diff --git a/lib/Controller/MessagesController.php b/lib/Controller/MessagesController.php
index 88b6299e21..f0f037ff89 100755
--- a/lib/Controller/MessagesController.php
+++ b/lib/Controller/MessagesController.php
@@ -30,11 +30,14 @@
 use OCA\Mail\Service\AccountService;
 use OCA\Mail\Service\AiIntegrations\AiIntegrationsService;
 use OCA\Mail\Service\ItineraryService;
+use OCA\Mail\Service\MessageOperationService;
 use OCA\Mail\Service\SmimeService;
 use OCA\Mail\Service\SnoozeService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\Attribute\FrontpageRoute;
+use OCP\AppFramework\Http\Attribute\NoAdminRequired;
 use OCP\AppFramework\Http\Attribute\OpenAPI;
 use OCP\AppFramework\Http\ContentSecurityPolicy;
 use OCP\AppFramework\Http\JSONResponse;
@@ -74,7 +77,8 @@ class MessagesController extends Controller {
 	private SnoozeService $snoozeService;
 	private AiIntegrationsService $aiIntegrationService;
 
-	public function __construct(string $appName,
+	public function __construct(
+		string $appName,
 		IRequest $request,
 		AccountService $accountService,
 		IMailManager $mailManager,
@@ -94,7 +98,9 @@ public function __construct(string $appName,
 		IDkimService $dkimService,
 		IUserPreferences $preferences,
 		SnoozeService $snoozeService,
-		AiIntegrationsService $aiIntegrationService) {
+		AiIntegrationsService $aiIntegrationService,
+		private MessageOperationService $messageOperationService,
+	) {
 		parent::__construct($appName, $request);
 		$this->accountService = $accountService;
 		$this->mailManager = $mailManager;
@@ -782,6 +788,24 @@ public function setFlags(int $id, array $flags): JSONResponse {
 		return new JSONResponse();
 	}
 
+	/**
+	 *
+	 * @NoAdminRequired
+	 *
+	 * @param array<int,int> $identifiers
+	 * @param array<int,string> $flags
+	 *
+	 * @return JSONResponse
+	 */
+	#[FrontpageRoute(verb: 'PUT', url: '/api/messages/flags')]
+	#[NoAdminRequired]
+	#[TrapError]
+	public function changeFlags(array $identifiers, array $flags): JSONResponse {
+		return new JSONResponse(
+			$this->messageOperationService->changeFlags($this->currentUserId, $identifiers, $flags)
+		);
+	}
+
 	/**
 	 * @NoAdminRequired
 	 *
diff --git a/lib/Db/MailAccountMapper.php b/lib/Db/MailAccountMapper.php
index 0e41bbe976..78821b5dfc 100644
--- a/lib/Db/MailAccountMapper.php
+++ b/lib/Db/MailAccountMapper.php
@@ -66,6 +66,25 @@ public function findById(int $id): MailAccount {
 		return $this->findEntity($query);
 	}
 
+	/**
+	 * Finds all mail accounts by account ids
+	 *
+	 * @param array<int,int> $identifiers
+	 *
+	 * @return array<int,MailAccount>
+	 */
+	public function findByIds(array $identifiers): array {
+		
+		$cmd = $this->db->getQueryBuilder();
+		$cmd->select('*')
+			->from($this->getTableName())
+			->where(
+				$cmd->expr()->in('id', $cmd->createNamedParameter($identifiers, IQueryBuilder::PARAM_STR_ARRAY), IQueryBuilder::PARAM_STR_ARRAY)
+			);
+
+		return $this->findEntities($cmd);
+	}
+
 	/**
 	 * Finds all Mail Accounts by user id existing for this user
 	 *
diff --git a/lib/Db/MailboxMapper.php b/lib/Db/MailboxMapper.php
index 434c63fd10..3e316d4eb3 100644
--- a/lib/Db/MailboxMapper.php
+++ b/lib/Db/MailboxMapper.php
@@ -113,7 +113,9 @@ public function findById(int $id): Mailbox {
 	}
 
 	/**
-	 * @return Mailbox[]
+	 * @param array<string> $ids
+	 *
+	 * @return array<Mailbox>
 	 *
 	 * @throws Exception
 	 */
diff --git a/lib/Db/MessageMapper.php b/lib/Db/MessageMapper.php
index cdc0e71870..d8a637fbc1 100644
--- a/lib/Db/MessageMapper.php
+++ b/lib/Db/MessageMapper.php
@@ -178,6 +178,28 @@ public function findUidsForIds(Mailbox $mailbox, array $ids) {
 		}, array_chunk($ids, 1000));
 	}
 
+	/**
+	 * @param array<int,int> $identifiers
+	 *
+	 * @return array
+	 */
+	public function findMailboxAndUid(array $identifiers): array {
+		
+		if ($identifiers === []) {
+			return [];
+		}
+
+		$cmd = $this->db->getQueryBuilder();
+		$cmd->select('id', 'mailbox_id', 'uid')
+			->from($this->getTableName())
+			->where(
+				$cmd->expr()->in('id', $cmd->createNamedParameter($identifiers, IQueryBuilder::PARAM_STR_ARRAY), IQueryBuilder::PARAM_STR_ARRAY)
+			);
+
+		return $cmd->executeQuery()->fetchAll();
+		
+	}
+
 	/**
 	 * @param Account $account
 	 *
diff --git a/lib/IMAP/MessageMapper.php b/lib/IMAP/MessageMapper.php
index f076d6f4f4..e3281ae45d 100644
--- a/lib/IMAP/MessageMapper.php
+++ b/lib/IMAP/MessageMapper.php
@@ -435,6 +435,44 @@ public function removeFlag(Horde_Imap_Client_Socket $client,
 		);
 	}
 
+	/**
+	 * @throws Horde_Imap_Client_Exception
+	 */
+	public function setFlags(
+		Horde_Imap_Client_Socket $client,
+		Mailbox $mailbox,
+		array $uids,
+		array $addFlags = [],
+		array $removeFlags = [],
+		array $replaceFlags = [],
+	): array {
+
+		if (count($uids) === 0) {
+			return [];
+		}
+
+		$cmd = [];
+		
+		if (count($replaceFlags) > 0) {
+			$cmd['replace'] = $replaceFlags;
+		} else {
+			if (count($addFlags) > 0) {
+				$cmd['add'] = $addFlags;
+			}
+			if (count($removeFlags) > 0) {
+				$cmd['remove'] = $removeFlags;
+			}
+		}
+
+		if (count($cmd) > 0) {
+			$cmd['ids'] = new Horde_Imap_Client_Ids($uids);
+			$result = $client->store($mailbox->getName(), $cmd);
+			return $result->ids;
+		}
+
+		return [];
+	}
+	
 	/**
 	 * @param Horde_Imap_Client_Socket $client
 	 * @param Mailbox $mailbox
diff --git a/lib/Service/MessageOperationService.php b/lib/Service/MessageOperationService.php
new file mode 100644
index 0000000000..c1e6e8000e
--- /dev/null
+++ b/lib/Service/MessageOperationService.php
@@ -0,0 +1,153 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Mail\Service;
+
+use OCA\Mail\Account;
+use OCA\Mail\Db\MailAccountMapper;
+use OCA\Mail\Db\MailboxMapper;
+use OCA\Mail\Db\MessageMapper;
+use OCA\Mail\IMAP\IMAPClientFactory;
+use OCA\Mail\IMAP\MessageMapper as ImapMessageMapper;
+use Throwable;
+
+class MessageOperationService {
+
+	public function __construct(
+		protected IMAPClientFactory $clientFactory,
+		protected MailAccountMapper $accountMapper,
+		protected MailboxMapper $mailboxMapper,
+		protected MessageMapper $messageMapper,
+		protected MailManager $mailManager,
+		protected ImapMessageMapper $imapMessageMapper,
+	) {
+	}
+
+	/**
+	 * convert message collection to grouped collections by mailbox id
+	 *
+	 * [[mailbox_id, uid, id]] to [mailbox_id => [[id, uid]]]
+	 *
+	 * @param array<array{0:int,1:int,2:int}> $collection
+	 *
+	 * @return array<int,array<array{0:int,1:int}>>
+	 */
+	protected function groupByMailbox(array $collection): array {
+		return array_reduce($collection, function ($carry, $pair) {
+			if (!isset($carry[$pair['mailbox_id']])) {
+				$carry[$pair['mailbox_id']] = [];
+			}
+			$carry[$pair['mailbox_id']][] = ['id' => $pair['id'], 'uid' => $pair['uid']];
+			return $carry;
+		}, []);
+	}
+
+	/**
+	 * convert mailbox collection to grouped collections by account id
+	 *
+	 * [mailbox] to [account_id => [mailbox]]
+	 *
+	 * @param array<\OCA\Mail\Db\MailBox> $collection
+	 *
+	 * @return array<int,array<\OCA\Mail\Db\MailBox>>
+	 */
+	protected function groupByAccount(array $collection) {
+		return array_reduce($collection, function ($carry, $entry) {
+			if (!isset($carry[$entry->getAccountId()])) {
+				$carry[$entry->getAccountId()] = [];
+			}
+			$carry[$entry->getAccountId()][] = $entry;
+			return $carry;
+		}, []);
+	}
+
+	/**
+	 * generates operation status responses for each message
+	 *
+	 * @param array<int,bool> &$results
+	 * @param bool $value
+	 * @param array<\OCA\Mail\Db\MailBox> $mailboxes
+	 * @param array<int,array<array{0:int,1:int}>> $messages
+	 */
+	protected function generateResult(array &$results, bool $value, array $mailboxes, array $messages) {
+		foreach ($mailboxes as $mailbox) {
+			foreach ($messages[$mailbox->getId()] as $message) {
+				$results[$message['id']] = $value;
+			}
+		}
+	}
+
+	/**
+	 * Set/Unset system flags or keywords
+	 *
+	 * @param string $userId system user id
+	 * @param array<int> $identifiers message ids
+	 * @param array<string,bool> $flags message flags
+	 *
+	 * @return array<int,bool> operation results
+	 */
+	public function changeFlags(string $userId, array $identifiers, array $flags): array {
+
+		// retrieve message meta data [uid, mailbox_id] for all messages and group by mailbox id
+		$messages = $this->groupByMailbox($this->messageMapper->findMailboxAndUid($identifiers));
+		// retrieve all mailboxes and group by account
+		$mailboxes = $this->groupByAccount($this->mailboxMapper->findByIds(array_keys($messages)));
+		// retrieve all accounts
+		$accounts = $this->accountMapper->findByIds(array_keys($mailboxes));
+		// process every account
+		$results = [];
+		foreach ($accounts as $account) {
+			$account = new Account($account);
+			// determine if account belongs to the user and skip if not
+			if ($account->getUserId() != $userId) {
+				// add messages to results as failed
+				$this->generateResult($results, false, $mailboxes[$account->getId()], $messages);
+				continue;
+			}
+			$client = $this->clientFactory->getClient($account);
+			// process every mailbox
+			foreach ($mailboxes[$account->getId()] as $mailbox) {
+				try {
+					// check if specific flags are supported and group them by action
+					$addFlags = [];
+					$removeFlags = [];
+					foreach ($flags as $flag => $value) {
+						$value = filter_var($value, FILTER_VALIDATE_BOOLEAN);
+						$imapFlags = $this->mailManager->filterFlags($client, $account, $flag, $mailbox->getName());
+						if (empty($imapFlags)) {
+							continue;
+						}
+						if ($value) {
+							$addFlags = array_merge($addFlags, $imapFlags);
+						} else {
+							$removeFlags = array_merge($removeFlags, $imapFlags);
+						}
+					}
+					// apply flags to messages on server
+					$this->imapMessageMapper->setFlags(
+						$client,
+						$mailbox,
+						array_column($messages[$mailbox->getId()], 'uid'),
+						$addFlags,
+						$removeFlags
+					);
+					// add messages to results as successful
+					$this->generateResult($results, true, [$mailbox], $messages);
+				} catch (Throwable $e) {
+					// add messages to results as failed
+					$this->generateResult($results, false, [$mailbox], $messages);
+				}
+			}
+			$client->logout();
+		}
+		
+		return $results;
+	}
+
+}
diff --git a/src/components/EnvelopeList.vue b/src/components/EnvelopeList.vue
index 253678177e..e2b56f66ed 100644
--- a/src/components/EnvelopeList.vue
+++ b/src/components/EnvelopeList.vue
@@ -67,7 +67,7 @@
 						}}
 					</ActionButton>
 					<ActionButton :close-after-click="true"
-						@click.prevent="favoriteOrUnfavoriteAll">
+						@click.prevent="markSelectedFavoriteOrUnfavorite">
 						<template #icon>
 							<IconFavorite :size="16" />
 						</template>
@@ -414,12 +414,11 @@ export default {
 			return this.selection.includes(idx)
 		},
 		markSelectedSeenOrUnseen() {
-			const seen = !this.areAllSelectedRead
-			this.selectedEnvelopes.forEach((envelope) => {
-				this.$store.dispatch('toggleEnvelopeSeen', {
-					envelope,
-					seen,
-				})
+			const state = !this.areAllSelectedRead
+			const envelopes = this.selectedEnvelopes
+			this.$store.dispatch('markEnvelopesSeenOrUnseen', {
+				envelopes,
+				state,
 			})
 			this.unselectAll()
 		},
@@ -442,6 +441,14 @@ export default {
 			this.unselectAll()
 		},
 		async markSelectionJunk() {
+			const state = true
+			const envelopes = this.selectedEnvelopes
+			this.$store.dispatch('markEnvelopesJunkOrNotJunk', {
+				envelopes,
+				state,
+			})
+			this.unselectAll()
+			/*
 			for (const envelope of this.selectedEnvelopes) {
 				if (!envelope.flags.$junk) {
 					await this.$store.dispatch('toggleEnvelopeJunk', {
@@ -451,8 +458,17 @@ export default {
 				}
 			}
 			this.unselectAll()
+			*/
 		},
 		async markSelectionNotJunk() {
+			const state = false
+			const envelopes = this.selectedEnvelopes
+			this.$store.dispatch('markEnvelopesJunkOrNotJunk', {
+				envelopes,
+				state,
+			})
+			this.unselectAll()
+			/*
 			for (const envelope of this.selectedEnvelopes) {
 				if (envelope.flags.$junk) {
 					await this.$store.dispatch('toggleEnvelopeJunk', {
@@ -462,14 +478,14 @@ export default {
 				}
 			}
 			this.unselectAll()
-		},
-		favoriteOrUnfavoriteAll() {
-			const favFlag = !this.areAllSelectedFavorite
-			this.selectedEnvelopes.forEach((envelope) => {
-				this.$store.dispatch('markEnvelopeFavoriteOrUnfavorite', {
-					envelope,
-					favFlag,
-				})
+			*/
+		},
+		markSelectedFavoriteOrUnfavorite() {
+			const state = !this.areAllSelectedFavorite
+			const envelopes = this.selectedEnvelopes
+			this.$store.dispatch('markEnvelopesFavoriteOrUnfavorite', {
+				envelopes,
+				state,
 			})
 			this.unselectAll()
 		},
diff --git a/src/service/MessageService.js b/src/service/MessageService.js
index 7ee429e576..fd4a391b10 100644
--- a/src/service/MessageService.js
+++ b/src/service/MessageService.js
@@ -115,15 +115,14 @@ export async function clearCache(accountId, id) {
 /**
  * Set flags for envelope
  *
- * @param {int} id
+ * @param {array} identifiers
  * @param {object} flags
  */
-export async function setEnvelopeFlags(id, flags) {
-	const url = generateUrl('/apps/mail/api/messages/{id}/flags', {
-		id,
-	})
+export async function setEnvelopeFlags(identifiers, flags) {
+	const url = generateUrl('/apps/mail/api/messages/flags')
 
 	return await axios.put(url, {
+		identifiers,
 		flags,
 	})
 }
diff --git a/src/store/actions.js b/src/store/actions.js
index a6324b58cf..26374d0db2 100644
--- a/src/store/actions.js
+++ b/src/store/actions.js
@@ -912,7 +912,7 @@ export default {
 			})
 
 			try {
-				await setEnvelopeFlags(envelope.databaseId, {
+				await setEnvelopeFlags([ envelope.databaseId ], {
 					flagged: !oldState,
 				})
 			} catch (error) {
@@ -960,8 +960,8 @@ export default {
 			})
 
 			try {
-				await setEnvelopeFlags(envelope.databaseId, {
-					seen: newState,
+				await setEnvelopeFlags([ envelope.databaseId ], { 
+					seen: newState
 				})
 			} catch (error) {
 				console.error('could not toggle message seen state', error)
@@ -997,7 +997,7 @@ export default {
 			}
 
 			try {
-				await setEnvelopeFlags(envelope.databaseId, {
+				await setEnvelopeFlags([ envelope.databaseId ], {
 					$junk: !oldState,
 					$notjunk: oldState,
 				})
@@ -1024,32 +1024,72 @@ export default {
 			}
 		})
 	},
-	async markEnvelopeFavoriteOrUnfavorite({ commit, getters }, { envelope, favFlag }) {
+	async markEnvelopesSeenOrUnseen({ commit, getters }, { envelopes, state }) {
 		return handleHttpAuthErrors(commit, async () => {
-			// Change immediately and switch back on error
-			const oldState = envelope.flags.flagged
-			commit('flagEnvelope', {
-				envelope,
-				flag: 'flagged',
-				value: favFlag,
+			try {
+				const identifiers = []
+				envelopes.forEach((envelope) => {
+					identifiers.push(envelope.databaseId)
+				})
+				await setEnvelopeFlags(identifiers, { seen: state })
+			} catch (error) {
+				console.error('could not mark messages seen or unseen', error)
+				throw error
+			}
+			envelopes.forEach((envelope) => {
+				commit('flagEnvelope', {
+					envelope,
+					flag: 'seen',
+					value: state,
+				})
 			})
-
+		})
+	},
+	async markEnvelopesJunkOrNotJunk({ commit, getters }, { envelopes, state }) {
+		return handleHttpAuthErrors(commit, async () => {
 			try {
-				await setEnvelopeFlags(envelope.databaseId, {
-					flagged: favFlag,
+				const identifiers = []
+				envelopes.forEach((envelope) => {
+					identifiers.push(envelope.databaseId)
 				})
+				await setEnvelopeFlags(identifiers, { junk: state, notjunk: !state })
 			} catch (error) {
-				console.error('could not favorite/unfavorite message ' + envelope.uid, error)
-
-				// Revert change
+				console.error('could not mark messages junk or not junk', error)
+				throw error
+			}
+			envelopes.forEach((envelope) => {
 				commit('flagEnvelope', {
 					envelope,
-					flag: 'flagged',
-					value: oldState,
+					flag: '$junk',
+					value: state,
 				})
-
+				commit('flagEnvelope', {
+					envelope,
+					flag: '$notjunk',
+					value: !state,
+				})
+			})
+		})
+	},
+	async markEnvelopesFavoriteOrUnfavorite({ commit, getters }, { envelopes, state }) {
+		return handleHttpAuthErrors(commit, async () => {
+			try {
+				const identifiers = []
+				envelopes.forEach((envelope) => {
+					identifiers.push(envelope.databaseId)
+				})
+				await setEnvelopeFlags(identifiers, { flagged: state })
+			} catch (error) {
+				console.error('could not mark messages favorite or unfavorite', error)
 				throw error
 			}
+			envelopes.forEach((envelope) => {
+				commit('flagEnvelope', {
+					envelope,
+					flag: 'flagged',
+					value: state,
+				})
+			})
 		})
 	},
 	async markEnvelopeImportantOrUnimportant({ commit, dispatch, getters }, { envelope, addTag }) {
diff --git a/vite.config.js b/vite.config.js
index 789c28a71a..40f2edf9fb 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -22,6 +22,7 @@ export default createAppConfig({
 	config: {
 		build: {
 			cssCodeSplit: false,
+			minify: false,
 		},
 		plugins: [
 			ckeditor5({ theme: require.resolve('@ckeditor/ckeditor5-theme-lark') }),