diff --git a/composer.json b/composer.json
index 06b2c861..389f4584 100644
--- a/composer.json
+++ b/composer.json
@@ -28,10 +28,16 @@
 		"optimize-autoloader": true,
 		"classmap-authoritative": true
 	},
+	"autoload": {
+		"psr-4": {
+			"OCA\\Bookmarks\\": "lib/"
+		}
+	},
 	"scripts": {
 		"lint": "find . -name \\*.php -not -path './vendor/*' -print0 | xargs -0 -n1 php -l",
         "cs:check": "php-cs-fixer fix --dry-run --diff",
         "cs:fix": "php-cs-fixer fix",
-		"psalm": "psalm  --output-format=github --no-progress --show-info=true"
+		"psalm": "psalm  --output-format=github --no-progress --no-cache",
+		"psalm-ui": "psalm --no-cache"
 	}
 }
diff --git a/lib/Controller/BookmarkController.php b/lib/Controller/BookmarkController.php
index 8d9c89c0..a1b10ccd 100644
--- a/lib/Controller/BookmarkController.php
+++ b/lib/Controller/BookmarkController.php
@@ -236,7 +236,7 @@ class BookmarkController extends ApiController {
 
 	/**
 	 * @param int $page
-	 * @param null $tags
+	 * @param string[] $tags
 	 * @param string $conjunction
 	 * @param string $sortby
 	 * @param array $search
diff --git a/lib/Db/Bookmark.php b/lib/Db/Bookmark.php
index b34a04e5..f9c78d75 100644
--- a/lib/Db/Bookmark.php
+++ b/lib/Db/Bookmark.php
@@ -13,25 +13,24 @@ use OCP\AppFramework\Db\Entity;
  * Class Bookmark
  *
  * @package OCA\Bookmarks\Db
- * @method getUrl
+ * @method string getUrl()
  * @method setUrl(string $url)
- * @method getTitle
- * @method setTitle(string $title)
- * @method getDescription
+ * @method string getTitle()
+ * @method string getDescription()
  * @method setDescription(string $description)
- * @method getLastmodified
+ * @method int getLastmodified()
  * @method setLastmodified(int $lastmodified)
- * @method getAdded
+ * @method int getAdded()
  * @method setAdded(int $added)
- * @method getClickcount
+ * @method int getClickcount
  * @method setClickcount(int $count)
- * @method getLastPreview
+ * @method int getLastPreview()
  * @method setLastPreview(int $lastpreview)
- * @method getAvailable
+ * @method bool getAvailable()
  * @method setAvailable(boolean $available)
- * @method getArchivedFile
+ * @method int getArchivedFile()
  * @method setArchivedFile(int $fileId)
- * @method getUserId
+ * @method string getUserId()
  * @method setUserId(string $userId)
  */
 class Bookmark extends Entity {
@@ -94,6 +93,6 @@ class Bookmark extends Entity {
 		if (mb_strlen($title) > 255) {
 			$title = mb_substr($title, 0, 254) . '…';
 		}
-		parent::setTitle($title);
+		$this->setter('title', [$title]);
 	}
 }
diff --git a/lib/Db/BookmarkMapper.php b/lib/Db/BookmarkMapper.php
index 7e79d91b..6b8b7f9c 100644
--- a/lib/Db/BookmarkMapper.php
+++ b/lib/Db/BookmarkMapper.php
@@ -197,15 +197,9 @@ class BookmarkMapper extends QBMapper {
 
 		$qb
 			->from('bookmarks', 'b')
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('tr.id', 'b.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'tr.id = b.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
 			->leftJoin('tr', 'bookmarks_shared_folders', 'sf', $qb->expr()->eq('tr.parent_folder', 'sf.folder_id'))
-			->leftJoin('tr', 'bookmarks_tree', 'tr2', $qb->expr()->andX(
-				$qb->expr()->eq('tr2.id', 'tr.parent_folder'),
-				$qb->expr()->eq('tr2.type', $qb->createPositionalParameter(TreeMapper::TYPE_FOLDER))
-			))
+			->leftJoin('tr', 'bookmarks_tree', 'tr2', 'tr2.id = tr.parent_folder AND tr2.type = '. $qb->createPositionalParameter(TreeMapper::TYPE_FOLDER))
 			->leftJoin('tr2', 'bookmarks_shared_folders', 'sf2', $qb->expr()->eq('tr2.parent_folder', 'sf.folder_id'))
 			->where(
 				$qb->expr()->orX(
@@ -394,10 +388,7 @@ class BookmarkMapper extends QBMapper {
 
 		$qb
 			->from('bookmarks', 'b')
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('b.id', 'tr.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'b.id = tr.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
 			->leftJoin('tr', 'bookmarks_shared_folders', 'sf', $qb->expr()->eq('tr.parent_folder', 'sf.folder_id'))
 			->where($qb->expr()->orX(
 				$qb->expr()->eq('b.user_id', $qb->createPositionalParameter($userId)),
@@ -418,10 +409,7 @@ class BookmarkMapper extends QBMapper {
 
 		$qb
 			->from('bookmarks', 'b')
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('b.id', 'tr.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'b.id = tr.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
 			->leftJoin('tr', 'bookmarks_shared_folders', 'sf', $qb->expr()->eq('tr.parent_folder', 'sf.folder_id'))
 			->where($qb->expr()->orX(
 				$qb->expr()->eq('b.user_id', $qb->createPositionalParameter($userId)),
@@ -463,14 +451,8 @@ class BookmarkMapper extends QBMapper {
 
 		$qb
 			->from('bookmarks', 'b')
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('tr.id', 'b.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
-			->leftJoin('tr', 'bookmarks_tree', 'tr2', $qb->expr()->andX(
-				$qb->expr()->eq('tr2.id', 'tr.parent_folder'),
-				$qb->expr()->eq('tr2.type', $qb->createPositionalParameter(TreeMapper::TYPE_FOLDER))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'tr.id = b.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
+			->leftJoin('tr', 'bookmarks_tree', 'tr2', 'tr2.id = tr.parent_folder AND tr2.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_FOLDER))
 			->where(
 				$qb->expr()->orX(
 					$qb->expr()->eq('tr.parent_folder', $qb->createPositionalParameter($publicFolder->getFolderId(), IQueryBuilder::PARAM_INT)),
@@ -635,10 +617,7 @@ class BookmarkMapper extends QBMapper {
 	 * @param IQueryBuilder $qb
 	 */
 	private function _selectFolders(IQueryBuilder $qb): void {
-		$qb->leftJoin('b', 'bookmarks_tree', 'tree', $qb->expr()->andX(
-			$qb->expr()->eq('b.id', 'tree.id'),
-			$qb->expr()->eq('tree.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-		));
+		$qb->leftJoin('b', 'bookmarks_tree', 'tree', 'b.id =tree.id AND tree.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK));
 		if ($this->getDbType() === 'pgsql') {
 			$folders = $qb->createFunction('array_to_string(array_agg(' . $qb->getColumnName('tree.parent_folder') . "), ',')");
 		} else {
diff --git a/lib/Db/Folder.php b/lib/Db/Folder.php
index 25e36b5c..a39055bf 100644
--- a/lib/Db/Folder.php
+++ b/lib/Db/Folder.php
@@ -13,9 +13,9 @@ use OCP\AppFramework\Db\Entity;
  * Class Folder
  *
  * @package OCA\Bookmarks\Db
- * @method getTitle()
+ * @method string getTitle()
  * @method setTitle(string $title)
- * @method getUserId
+ * @method string getUserId()
  * @method setUserId(string $userId)
  */
 class Folder extends Entity {
@@ -27,10 +27,6 @@ class Folder extends Entity {
 	 * @var string
 	 */
 	protected $userId;
-	/**
-	 * @var int
-	 */
-	protected $index;
 
 	public static $columns = ['id', 'title', 'user_id'];
 
diff --git a/lib/Db/PublicFolder.php b/lib/Db/PublicFolder.php
index 27662d61..c7d7f536 100644
--- a/lib/Db/PublicFolder.php
+++ b/lib/Db/PublicFolder.php
@@ -14,14 +14,19 @@ use OCP\AppFramework\Db\Entity;
  *
  * @package OCA\Bookmarks\Db
  *
- * @method getFolderId()
+ * @method string getId()
+ * @method int getFolderId()
  * @method setFolderId(int $folderId)
- * @method getDescription
+ * @method string getDescription()
  * @method setDescription(string $description)
- * @method getCreatedAt
+ * @method int getCreatedAt()
  * @method setCreatedAt(int $createdAt)
  */
 class PublicFolder extends Entity {
+	/**
+	 * @var string
+	 */
+	public $id;
 	protected $folderId;
 	protected $description;
 	protected $createdAt;
diff --git a/lib/Db/Share.php b/lib/Db/Share.php
index f889b56a..522bd0f1 100644
--- a/lib/Db/Share.php
+++ b/lib/Db/Share.php
@@ -14,19 +14,19 @@ use OCP\AppFramework\Db\Entity;
  *
  * @package OCA\Bookmarks\Db
  *
- * @method getFolderId
+ * @method int getFolderId()
  * @method setFolderId(int $folderId)
- * @method getOwner
+ * @method string getOwner()
  * @method setOwner(string $owner)
- * @method getParticipant
+ * @method string getParticipant
  * @method setParticipant(string $participant)
- * @method getType
+ * @method string getType()
  * @method setType(string $type)
- * @method getCanWrite
+ * @method bool getCanWrite()
  * @method setCanWrite(bool $canWrite)
- * @method getCanShare
+ * @method bool getCanShare()
  * @method setCanShare(bool $canShare)
- * @method getCreatedAt
+ * @method int getCreatedAt()
  * @method setCreatedAt(int $createdAt)
  */
 class Share extends Entity {
diff --git a/lib/Db/SharedFolder.php b/lib/Db/SharedFolder.php
index 32c41e74..18519486 100644
--- a/lib/Db/SharedFolder.php
+++ b/lib/Db/SharedFolder.php
@@ -14,12 +14,12 @@ use OCP\AppFramework\Db\Entity;
  *
  * @package OCA\Bookmarks\Db
  *
- * @method getShareId
+ * @method int getShareId()
  * @method setFolderId(int $shareId)
- * @method getFolderId()
- * @method getUserId
+ * @method int getFolderId()
+ * @method string getUserId()
  * @method setUserId(string $userId)
- * @method getTitle
+ * @method string getTitle()
  * @method setTitle(string $title)
  */
 class SharedFolder extends Entity {
diff --git a/lib/Db/TagMapper.php b/lib/Db/TagMapper.php
index 3c0ca6f1..cbb40d06 100644
--- a/lib/Db/TagMapper.php
+++ b/lib/Db/TagMapper.php
@@ -44,10 +44,7 @@ class TagMapper {
 			->selectAlias($qb->createFunction('COUNT(DISTINCT ' . $qb->getColumnName('t.bookmark_id') . ')'), 'count')
 			->from('bookmarks_tags', 't')
 			->innerJoin('t', 'bookmarks', 'b', $qb->expr()->eq('b.id', 't.bookmark_id'))
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('b.id', 'tr.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'b.id = tr.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
 			->leftJoin('tr', 'bookmarks_shared_folders', 'sf', $qb->expr()->eq('tr.parent_folder', 'sf.folder_id'))
 			->where($qb->expr()->eq('b.user_id', $qb->createPositionalParameter($userId)))
 			->orWhere($qb->expr()->andX(
@@ -70,10 +67,7 @@ class TagMapper {
 			->select('t.tag')
 			->from('bookmarks_tags', 't')
 			->innerJoin('t', 'bookmarks', 'b', $qb->expr()->eq('b.id', 't.bookmark_id'))
-			->leftJoin('b', 'bookmarks_tree', 'tr', $qb->expr()->andX(
-				$qb->expr()->eq('b.id', 'tr.id'),
-				$qb->expr()->eq('tr.type', $qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
-			))
+			->leftJoin('b', 'bookmarks_tree', 'tr', 'b.id = tr.id AND tr.type = '.$qb->createPositionalParameter(TreeMapper::TYPE_BOOKMARK))
 			->leftJoin('tr', 'bookmarks_shared_folders', 'sf', $qb->expr()->eq('tr.parent_folder', 'sf.folder_id'))
 			->where($qb->expr()->eq('b.user_id', $qb->createPositionalParameter($userId)))
 			->orWhere($qb->expr()->andX(
diff --git a/lib/Db/TreeMapper.php b/lib/Db/TreeMapper.php
index 6163114a..d0f6028d 100644
--- a/lib/Db/TreeMapper.php
+++ b/lib/Db/TreeMapper.php
@@ -388,10 +388,7 @@ class TreeMapper extends QBMapper {
 			$qb = $this->db->getQueryBuilder();
 			$qb->select('b.id')
 				->from('bookmarks', 'b')
-				->leftJoin('b', 'bookmarks_tree', 't',  $qb->expr()->andX(
-					$qb->expr()->eq('b.id', 't.id'),
-					$qb->expr()->eq('t.type', $qb->createPositionalParameter(self::TYPE_BOOKMARK))
-				))
+				->leftJoin('b', 'bookmarks_tree', 't', 'b.id = t.id AND t.type = '.$qb->createPositionalParameter(self::TYPE_BOOKMARK))
 				->where($qb->expr()->isNull('t.id'));
 			$orphanedBookmarks = $qb->execute();
 			while ($bookmark = $orphanedBookmarks->fetchColumn()) {
diff --git a/lib/Migration/DeduplicateSharedFoldersRepairStep.php b/lib/Migration/DeduplicateSharedFoldersRepairStep.php
index 3be94868..f201e08b 100644
--- a/lib/Migration/DeduplicateSharedFoldersRepairStep.php
+++ b/lib/Migration/DeduplicateSharedFoldersRepairStep.php
@@ -39,10 +39,7 @@ class DeduplicateSharedFoldersRepairStep implements IRepairStep {
 		$qb = $this->db->getQueryBuilder();
 		$qb->select('p1.id')
 			->from('bookmarks_shared_folders', 'p1')
-			->leftJoin('p1', 'bookmarks_shared_folders', 'p2', $qb->expr()->andX(
-				$qb->expr()->eq('p1.folder_id', 'p2.folder_id'),
-				$qb->expr()->eq('p1.user_id', 'p2.user_id')
-			))
+			->leftJoin('p1', 'bookmarks_shared_folders', 'p2', 'p1.folder_id = p2.folder_id AND p1.user_id = p2.user_id')
 			->where($qb->expr()->lt('p2.id', 'p1.id'));
 		$duplicateSharedFolders = $qb->execute();
 		$i = 0;
diff --git a/lib/Migration/Version000014000Date20181029094721.php b/lib/Migration/Version000014000Date20181029094721.php
index 6d5e41d0..02e0a862 100644
--- a/lib/Migration/Version000014000Date20181029094721.php
+++ b/lib/Migration/Version000014000Date20181029094721.php
@@ -102,7 +102,7 @@ class Version000014000Date20181029094721 extends SimpleMigrationStep {
 					$qb = $this->db->getQueryBuilder();
 					$qb
 						->update('bookmarks_folders_bookmarks')
-						->set(['index' => $qb->createPositionalParameter($i)])
+						->set('index', $qb->createPositionalParameter($i))
 						->where($qb->expr()->eq('bookmark_id', $qb->createPositionalParameter($child['id'])))
 						->andWhere($qb->expr()->eq('folder_id', $qb->createPositionalParameter($folder)));
 					$qb->execute();
@@ -110,7 +110,7 @@ class Version000014000Date20181029094721 extends SimpleMigrationStep {
 					$qb = $this->db->getQueryBuilder();
 					$qb
 						->update('bookmarks_folders')
-						->set(['index' => $qb->createPositionalParameter($i)])
+						->set('index', $qb->createPositionalParameter($i))
 						->where($qb->expr()->eq('id', $qb->createPositionalParameter($child['id'])))
 						->andWhere($qb->expr()->eq('parent_folder', $qb->createPositionalParameter($folder)));
 					$qb->execute();
diff --git a/lib/QueryParameters.php b/lib/QueryParameters.php
index 4b05a2ba..b8edf76f 100644
--- a/lib/QueryParameters.php
+++ b/lib/QueryParameters.php
@@ -97,13 +97,13 @@ class QueryParameters {
 	/**
 	 * @param string|null $default
 	 * @param array|null $columns
-	 * @return string
+	 * @return string|null
 	 */
-	public function getSortBy(string $default = null, array $columns = null): string {
+	public function getSortBy(string $default = null, array $columns = null): ?string {
 		if (isset($default) && !isset($this->sortBy)) {
 			return $default;
 		}
-		if (isset($columns) && !in_array($this->sortBy, $columns, true)) {
+		if (isset($default, $columns) && !in_array($this->sortBy, $columns, true)) {
 			return $default;
 		}
 		return $this->sortBy;
diff --git a/lib/Service/BookmarksParser.php b/lib/Service/BookmarksParser.php
index 3bfc67f7..60f85370 100644
--- a/lib/Service/BookmarksParser.php
+++ b/lib/Service/BookmarksParser.php
@@ -249,13 +249,15 @@ class BookmarksParser {
 	 */
 	private function getAttributes(DOMNode $node): array {
 		$attributes = [];
-		$length = $node->attributes->length;
-		for ($i = 0; $i < $length; ++$i) {
-			$item = $node->attributes->item($i);
-			if ($item === null) {
-				continue;
+		if ($node->attributes) {
+			$length = $node->attributes->length;
+			for ($i = 0; $i < $length; ++$i) {
+				$item = $node->attributes->item($i);
+				if ($item === null) {
+					continue;
+				}
+				$attributes[strtolower($item->nodeName)] = $item->nodeValue;
 			}
-			$attributes[strtolower($item->nodeName)] = $item->nodeValue;
 		}
 		$lastModified = null;
 		if (isset($attributes['time_added'])) {
diff --git a/lib/Service/FileCache.php b/lib/Service/FileCache.php
index c61462b6..1c8fb1b6 100644
--- a/lib/Service/FileCache.php
+++ b/lib/Service/FileCache.php
@@ -59,7 +59,7 @@ class FileCache implements ICache {
 	 * @param string $key
 	 * @param mixed $value
 	 * @param int $ttl
-	 * @return bool|mixed
+	 * @return bool
 	 * @throws NotFoundException
 	 * @throws NotPermittedException
 	 */
@@ -82,12 +82,12 @@ class FileCache implements ICache {
 
 	/**
 	 * @param string $key
-	 * @return bool|mixed
+	 * @return bool
 	 * @throws NotFoundException
 	 * @throws NotPermittedException
 	 */
 	public function remove($key) {
-		return $this->storage->getFile($key)->delete();
+		return (boolean) $this->storage->getFile($key)->delete();
 	}
 
 	/**
diff --git a/lib/Service/FolderService.php b/lib/Service/FolderService.php
index 18742c83..b69e4853 100644
--- a/lib/Service/FolderService.php
+++ b/lib/Service/FolderService.php
@@ -210,10 +210,10 @@ class FolderService {
 	}
 
 	/**
-	 * @param $userId
-	 * @param $folderId
-	 * @param null $title
-	 * @param null $parent_folder
+	 * @param string $userId
+	 * @param int $folderId
+	 * @param string $title
+	 * @param int $parent_folder
 	 * @return Folder|SharedFolder
 	 * @throws DoesNotExistException
 	 * @throws MultipleObjectsReturnedException
@@ -271,6 +271,7 @@ class FolderService {
 	public function createFolderPublicToken($folderId): string {
 		$this->folderMapper->find($folderId);
 		try {
+			/** @var PublicFolder $publicFolder */
 			$publicFolder = $this->publicFolderMapper->findByFolder($folderId);
 		} catch (DoesNotExistException $e) {
 			$publicFolder = new PublicFolder();
@@ -370,7 +371,7 @@ class FolderService {
 	/**
 	 * @param string $userId
 	 * @param $file
-	 * @param null $folder
+	 * @param int $folder
 	 * @return array
 	 * @throws DoesNotExistException
 	 * @throws MultipleObjectsReturnedException
diff --git a/lib/Service/HtmlImporter.php b/lib/Service/HtmlImporter.php
index 1b0fba2b..842b5278 100644
--- a/lib/Service/HtmlImporter.php
+++ b/lib/Service/HtmlImporter.php
@@ -197,7 +197,7 @@ class HtmlImporter {
 	 * @param string $userId
 	 * @param int $folderId
 	 * @param array $bookmark
-	 * @param null $index
+	 * @param null|int $index
 	 * @return Bookmark|Entity
 	 * @throws UrlParseError
 	 * @throws AlreadyExistsError
diff --git a/lib/Service/Previewers/PageresBookmarkPreviewer.php b/lib/Service/Previewers/PageresBookmarkPreviewer.php
index c2aaefab..1ca37ee3 100644
--- a/lib/Service/Previewers/PageresBookmarkPreviewer.php
+++ b/lib/Service/Previewers/PageresBookmarkPreviewer.php
@@ -33,7 +33,7 @@ class PageresBookmarkPreviewer implements IBookmarkPreviewer {
 	}
 
 	/**
-	 * @param Bookmark $bookmark
+	 * @param Bookmark|null $bookmark
 	 *
 	 * @return Image|null
 	 */
diff --git a/lib/Service/Previewers/ScreeenlyBookmarkPreviewer.php b/lib/Service/Previewers/ScreeenlyBookmarkPreviewer.php
index 2d09c314..84d25127 100644
--- a/lib/Service/Previewers/ScreeenlyBookmarkPreviewer.php
+++ b/lib/Service/Previewers/ScreeenlyBookmarkPreviewer.php
@@ -12,7 +12,7 @@ use OCA\Bookmarks\Contract\IBookmarkPreviewer;
 use OCA\Bookmarks\Contract\IImage;
 use OCA\Bookmarks\Db\Bookmark;
 use OCA\Bookmarks\Image;
-use OCA\Bookmarks\Service\FileCache;
+use OCP\Http\Client\IClient;
 use OCP\Http\Client\IClientService;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
@@ -22,28 +22,36 @@ class ScreeenlyBookmarkPreviewer implements IBookmarkPreviewer {
 
 	public const HTTP_TIMEOUT = 10 * 1000;
 
+	/**
+	 * @var string
+	 */
 	private $apiKey;
 
+	/**
+	 * @var IClient
+	 */
 	private $client;
 
-	/** @var IConfig */
-	private $config;
-
-	private $cache;
 
 	/** @var LoggerInterface */
 	private $logger;
 
+	/**
+	 * @var int
+	 */
 	private $width = 800;
 
+	/**
+	 * @var int
+	 */
 	private $height = 800;
+
 	/**
 	 * @var string
 	 */
 	private $apiUrl;
 
-	public function __construct(FileCache $cache, IConfig $config, IClientService $clientService, LoggerInterface $logger) {
-		$this->config = $config;
+	public function __construct(IConfig $config, IClientService $clientService, LoggerInterface $logger) {
 		$this->apiUrl = $config->getAppValue('bookmarks', 'previews.screenly.url', 'http://screeenly.com/api/v1/fullsize');
 		$this->apiKey = $config->getAppValue('bookmarks', 'previews.screenly.token', '');
 		$this->client = $clientService->newClient();
@@ -51,7 +59,7 @@ class ScreeenlyBookmarkPreviewer implements IBookmarkPreviewer {
 	}
 
 	/**
-	 * @param Bookmark $bookmark
+	 * @param Bookmark|null $bookmark
 	 *
 	 * @return Image|null
 	 */
@@ -69,7 +77,7 @@ class ScreeenlyBookmarkPreviewer implements IBookmarkPreviewer {
 	}
 
 	/**
-	 * @param $url
+	 * @param string $url
 	 * @return Image|null
 	 */
 	public function fetchImage($url): ?Image {
diff --git a/lib/Service/Previewers/ScreenshotMachineBookmarkPreviewer.php b/lib/Service/Previewers/ScreenshotMachineBookmarkPreviewer.php
index fe158681..8cf417a9 100644
--- a/lib/Service/Previewers/ScreenshotMachineBookmarkPreviewer.php
+++ b/lib/Service/Previewers/ScreenshotMachineBookmarkPreviewer.php
@@ -12,7 +12,7 @@ use OCA\Bookmarks\Contract\IBookmarkPreviewer;
 use OCA\Bookmarks\Contract\IImage;
 use OCA\Bookmarks\Db\Bookmark;
 use OCA\Bookmarks\Image;
-use OCA\Bookmarks\Service\FileCache;
+use OCP\Http\Client\IClient;
 use OCP\Http\Client\IClientService;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
@@ -22,34 +22,38 @@ class ScreenshotMachineBookmarkPreviewer implements IBookmarkPreviewer {
 
 	public const HTTP_TIMEOUT = 10 * 1000;
 
+	/**
+	 * @var string
+	 */
 	private $apiKey;
 
+	/**
+	 * @var IClient
+	 */
 	private $client;
 
-	/** @var IConfig */
-	private $config;
-
 	/** @var LoggerInterface */
 	private $logger;
 
+	/**
+	 * @var int
+	 */
 	private $width = 800;
 
-	private $height = 800;
 	/**
-	 * @var FileCache
+	 * @var int
 	 */
-	private $cache;
+	private $height = 800;
 
-	public function __construct(FileCache $cache, IConfig $config, IClientService $clientService, LoggerInterface $logger) {
-		$this->config = $config;
+
+	public function __construct(IConfig $config, IClientService $clientService, LoggerInterface $logger) {
 		$this->apiKey = $config->getAppValue('bookmarks', 'previews.screenshotmachine.key', '');
-		$this->cache = $cache;
 		$this->client = $clientService->newClient();
 		$this->logger = $logger;
 	}
 
 	/**
-	 * @param Bookmark $bookmark
+	 * @param Bookmark|null $bookmark
 	 *
 	 * @return Image|null
 	 */
diff --git a/lib/Service/Previewers/WebshotBookmarkPreviewer.php b/lib/Service/Previewers/WebshotBookmarkPreviewer.php
index 6b49299b..9e2a96e0 100644
--- a/lib/Service/Previewers/WebshotBookmarkPreviewer.php
+++ b/lib/Service/Previewers/WebshotBookmarkPreviewer.php
@@ -13,6 +13,7 @@ use OCA\Bookmarks\Contract\IImage;
 use OCA\Bookmarks\Db\Bookmark;
 use OCA\Bookmarks\Image;
 use OCA\Bookmarks\Service\FileCache;
+use OCP\Http\Client\IClient;
 use OCP\Http\Client\IClientService;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
@@ -22,18 +23,30 @@ class WebshotBookmarkPreviewer implements IBookmarkPreviewer {
 
 	public const HTTP_TIMEOUT = 10 * 1000;
 
+	/**
+	 * @var IClient
+	 */
 	private $client;
 
 	/** @var IConfig */
 	private $config;
 
+	/**
+	 * @var FileCache
+	 */
 	private $cache;
 
 	/** @var LoggerInterface */
 	private $logger;
 
+	/**
+	 * @var int
+	 */
 	private $width = 800;
 
+	/**
+	 * @var int
+	 */
 	private $height = 800;
 	/**
 	 * @var string
diff --git a/lib/Service/UrlNormalizer.php b/lib/Service/UrlNormalizer.php
index f61f7533..d1b7ce33 100644
--- a/lib/Service/UrlNormalizer.php
+++ b/lib/Service/UrlNormalizer.php
@@ -12,6 +12,7 @@ use Rowbot\URL\Exception\TypeError;
 use Rowbot\URL\URL;
 
 class UrlNormalizer {
+	/** @var array<string, string>  */
 	private $cache = [];
 
 	public function __construct() {
diff --git a/psalm.xml b/psalm.xml
index cd4d6623..bc2225b9 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -5,7 +5,7 @@
   ~ This file is licensed under the Affero General Public License version 3 or later. See the COPYING file.
   -->
 <psalm
-    errorLevel="1"
+    errorLevel="5"
     resolveFromConfigFile="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
@@ -21,6 +21,24 @@
         <directory name="vendor" />
         <ignoreFiles>
             <directory name="vendor/phpunit/php-code-coverage" />
+            <directory name="vendor/vimeo" />
         </ignoreFiles>
     </extraFiles>
+    <issueHandlers>
+        <UndefinedClass>
+            <errorLevel type="suppress">
+                <referencedClass name="OC" />
+                <referencedClass name="Doctrine\DBAL\Types\Type" />
+            </errorLevel>
+        </UndefinedClass>
+        <UndefinedDocblockClass>
+            <errorLevel type="suppress">
+                <referencedClass name="Doctrine\DBAL\Schema\Schema" />
+                <referencedClass name="Doctrine\DBAL\Schema\SchemaException" />
+                <referencedClass name="Doctrine\DBAL\Driver\Statement" />
+                <referencedClass name="Doctrine\DBAL\Schema\Table" />
+                <referencedClass name="Doctrine\DBAL\Types\Type" />
+            </errorLevel>
+        </UndefinedDocblockClass>
+    </issueHandlers>
 </psalm>