :autofocus="true" @update:modelValue="search">
+				<MkInput v-model="username" :debounce="true" :autofocus="true" @update:modelValue="search">
 					<template #label>{{ i18n.ts.username }}</template>
 					<template #prefix>@</template>
 				</MkInput>
-				<MkInput v-model="host" :datalist="[hostname]" @update:modelValue="search">
+				<MkInput v-model="host" :debounce="true" :datalist="[hostname]" @update:modelValue="search">
 					<template #label>{{ i18n.ts.host }}</template>
 					<template #prefix>@</template>
 				</MkInput>
@@ -92,18 +92,23 @@ const users = ref<Misskey.entities.UserLite[]>([]);
 const recentUsers = ref<Misskey.entities.UserDetailed[]>([]);
 const selected = ref<Misskey.entities.UserLite | null>(null);
 const dialogEl = ref();
+const abortController = ref<AbortController>();
 
 function search() {
+	if (abortController.value) {
+		abortController.value.abort();
+	}
 	if (username.value === '' && host.value === '') {
 		users.value = [];
 		return;
 	}
+	abortController.value = new AbortController();
 	misskeyApi('users/search-by-username-and-host', {
 		username: username.value,
 		host: props.localOnly ? '.' : host.value,
 		limit: 10,
 		detail: false,
-	}).then(_users => {
+	}, undefined, abortController.value.signal).then(_users => {
 		users.value = _users.filter((u) => {
 			if (props.includeSelf) {
 				return true;
diff --git a/packages/frontend/src/pages/api-console.vue b/packages/frontend/src/pages/api-console.vue
index 30f12a8fb3..3fe4f24af5 100644
--- a/packages/frontend/src/pages/api-console.vue
+++ b/packages/frontend/src/pages/api-console.vue
@@ -9,7 +9,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<MkSpacer :contentMax="700">
 		<div class="_gaps_m">
 			<div class="_gaps_m">
-				<MkInput v-model="endpoint" :datalist="endpoints" @update:modelValue="onEndpointChange()">
+				<MkInput v-model="endpoint" :debounce="true" :datalist="endpoints" @update:modelValue="onEndpointChange()">
 					<template #label>Endpoint</template>
 				</MkInput>
 				<MkTextarea v-model="body" code>
@@ -50,6 +50,7 @@ const endpoints = ref<string[]>([]);
 const sending = ref(false);
 const res = ref('');
 const withCredential = ref(true);
+const endpointAbortController = ref<AbortController>();
 
 misskeyApi('endpoints').then(endpointResponse => {
 	endpoints.value = endpointResponse;
@@ -68,7 +69,11 @@ function send() {
 }
 
 function onEndpointChange() {
-	misskeyApi('endpoint', { endpoint: endpoint.value }, withCredential.value ? undefined : null).then(resp => {
+	if (endpointAbortController.value) {
+		endpointAbortController.value.abort();
+	}
+	endpointAbortController.value = new AbortController();
+	misskeyApi('endpoint', { endpoint: endpoint.value }, withCredential.value ? undefined : null, endpointAbortController.value.signal).then(resp => {
 		const endpointBody = {};
 		for (const p of resp.params) {
 			endpointBody[p.name] =