diff --git a/.php-cs-fixer.php b/.php-cs-fixer.php
index 3ca302e7..9bd25016 100644
--- a/.php-cs-fixer.php
+++ b/.php-cs-fixer.php
@@ -34,6 +34,7 @@ $config
         '@PhpCsFixer:risky' => true,
         'general_phpdoc_annotation_remove' => ['annotations' => ['expectedDeprecation']], // one should use PHPUnit built-in method instead
         'modernize_strpos' => false, // needs PHP 8+ or polyfill
+        'phpdoc_to_comment' => ['ignored_tags' => ['psalm-suppress', 'template-implements']],
     ])
     ->setFinder($finder)
 ;
diff --git a/Makefile b/Makefile
index 6038e93e..465536e0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,17 +1,20 @@
 all: dev-setup lint build-js-production test
 
 # Dev env management
-dev-setup: clean clean-dev npm-init exiftool php-cs-fixer
+dev-setup: clean clean-dev npm-init exiftool install-tools
 
 exiftool:
 	sh scripts/get-exiftool.sh
 
-php-cs-fixer:
-	mkdir -p tools/php-cs-fixer
-	composer require --dev --working-dir=tools/php-cs-fixer friendsofphp/php-cs-fixer
+install-tools:
+	mkdir -p tools
+	composer require --dev --working-dir=tools friendsofphp/php-cs-fixer vimeo/psalm
 
 php-lint:
-	tools/php-cs-fixer/vendor/bin/php-cs-fixer fix lib
+	tools/vendor/bin/php-cs-fixer fix lib
+
+psalm:
+	tools/vendor/bin/psalm
 
 npm-init:
 	npm ci
@@ -19,7 +22,7 @@ npm-init:
 npm-update:
 	npm update
 
-.PHONY: dev-setup exiftool php-cs-fixer php-lint npm-init npm-update
+.PHONY: dev-setup exiftool install-tools php-lint psalm npm-init npm-update
 
 # Building
 build-js:
diff --git a/composer.json b/composer.json
index f57885d0..a9e85a31 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
-    "name": "Memories",
-    "description": "p",
+    "name": "radialapps/memories",
+    "description": "Fast and advanced photo management for Nextcloud",
     "type": "project",
     "license": "AGPL",
     "authors": [
@@ -9,7 +9,5 @@
         }
     ],
     "require": {},
-    "require-dev": {
-        "phpunit/phpunit": "^5.4"
-    }
+    "require-dev": {}
 }
diff --git a/lib/ClustersBackend/AlbumsBackend.php b/lib/ClustersBackend/AlbumsBackend.php
index f12f0366..c0b6b4cd 100644
--- a/lib/ClustersBackend/AlbumsBackend.php
+++ b/lib/ClustersBackend/AlbumsBackend.php
@@ -60,7 +60,7 @@ class AlbumsBackend extends Backend
         return Util::albumsIsEnabled();
     }
 
-    public function clusterName(string $name)
+    public function clusterName(string $name): string
     {
         return explode('/', $name)[1];
     }
@@ -138,7 +138,7 @@ class AlbumsBackend extends Backend
         return $this->albumsQuery->getAlbumPhotos($id, $limit) ?? [];
     }
 
-    public function sortPhotosForPreview(array &$photos)
+    public function sortPhotosForPreview(array &$photos): void
     {
         // Do nothing, the photos are already sorted by added date desc
     }
diff --git a/lib/ClustersBackend/Backend.php b/lib/ClustersBackend/Backend.php
index 3e28b7cd..e697bf9a 100644
--- a/lib/ClustersBackend/Backend.php
+++ b/lib/ClustersBackend/Backend.php
@@ -83,7 +83,7 @@ abstract class Backend
     /**
      * Human readable name for the cluster.
      */
-    public function clusterName(string $name)
+    public function clusterName(string $name): string
     {
         return $name;
     }
@@ -92,7 +92,7 @@ abstract class Backend
      * Put the photo objects in priority list.
      * Works on the array in place.
      */
-    public function sortPhotosForPreview(array &$photos)
+    public function sortPhotosForPreview(array &$photos): void
     {
         shuffle($photos);
     }
diff --git a/lib/ClustersBackend/FaceRecognitionBackend.php b/lib/ClustersBackend/FaceRecognitionBackend.php
index b593d3aa..31937894 100644
--- a/lib/ClustersBackend/FaceRecognitionBackend.php
+++ b/lib/ClustersBackend/FaceRecognitionBackend.php
@@ -191,7 +191,7 @@ class FaceRecognitionBackend extends Backend
         return $this->tq->executeQueryWithCTEs($query)->fetchAll() ?: [];
     }
 
-    public function sortPhotosForPreview(array &$photos)
+    public function sortPhotosForPreview(array &$photos): void
     {
         // Convert to recognize format (percentage position-size)
         foreach ($photos as &$p) {
@@ -216,15 +216,15 @@ class FaceRecognitionBackend extends Backend
 
     private function model(): int
     {
-        return (int) $this->config->getAppValue('facerecognition', 'model', -1);
+        return (int) $this->config->getAppValue('facerecognition', 'model', (string) -1);
     }
 
     private function minFaceInClusters(): int
     {
-        return (int) $this->config->getAppValue('facerecognition', 'min_faces_in_cluster', 5);
+        return (int) $this->config->getAppValue('facerecognition', 'min_faces_in_cluster', (string) 5);
     }
 
-    private function getFaceRecognitionClusters(int $fileid = 0)
+    private function getFaceRecognitionClusters(int $fileid = 0): array
     {
         $query = $this->tq->getBuilder();
 
@@ -276,7 +276,7 @@ class FaceRecognitionBackend extends Backend
         return $this->tq->executeQueryWithCTEs($query)->fetchAll() ?: [];
     }
 
-    private function getFaceRecognitionPersons(int $fileid = 0)
+    private function getFaceRecognitionPersons(int $fileid = 0): array
     {
         $query = $this->tq->getBuilder();
 
diff --git a/lib/ClustersBackend/PeopleBackendUtils.php b/lib/ClustersBackend/PeopleBackendUtils.php
index d0637797..40c832c8 100644
--- a/lib/ClustersBackend/PeopleBackendUtils.php
+++ b/lib/ClustersBackend/PeopleBackendUtils.php
@@ -87,11 +87,13 @@ trait PeopleBackendUtils
      * @param array                           $photo   The face object
      * @param float                           $padding The padding to add around the face
      *
-     * @return [Blob, mimetype] of resulting image
+     * @return string[] [Blob, mimetype] of resulting image
      *
      * @throws \Exception if file could not be used
+     *
+     * @psalm-return list{string, string}
      */
-    private function cropFace($file, array $photo, float $padding)
+    private function cropFace($file, array $photo, float $padding): array
     {
         $img = new \OCP\Image();
         $img->loadFromData($file->getContent());
@@ -121,6 +123,13 @@ trait PeopleBackendUtils
         // Max 512x512
         $img->scaleDownToFit(512, 512);
 
-        return [$img->data(), $img->mimeType()];
+        // Get blob and mimetype
+        $data = $img->data();
+        $mime = $img->mimeType();
+        if (null === $data || null === $mime) {
+            throw new \Exception('Could not get image data');
+        }
+
+        return [$data, $mime];
     }
 }
diff --git a/lib/ClustersBackend/RecognizeBackend.php b/lib/ClustersBackend/RecognizeBackend.php
index a36607a7..fcb56c7b 100644
--- a/lib/ClustersBackend/RecognizeBackend.php
+++ b/lib/ClustersBackend/RecognizeBackend.php
@@ -231,7 +231,7 @@ class RecognizeBackend extends Backend
         return $this->tq->executeQueryWithCTEs($query)->fetchAll() ?: [];
     }
 
-    public function sortPhotosForPreview(array &$photos)
+    public function sortPhotosForPreview(array &$photos): void
     {
         $this->sortByScores($photos);
     }
diff --git a/lib/Command/Index.php b/lib/Command/Index.php
index eb998791..301a066d 100644
--- a/lib/Command/Index.php
+++ b/lib/Command/Index.php
@@ -203,7 +203,7 @@ class Index extends Command
      *
      * @param mixed $closure
      */
-    private function runForUsers($closure)
+    private function runForUsers($closure): void
     {
         if ($uid = $this->opts->user) {
             if ($user = $this->userManager->get($uid)) {
diff --git a/lib/Command/MigrateGoogleTakeout.php b/lib/Command/MigrateGoogleTakeout.php
index c284d063..0c59d25a 100644
--- a/lib/Command/MigrateGoogleTakeout.php
+++ b/lib/Command/MigrateGoogleTakeout.php
@@ -296,7 +296,12 @@ class MigrateGoogleTakeout extends Command
         ++$this->nProcessed;
     }
 
-    protected function takeoutToExiftoolJson(array $json)
+    /**
+     * @return (float|mixed|string)[]
+     *
+     * @psalm-return array<string, float|mixed|string>
+     */
+    protected function takeoutToExiftoolJson(array $json): array
     {
         // Helper to get a value from nested JSON
         $get = static function (string $source) use ($json) {
diff --git a/lib/Controller/AdminController.php b/lib/Controller/AdminController.php
index a767853c..f2794153 100644
--- a/lib/Controller/AdminController.php
+++ b/lib/Controller/AdminController.php
@@ -109,9 +109,9 @@ class AdminController extends GenericApiController
             $status['indexed_count'] = $index->getIndexedCount();
 
             // Automatic indexing stats
-            $jobStart = $config->getAppValue(Application::APPNAME, 'last_index_job_start', 0);
+            $jobStart = (int) $config->getAppValue(Application::APPNAME, 'last_index_job_start', (string) 0);
             $status['last_index_job_start'] = $jobStart ? time() - $jobStart : 0; // Seconds ago
-            $status['last_index_job_duration'] = $config->getAppValue(Application::APPNAME, 'last_index_job_duration', 0);
+            $status['last_index_job_duration'] = (float) $config->getAppValue(Application::APPNAME, 'last_index_job_duration', (string) 0);
             $status['last_index_job_status'] = $config->getAppValue(Application::APPNAME, 'last_index_job_status', 'Indexing has not been run yet');
             $status['last_index_job_status_type'] = $config->getAppValue(Application::APPNAME, 'last_index_job_status_type', 'warning');
 
diff --git a/lib/Controller/DaysController.php b/lib/Controller/DaysController.php
index ff81abdb..ef17ff51 100644
--- a/lib/Controller/DaysController.php
+++ b/lib/Controller/DaysController.php
@@ -134,7 +134,7 @@ class DaysController extends GenericApiController
     /**
      * Get transformations depending on the request.
      */
-    private function getTransformations()
+    private function getTransformations(): array
     {
         $transforms = [];
 
@@ -180,7 +180,7 @@ class DaysController extends GenericApiController
      *
      * @param array $days the days array
      */
-    private function preloadDays(array &$days)
+    private function preloadDays(array &$days): void
     {
         // Do not preload anything for native clients.
         // Since the contents of preloads are trusted, clients will not load locals.
@@ -234,7 +234,7 @@ class DaysController extends GenericApiController
      * Convert days response to months response.
      * The dayId is used to group the days into months.
      */
-    private function daysToMonths(array $days)
+    private function daysToMonths(array $days): array
     {
         $months = [];
         foreach ($days as $day) {
@@ -255,45 +255,49 @@ class DaysController extends GenericApiController
         return $months;
     }
 
-    /** Convert list of month IDs to list of dayIds */
-    private function monthIdToDayIds(int $monthId)
+    /**
+     * Convert list of month IDs to list of dayIds.
+     *
+     * @return int[] The list of dayIds
+     */
+    private function monthIdToDayIds(int $monthId): array
     {
         $dayIds = [];
         $firstDay = (int) $monthId;
         $lastDay = strtotime(date('Ymt', $firstDay * 86400)) / 86400;
         for ($i = $firstDay; $i <= $lastDay; ++$i) {
-            $dayIds[] = (string) $i;
+            $dayIds[] = $i;
         }
 
         return $dayIds;
     }
 
-    private function isRecursive()
+    private function isRecursive(): bool
     {
         return null === $this->request->getParam('folder') || $this->request->getParam('recursive');
     }
 
-    private function isArchive()
+    private function isArchive(): bool
     {
         return null !== $this->request->getParam('archive');
     }
 
-    private function isHidden()
+    private function isHidden(): bool
     {
         return null !== $this->request->getParam('hidden');
     }
 
-    private function noPreload()
+    private function noPreload(): bool
     {
         return null !== $this->request->getParam('nopreload');
     }
 
-    private function isMonthView()
+    private function isMonthView(): bool
     {
         return null !== $this->request->getParam('monthView');
     }
 
-    private function isReverse()
+    private function isReverse(): bool
     {
         return null !== $this->request->getParam('reverse');
     }
diff --git a/lib/Controller/DownloadController.php b/lib/Controller/DownloadController.php
index e48ad1ce..6141a9d3 100644
--- a/lib/Controller/DownloadController.php
+++ b/lib/Controller/DownloadController.php
@@ -282,7 +282,7 @@ class DownloadController extends GenericApiController
                 /** @var bool|resource */
                 $handle = false;
 
-                /** @var ?File */
+                /** @var ?\OCP\Files\File */
                 $file = null;
 
                 /** @var ?string */
diff --git a/lib/Controller/ImageController.php b/lib/Controller/ImageController.php
index abe91374..43b7c824 100644
--- a/lib/Controller/ImageController.php
+++ b/lib/Controller/ImageController.php
@@ -50,7 +50,7 @@ class ImageController extends GenericApiController
         int $y = 32,
         bool $a = false,
         string $mode = 'fill'
-    ) {
+    ): Http\Response {
         return Util::guardEx(function () use ($id, $x, $y, $a, $mode) {
             if (-1 === $id || 0 === $x || 0 === $y) {
                 throw Exceptions::MissingParameter('id, x, y');
diff --git a/lib/Controller/OtherController.php b/lib/Controller/OtherController.php
index 3f5328f5..db117580 100644
--- a/lib/Controller/OtherController.php
+++ b/lib/Controller/OtherController.php
@@ -77,7 +77,7 @@ class OtherController extends GenericApiController
             }
 
             // helper function to get user config values
-            $getAppConfig = function ($key, $default) use ($uid) {
+            $getAppConfig = function ($key, $default) use ($uid): string {
                 return $this->config->getUserValue($uid, Application::APPNAME, $key, $default);
             };
 
diff --git a/lib/Controller/PageController.php b/lib/Controller/PageController.php
index 78dd5372..5a9509ae 100644
--- a/lib/Controller/PageController.php
+++ b/lib/Controller/PageController.php
@@ -69,7 +69,7 @@ class PageController extends Controller
     {
         // Image domains MUST be added to the connect domain list
         // because of the service worker fetch() call
-        $addImageDomain = static function ($url) use (&$policy) {
+        $addImageDomain = static function ($url) use (&$policy): void {
             $policy->addAllowedImageDomain($url);
             $policy->addAllowedConnectDomain($url);
         };
@@ -108,7 +108,7 @@ class PageController extends Controller
     /**
      * Get params for main.php template.
      */
-    public static function getMainParams()
+    public static function getMainParams(): array
     {
         return [
             'native' => Util::callerIsNative(),
diff --git a/lib/Controller/PublicAlbumController.php b/lib/Controller/PublicAlbumController.php
index 10dfeb1a..b33b6674 100644
--- a/lib/Controller/PublicAlbumController.php
+++ b/lib/Controller/PublicAlbumController.php
@@ -139,7 +139,7 @@ class PublicAlbumController extends Controller
         return $downloadController->file($handle);
     }
 
-    private function addOgMetadata(array $album, string $token)
+    private function addOgMetadata(array $album, string $token): void
     {
         $fileId = (int) $album['last_added_photo'];
         $albumId = (int) $album['album_id'];
diff --git a/lib/Controller/ShareController.php b/lib/Controller/ShareController.php
index ed118e53..60292c28 100644
--- a/lib/Controller/ShareController.php
+++ b/lib/Controller/ShareController.php
@@ -111,7 +111,7 @@ class ShareController extends GenericApiController
         });
     }
 
-    private function getNodeByIdOrPath($id, $path)
+    private function getNodeByIdOrPath($id, $path): \OCP\Files\Node
     {
         $uid = Util::getUID();
 
@@ -133,7 +133,7 @@ class ShareController extends GenericApiController
         return $file;
     }
 
-    private function makeShareResponse(\OCP\Share\IShare $share)
+    private function makeShareResponse(\OCP\Share\IShare $share): array
     {
         /** @var \OCP\IURLGenerator $urlGenerator */
         $urlGenerator = \OC::$server->get(\OCP\IURLGenerator::class);
diff --git a/lib/Controller/VideoController.php b/lib/Controller/VideoController.php
index 41d78bfb..13ea0a94 100644
--- a/lib/Controller/VideoController.php
+++ b/lib/Controller/VideoController.php
@@ -118,7 +118,7 @@ class VideoController extends GenericApiController
         string $liveid = '',
         string $format = '',
         string $transcode = ''
-    ) {
+    ): Http\Response {
         return Util::guardEx(function () use ($fileid, $liveid, $format, $transcode) {
             $file = $this->fs->getUserFile($fileid);
 
@@ -230,7 +230,7 @@ class VideoController extends GenericApiController
         });
     }
 
-    private function getUpstream(string $client, string $path, string $profile)
+    private function getUpstream(string $client, string $path, string $profile): int
     {
         $returnCode = $this->getUpstreamInternal($client, $path, $profile);
 
@@ -251,7 +251,7 @@ class VideoController extends GenericApiController
         return $returnCode;
     }
 
-    private function getUpstreamInternal(string $client, string $path, string $profile)
+    private function getUpstreamInternal(string $client, string $path, string $profile): int
     {
         // Make sure query params are repeated
         // For example, in folder sharing, we need the params on every request
diff --git a/lib/Cron/IndexJob.php b/lib/Cron/IndexJob.php
index f0ccda79..9ea4f6ed 100644
--- a/lib/Cron/IndexJob.php
+++ b/lib/Cron/IndexJob.php
@@ -39,7 +39,7 @@ class IndexJob extends TimedJob
         $this->setInterval(INTERVAL);
     }
 
-    protected function run($arguments)
+    protected function run($argument)
     {
         // Check if indexing is enabled
         if ('0' === Util::getSystemConfig('memories.index.mode')) {
@@ -47,12 +47,12 @@ class IndexJob extends TimedJob
         }
 
         // Store the last run time
-        $this->config->setAppValue(Application::APPNAME, 'last_index_job_start', time());
-        $this->config->setAppValue(Application::APPNAME, 'last_index_job_duration', 0);
+        $this->config->setAppValue(Application::APPNAME, 'last_index_job_start', (string) time());
+        $this->config->setAppValue(Application::APPNAME, 'last_index_job_duration', (string) 0);
 
         // Run for a maximum of 5 minutes
         $startTime = microtime(true);
-        $this->service->continueCheck = static function () use ($startTime) {
+        $this->service->continueCheck = static function () use ($startTime): bool {
             return (microtime(true) - $startTime) < MAX_RUN_TIME;
         };
 
@@ -81,7 +81,7 @@ class IndexJob extends TimedJob
 
         // Store the last run duration
         $duration = round(microtime(true) - $startTime, 2);
-        $this->config->setAppValue(Application::APPNAME, 'last_index_job_duration', $duration);
+        $this->config->setAppValue(Application::APPNAME, 'last_index_job_duration', (string) $duration);
     }
 
     /**
diff --git a/lib/Db/AddMissingIndices.php b/lib/Db/AddMissingIndices.php
index 977d70eb..dff0051f 100644
--- a/lib/Db/AddMissingIndices.php
+++ b/lib/Db/AddMissingIndices.php
@@ -10,7 +10,7 @@ class AddMissingIndices
     /**
      * Add missing indices to the database schema.
      */
-    public static function run(IOutput $output)
+    public static function run(IOutput $output): SchemaWrapper
     {
         $connection = \OC::$server->get(\OC\DB\Connection::class);
         $schema = new SchemaWrapper($connection);
diff --git a/lib/Db/AlbumsQuery.php b/lib/Db/AlbumsQuery.php
index 8254d388..c025243f 100644
--- a/lib/Db/AlbumsQuery.php
+++ b/lib/Db/AlbumsQuery.php
@@ -22,7 +22,7 @@ class AlbumsQuery
      * @param bool $shared Whether to get shared albums
      * @param int  $fileid File to filter by
      */
-    public function getList(string $uid, bool $shared = false, int $fileid = 0)
+    public function getList(string $uid, bool $shared = false, int $fileid = 0): array
     {
         $query = $this->connection->getQueryBuilder();
 
@@ -234,7 +234,7 @@ class AlbumsQuery
     /**
      * Get list of photos in album.
      */
-    public function getAlbumPhotos(int $albumId, ?int $limit)
+    public function getAlbumPhotos(int $albumId, ?int $limit): array
     {
         $query = $this->connection->getQueryBuilder();
 
@@ -283,8 +283,10 @@ class AlbumsQuery
         return $groups;
     }
 
-    /** Get the name of the collaborators table */
-    private function collaboratorsTable()
+    /**
+     * Get the name of the collaborators table.
+     */
+    private function collaboratorsTable(): string
     {
         // https://github.com/nextcloud/photos/commit/20e3e61ad577014e5f092a292c90a8476f630355
         $appManager = \OC::$server->get(\OCP\App\IAppManager::class);
diff --git a/lib/Db/FsManager.php b/lib/Db/FsManager.php
index 0b3fa186..6c524dbc 100644
--- a/lib/Db/FsManager.php
+++ b/lib/Db/FsManager.php
@@ -74,7 +74,7 @@ class FsManager
      * @param TimelineRoot $root      Root object to populate (by reference)
      * @param bool         $recursive Whether to get the folders recursively
      */
-    public function populateRoot(TimelineRoot &$root, bool $recursive = true)
+    public function populateRoot(TimelineRoot &$root, bool $recursive = true): TimelineRoot
     {
         $user = $this->userSession->getUser();
 
@@ -183,7 +183,7 @@ class FsManager
     /**
      * Get a file with ID for the current user.
      *
-     * @throws Exceptions\NotFoundFile
+     * @throws \OCA\Memories\HttpResponseException
      */
     public function getUserFile(int $fileId): File
     {
@@ -298,7 +298,7 @@ class FsManager
         return null;
     }
 
-    public function getShareObject()
+    public function getShareObject(): ?IShare
     {
         // Get token from request
         $token = $this->getShareToken();
diff --git a/lib/Db/LivePhoto.php b/lib/Db/LivePhoto.php
index 842e1bb3..d101bd41 100644
--- a/lib/Db/LivePhoto.php
+++ b/lib/Db/LivePhoto.php
@@ -18,8 +18,10 @@ class LivePhoto
         $this->connection = $connection;
     }
 
-    /** Check if a given Exif data is the video part of a Live Photo */
-    public function isVideoPart(array $exif)
+    /**
+     * Check if a given Exif data is the video part of a Live Photo.
+     */
+    public function isVideoPart(array $exif): bool
     {
         return \array_key_exists('MIMEType', $exif)
                && 'video/quicktime' === $exif['MIMEType']
diff --git a/lib/Db/TimelineQuery.php b/lib/Db/TimelineQuery.php
index 06242fc9..110de2b8 100644
--- a/lib/Db/TimelineQuery.php
+++ b/lib/Db/TimelineQuery.php
@@ -37,16 +37,19 @@ class TimelineQuery
         $this->request = $request;
     }
 
-    public function allowEmptyRoot(bool $value = true)
+    public function allowEmptyRoot(bool $value = true): void
     {
         $this->_rootEmptyAllowed = $value;
     }
 
-    public function getBuilder()
+    public function getBuilder(): IQueryBuilder
     {
         return $this->connection->getQueryBuilder();
     }
 
+    /**
+     * @return never
+     */
     public static function debugQuery(IQueryBuilder &$query, string $sql = '')
     {
         // Print the query and exit
@@ -58,7 +61,7 @@ class TimelineQuery
         exit; // only for debugging, so this is okay
     }
 
-    public static function replaceQueryParams(IQueryBuilder &$query, string $sql)
+    public static function replaceQueryParams(IQueryBuilder &$query, string $sql): string
     {
         $params = $query->getParameters();
         $platform = $query->getConnection()->getDatabasePlatform();
diff --git a/lib/Db/TimelineQueryDays.php b/lib/Db/TimelineQueryDays.php
index 4f41d5cf..c7981c5f 100644
--- a/lib/Db/TimelineQueryDays.php
+++ b/lib/Db/TimelineQueryDays.php
@@ -57,11 +57,11 @@ trait TimelineQueryDays
     /**
      * Get the day response from the database for the timeline.
      *
-     * @param int[] $day_ids         The day ids to fetch
-     * @param bool  $recursive       If the query should be recursive
-     * @param bool  $archive         If the query should include only the archive folder
-     * @param bool  $hidden          If the query should include hidden files
-     * @param array $queryTransforms The query transformations to apply
+     * @param ?int[] $day_ids         The day ids to fetch
+     * @param bool   $recursive       If the query should be recursive
+     * @param bool   $archive         If the query should include only the archive folder
+     * @param bool   $hidden          If the query should include hidden files
+     * @param array  $queryTransforms The query transformations to apply
      *
      * @return array An array of day responses
      */
@@ -124,7 +124,7 @@ trait TimelineQueryDays
         return $day;
     }
 
-    public function executeQueryWithCTEs(IQueryBuilder $query, string $psql = '')
+    public function executeQueryWithCTEs(IQueryBuilder $query, string $psql = ''): \OCP\DB\IResult
     {
         $sql = empty($psql) ? $query->getSQL() : $psql;
         $params = $query->getParameters();
@@ -211,7 +211,7 @@ trait TimelineQueryDays
      *
      * @param array $days
      */
-    private function processDays($days)
+    private function processDays($days): array
     {
         foreach ($days as &$row) {
             $row['dayid'] = (int) $row['dayid'];
@@ -224,7 +224,7 @@ trait TimelineQueryDays
     /**
      * Process the single day response.
      */
-    private function processDayPhoto(array &$row)
+    private function processDayPhoto(array &$row): void
     {
         // Convert field types
         $row['fileid'] = (int) $row['fileid'];
@@ -278,7 +278,7 @@ trait TimelineQueryDays
         TimelineRoot &$root,
         bool $archive,
         bool $hidden
-    ) {
+    ): void {
         // Add query parameters
         $query->setParameter('topFolderIds', $root->getIds(), IQueryBuilder::PARAM_INT_ARRAY);
 
diff --git a/lib/Db/TimelineQueryFilters.php b/lib/Db/TimelineQueryFilters.php
index 5c31aa18..c7eaa49d 100644
--- a/lib/Db/TimelineQueryFilters.php
+++ b/lib/Db/TimelineQueryFilters.php
@@ -10,7 +10,7 @@ use OCP\ITags;
 
 trait TimelineQueryFilters
 {
-    public function transformFavoriteFilter(IQueryBuilder &$query, bool $aggregate)
+    public function transformFavoriteFilter(IQueryBuilder &$query, bool $aggregate): void
     {
         if (Util::isLoggedIn()) {
             $query->innerJoin('m', 'vcategory_to_object', 'vcoi', $query->expr()->andX(
@@ -20,7 +20,7 @@ trait TimelineQueryFilters
         }
     }
 
-    public function addFavoriteTag(IQueryBuilder &$query)
+    public function addFavoriteTag(IQueryBuilder &$query): void
     {
         if (Util::isLoggedIn()) {
             $query->leftJoin('m', 'vcategory_to_object', 'vco', $query->expr()->andX(
@@ -31,12 +31,12 @@ trait TimelineQueryFilters
         }
     }
 
-    public function transformVideoFilter(IQueryBuilder &$query, bool $aggregate)
+    public function transformVideoFilter(IQueryBuilder &$query, bool $aggregate): void
     {
         $query->andWhere($query->expr()->eq('m.isvideo', $query->expr()->literal(1)));
     }
 
-    public function transformLimit(IQueryBuilder &$query, bool $aggregate, int $limit)
+    public function transformLimit(IQueryBuilder &$query, bool $aggregate, int $limit): void
     {
         if ($limit >= 1 || $limit <= 100) {
             $query->setMaxResults($limit);
diff --git a/lib/Db/TimelineQueryFolders.php b/lib/Db/TimelineQueryFolders.php
index 485fbece..a2d9bae2 100644
--- a/lib/Db/TimelineQueryFolders.php
+++ b/lib/Db/TimelineQueryFolders.php
@@ -17,7 +17,7 @@ trait TimelineQueryFolders
      *
      * @param TimelineRoot $root The root to use for the query
      */
-    public function getRootPreviews(TimelineRoot $root)
+    public function getRootPreviews(TimelineRoot $root): array
     {
         $query = $this->connection->getQueryBuilder();
 
diff --git a/lib/Db/TimelineQueryLivePhoto.php b/lib/Db/TimelineQueryLivePhoto.php
index e52cfa77..c216aff6 100644
--- a/lib/Db/TimelineQueryLivePhoto.php
+++ b/lib/Db/TimelineQueryLivePhoto.php
@@ -6,7 +6,7 @@ namespace OCA\Memories\Db;
 
 trait TimelineQueryLivePhoto
 {
-    public function getLivePhotos(int $fileid)
+    public function getLivePhotos(int $fileid): array
     {
         $qb = $this->connection->getQueryBuilder();
         $qb->select('lp.fileid', 'lp.liveid')
diff --git a/lib/Db/TimelineQueryMap.php b/lib/Db/TimelineQueryMap.php
index 58a66bef..694c922c 100644
--- a/lib/Db/TimelineQueryMap.php
+++ b/lib/Db/TimelineQueryMap.php
@@ -13,7 +13,7 @@ trait TimelineQueryMap
 
     protected IDBConnection $connection;
 
-    public function transformMapBoundsFilter(IQueryBuilder &$query, bool $aggregate, string $bounds, string $table = 'm')
+    public function transformMapBoundsFilter(IQueryBuilder &$query, bool $aggregate, string $bounds, string $table = 'm'): void
     {
         $bounds = explode(',', $bounds);
         $bounds = array_map('floatval', $bounds);
@@ -84,7 +84,7 @@ trait TimelineQueryMap
         return $clusters;
     }
 
-    public function getMapClusterPreviews(array $clusterIds)
+    public function getMapClusterPreviews(array $clusterIds): array
     {
         $query = $this->connection->getQueryBuilder();
 
diff --git a/lib/Db/TimelineQueryNativeX.php b/lib/Db/TimelineQueryNativeX.php
index 8e355746..4eab3db9 100644
--- a/lib/Db/TimelineQueryNativeX.php
+++ b/lib/Db/TimelineQueryNativeX.php
@@ -8,7 +8,7 @@ use OCP\DB\QueryBuilder\IQueryBuilder;
 
 trait TimelineQueryNativeX
 {
-    public function transformNativeQuery(IQueryBuilder &$query, bool $aggregate)
+    public function transformNativeQuery(IQueryBuilder &$query, bool $aggregate): void
     {
         if (!$aggregate) {
             $query->addSelect('m.epoch', 'f.size', 'm.buid');
diff --git a/lib/Db/TimelineRoot.php b/lib/Db/TimelineRoot.php
index 5544ce1d..501287f9 100644
--- a/lib/Db/TimelineRoot.php
+++ b/lib/Db/TimelineRoot.php
@@ -23,7 +23,7 @@ class TimelineRoot
      *
      * @throws \Exception if node is not valid readable folder
      */
-    public function addFolder(FileInfo $info)
+    public function addFolder(FileInfo $info): void
     {
         $path = $info->getPath();
 
@@ -42,7 +42,7 @@ class TimelineRoot
     /**
      * Add mountpoints recursively.
      */
-    public function addMountPoints()
+    public function addMountPoints(): void
     {
         $manager = \OC\Files\Filesystem::getMountManager();
         foreach ($this->folderPaths as $id => $folderPath) {
@@ -67,7 +67,7 @@ class TimelineRoot
      *
      * @param string[] $paths The paths to exclude
      */
-    public function excludePaths(array $paths)
+    public function excludePaths(array $paths): void
     {
         foreach ($paths as $path) {
             foreach ($this->folderPaths as $id => $folderPath) {
@@ -87,7 +87,7 @@ class TimelineRoot
      *
      * @param string $path The new base path
      */
-    public function baseChange(string $path)
+    public function baseChange(string $path): void
     {
         foreach ($this->folderPaths as $id => $folderPath) {
             if (!str_starts_with($folderPath.'/', $path.'/')) {
@@ -101,11 +101,17 @@ class TimelineRoot
         return $this->folderPaths[$id];
     }
 
-    public function getIds()
+    /**
+     * @return int[]
+     */
+    public function getIds(): array
     {
         return array_keys($this->folderPaths);
     }
 
+    /**
+     * @return null|int
+     */
     public function getOneId()
     {
         return array_key_first($this->folders);
@@ -116,12 +122,12 @@ class TimelineRoot
         return $this->folders[$id];
     }
 
-    public function isEmpty()
+    public function isEmpty(): bool
     {
         return empty($this->folderPaths);
     }
 
-    private function setFolder(int $id, ?FileInfo $fileInfo, ?string $path)
+    private function setFolder(int $id, ?FileInfo $fileInfo, ?string $path): void
     {
         if (null !== $path) {
             $this->folderPaths[$id] = $path;
diff --git a/lib/Db/TimelineWrite.php b/lib/Db/TimelineWrite.php
index a7cbc6cd..7281a45f 100644
--- a/lib/Db/TimelineWrite.php
+++ b/lib/Db/TimelineWrite.php
@@ -192,7 +192,7 @@ class TimelineWrite
     /**
      * Remove a file from the exif database.
      */
-    public function deleteFile(File &$file)
+    public function deleteFile(File &$file): void
     {
         // Get full record
         $query = $this->connection->getQueryBuilder();
@@ -255,7 +255,7 @@ class TimelineWrite
     /**
      * Clear the entire index. Does not need confirmation!
      */
-    public function clear()
+    public function clear(): void
     {
         $p = $this->connection->getDatabasePlatform();
         foreach (array_merge(DELETE_TABLES, TRUNCATE_TABLES) as $table) {
diff --git a/lib/Db/TimelineWriteOrphans.php b/lib/Db/TimelineWriteOrphans.php
index 6e842102..2554663a 100644
--- a/lib/Db/TimelineWriteOrphans.php
+++ b/lib/Db/TimelineWriteOrphans.php
@@ -22,7 +22,7 @@ trait TimelineWriteOrphans
      */
     public function orphanAll(bool $value = true, ?array $fileIds = null, bool $onlyMain = false): int
     {
-        $do = function (string $table) use ($value, $fileIds) {
+        $do = function (string $table) use ($value, $fileIds): int {
             $query = $this->connection->getQueryBuilder();
             $query->update($table)
                 ->set('orphan', $query->createNamedParameter($value, IQueryBuilder::PARAM_BOOL))
@@ -51,7 +51,7 @@ trait TimelineWriteOrphans
      * @param int      $txnSize  number of rows to process in a single transaction
      * @param \Closure $callback will be passed each row
      */
-    public function orphanAndRun(array $fields, int $txnSize, \Closure $callback)
+    public function orphanAndRun(array $fields, int $txnSize, \Closure $callback): void
     {
         // Orphan all files. This means if we are interrupted,
         // it will lead to a re-index of the whole library!
diff --git a/lib/Db/TimelineWritePlaces.php b/lib/Db/TimelineWritePlaces.php
index 57a7b24b..0546bf22 100644
--- a/lib/Db/TimelineWritePlaces.php
+++ b/lib/Db/TimelineWritePlaces.php
@@ -156,8 +156,12 @@ trait TimelineWritePlaces
      * Read coordinates from array and round to 6 decimal places.
      *
      * Modifies the array to remove invalid coordinates.
+     *
+     * @return (null|float)[]
+     *
+     * @psalm-return list{float|null, float|null}
      */
-    private static function readCoord(array &$exif)
+    private static function readCoord(array &$exif): array
     {
         $lat = \array_key_exists(LAT_KEY, $exif) ? round((float) $exif[LAT_KEY], 6) : null;
         $lon = \array_key_exists(LON_KEY, $exif) ? round((float) $exif[LON_KEY], 6) : null;
diff --git a/lib/Exif.php b/lib/Exif.php
index e96222d6..d1334df1 100644
--- a/lib/Exif.php
+++ b/lib/Exif.php
@@ -19,7 +19,7 @@ class Exif
     private static $staticPipes;
     private static $noStaticProc = false;
 
-    public static function closeStaticExiftoolProc()
+    public static function closeStaticExiftoolProc(): void
     {
         try {
             if (self::$staticProc) {
@@ -35,13 +35,13 @@ class Exif
         }
     }
 
-    public static function restartStaticExiftoolProc()
+    public static function restartStaticExiftoolProc(): void
     {
         self::closeStaticExiftoolProc();
         self::ensureStaticExiftoolProc();
     }
 
-    public static function ensureStaticExiftoolProc()
+    public static function ensureStaticExiftoolProc(): void
     {
         if (self::$noStaticProc) {
             return;
@@ -68,7 +68,7 @@ class Exif
     /**
      * Get exif data as a JSON object from a Nextcloud file.
      */
-    public static function getExifFromFile(File $file)
+    public static function getExifFromFile(File $file): array
     {
         try {
             $path = $file->getStorage()->getLocalFile($file->getInternalPath());
@@ -106,8 +106,10 @@ class Exif
         return $exif;
     }
 
-    /** Get exif data as a JSON object from a local file path */
-    public static function getExifFromLocalPath(string $path)
+    /**
+     * Get exif data as a JSON object from a local file path.
+     */
+    public static function getExifFromLocalPath(string $path): array
     {
         if (null !== self::$staticProc) {
             self::ensureStaticExiftoolProc();
@@ -298,7 +300,7 @@ class Exif
      *
      * @throws \Exception on failure
      */
-    public static function setExif(string $path, array $data)
+    public static function setExif(string $path, array $data): void
     {
         $data['SourceFile'] = $path;
         $raw = json_encode([$data], JSON_UNESCAPED_UNICODE);
@@ -328,7 +330,7 @@ class Exif
         }
     }
 
-    public static function setFileExif(File $file, array $data)
+    public static function setFileExif(File $file, array $data): void
     {
         // Get path to local file so we can skip reading
         $path = $file->getStorage()->getLocalFile($file->getInternalPath());
@@ -345,7 +347,7 @@ class Exif
         $file->touch();
     }
 
-    public static function getBinaryExifProp(string $path, string $prop)
+    public static function getBinaryExifProp(string $path, string $prop): string
     {
         $pipes = [];
         $proc = proc_open(array_merge(self::getExiftool(), [$prop, '-n', '-b', $path]), [
@@ -368,7 +370,7 @@ class Exif
         }
     }
 
-    public static function getExifWithDuplicates(string $path)
+    public static function getExifWithDuplicates(string $path): array
     {
         return self::getExifFromLocalPathWithSeparateProc($path, ['-U', '-G4']);
     }
@@ -378,8 +380,10 @@ class Exif
         return BinExt::getExiftool();
     }
 
-    /** Initialize static exiftool process for local reads */
-    private static function initializeStaticExiftoolProc()
+    /**
+     * Initialize static exiftool process for local reads.
+     */
+    private static function initializeStaticExiftoolProc(): void
     {
         self::closeStaticExiftoolProc();
         self::$staticProc = proc_open(array_merge(self::getExiftool(), ['-stay_open', 'true', '-@', '-']), [
@@ -397,7 +401,7 @@ class Exif
      * @param int      $timeout   milliseconds
      * @param string   $delimiter null for eof
      */
-    private static function readOrTimeout($handle, int $timeout, ?string $delimiter = null)
+    private static function readOrTimeout($handle, int $timeout, ?string $delimiter = null): string
     {
         $buf = '';
         $waitedMs = 0;
@@ -420,7 +424,7 @@ class Exif
         return $buf;
     }
 
-    private static function getExifFromLocalPathWithStaticProc(string $path)
+    private static function getExifFromLocalPathWithStaticProc(string $path): array
     {
         $args = implode("\n", self::EXIFTOOL_ARGS);
         fwrite(self::$staticPipes[0], "{$path}\n{$args}\n-execute\n");
@@ -442,7 +446,7 @@ class Exif
         }
     }
 
-    private static function getExifFromLocalPathWithSeparateProc(string $path, array $extraArgs = [])
+    private static function getExifFromLocalPathWithSeparateProc(string $path, array $extraArgs = []): array
     {
         $pipes = [];
         $proc = proc_open(array_merge(self::getExiftool(), self::EXIFTOOL_ARGS, $extraArgs, [$path]), [
@@ -468,7 +472,7 @@ class Exif
     }
 
     /** Get json array from stdout of exiftool */
-    private static function processStdout(string $stdout)
+    private static function processStdout(string $stdout): array
     {
         $json = json_decode($stdout, true);
         if (!$json) {
diff --git a/lib/Listeners/BeforeTemplateListener.php b/lib/Listeners/BeforeTemplateListener.php
index fd8f20b7..f1283b70 100644
--- a/lib/Listeners/BeforeTemplateListener.php
+++ b/lib/Listeners/BeforeTemplateListener.php
@@ -26,6 +26,9 @@ use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
 use OCP\ISession;
 
+/**
+ * @template-implements IEventListener<Event>
+ */
 class BeforeTemplateListener implements IEventListener
 {
     private ISession $session;
diff --git a/lib/Listeners/PostDeleteListener.php b/lib/Listeners/PostDeleteListener.php
index d2bf80e3..23d9db66 100644
--- a/lib/Listeners/PostDeleteListener.php
+++ b/lib/Listeners/PostDeleteListener.php
@@ -27,6 +27,9 @@ use OCP\EventDispatcher\IEventListener;
 use OCP\Files\Events\Node\NodeDeletedEvent;
 use OCP\Files\Folder;
 
+/**
+ * @template-implements IEventListener<Event>
+ */
 class PostDeleteListener implements IEventListener
 {
     private TimelineWrite $util;
diff --git a/lib/Listeners/PostLogoutListener.php b/lib/Listeners/PostLogoutListener.php
index a4d1d131..44dd8060 100644
--- a/lib/Listeners/PostLogoutListener.php
+++ b/lib/Listeners/PostLogoutListener.php
@@ -25,6 +25,9 @@ use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
 use OCP\ISession;
 
+/**
+ * @template-implements IEventListener<Event>
+ */
 class PostLogoutListener implements IEventListener
 {
     public const CLEAR_CACHE_KEY = 'memories_clear_cache';
diff --git a/lib/Listeners/PostWriteListener.php b/lib/Listeners/PostWriteListener.php
index 9fca2e6e..937e11e2 100644
--- a/lib/Listeners/PostWriteListener.php
+++ b/lib/Listeners/PostWriteListener.php
@@ -29,6 +29,9 @@ use OCP\Files\Events\Node\NodeTouchedEvent;
 use OCP\Files\Events\Node\NodeWrittenEvent;
 use Psr\Log\LoggerInterface;
 
+/**
+ * @template-implements IEventListener<Event>
+ */
 class PostWriteListener implements IEventListener
 {
     private TimelineWrite $timelineWrite;
diff --git a/lib/Service/BinExt.php b/lib/Service/BinExt.php
index b6722898..bbbd406e 100644
--- a/lib/Service/BinExt.php
+++ b/lib/Service/BinExt.php
@@ -164,7 +164,7 @@ class BinExt
         return "http://{$connect}/{$client}{$path}/{$profile}";
     }
 
-    public static function getGoVodConfig($local = false)
+    public static function getGoVodConfig(bool $local = false): array
     {
         // Get config from system values
         $env = [
@@ -205,7 +205,7 @@ class BinExt
     /**
      * Get temp binary for go-vod.
      */
-    public static function getGoVodBin()
+    public static function getGoVodBin(): string
     {
         $path = Util::getSystemConfig('memories.vod.path');
 
@@ -332,8 +332,10 @@ class BinExt
         return $version;
     }
 
-    /** POST a new configuration to go-vod */
-    public static function configureGoVod()
+    /**
+     * POST a new configuration to go-vod.
+     */
+    public static function configureGoVod(): bool
     {
         // Get config
         $config = self::getGoVodConfig();
@@ -412,7 +414,7 @@ class BinExt
         return $ffmpegPath;
     }
 
-    public static function testFFmpeg(string $path, string $name)
+    public static function testFFmpeg(string $path, string $name): string
     {
         $version = shell_exec("{$path} -version");
         if (!preg_match("/{$name} version \\S*/", $version, $matches)) {
@@ -422,12 +424,12 @@ class BinExt
         return explode(' ', $matches[0])[2];
     }
 
-    public static function testSystemPerl(string $path): string
+    public static function testSystemPerl(string $path): ?string
     {
         if (($out = shell_exec("{$path} -e 'print \"OK\";'")) !== 'OK') {
             throw new \Exception('Failed to run test perl script: '.$out);
         }
 
-        return shell_exec("{$path} -e 'print $^V;'");
+        return shell_exec("{$path} -e 'print $^V;'") ?: null;
     }
 }
diff --git a/lib/Service/FileRobotMagick.php b/lib/Service/FileRobotMagick.php
index e247a39f..a764b491 100644
--- a/lib/Service/FileRobotMagick.php
+++ b/lib/Service/FileRobotMagick.php
@@ -123,7 +123,7 @@ class FileRobotImageState
         }
     }
 
-    private function _set(array $parent, string $key, string $ckey = null)
+    private function _set(array $parent, string $key, string $ckey = null): void
     {
         $ckey ??= $key;
         if (\array_key_exists($key, $parent)) {
@@ -146,7 +146,7 @@ class FileRobotMagick
         $this->state = new FileRobotImageState($state);
     }
 
-    public function apply()
+    public function apply(): \Imagick
     {
         // Ensure the image is in the correct colorspace
         if (\Imagick::COLORSPACE_SRGB !== $this->image->getColorspace()) {
@@ -179,7 +179,7 @@ class FileRobotMagick
         return $this->image;
     }
 
-    protected function applyCrop()
+    protected function applyCrop(): void
     {
         if ($this->state->cropX || $this->state->cropY || $this->state->cropWidth || $this->state->cropHeight) {
             $iw = $this->image->getImageWidth();
@@ -193,7 +193,7 @@ class FileRobotMagick
         }
     }
 
-    protected function applyFlipRotation()
+    protected function applyFlipRotation(): void
     {
         if ($this->state->isFlippedX) {
             $this->image->flopImage();
@@ -206,7 +206,7 @@ class FileRobotMagick
         }
     }
 
-    protected function applyResize()
+    protected function applyResize(): void
     {
         if ($this->state->resizeWidth || $this->state->resizeHeight) {
             $this->image->resizeImage(
@@ -218,7 +218,7 @@ class FileRobotMagick
         }
     }
 
-    protected function applyBrighten(?float $value = null)
+    protected function applyBrighten(?float $value = null): void
     {
         $brightness = $value ?? $this->state->brightness ?? 0;
         if (0 === $brightness) {
@@ -229,7 +229,7 @@ class FileRobotMagick
         $this->image->evaluateImage(\Imagick::EVALUATE_ADD, $brightness * 255 * 255, \Imagick::CHANNEL_ALL);
     }
 
-    protected function applyContrast(?float $value = null)
+    protected function applyContrast(?float $value = null): void
     {
         $contrast = $value ?? $this->state->contrast ?? 0;
         if (0 === $contrast) {
@@ -246,7 +246,7 @@ class FileRobotMagick
         $this->image->functionImage(\Imagick::FUNCTION_POLYNOMIAL, [$m, $c], \Imagick::CHANNEL_ALL);
     }
 
-    protected function applyHSV(?float $hue = null, ?float $saturation = null, ?float $value = null)
+    protected function applyHSV(?float $hue = null, ?float $saturation = null, ?float $value = null): void
     {
         $hue ??= $this->state->hue ?? 0;
         $saturation ??= $this->state->saturation ?? 0;
@@ -274,18 +274,17 @@ class FileRobotMagick
         $bg = 0.587 * $v - 0.586 * $vsu - 1.05 * $vsw;
         $bb = 0.114 * $v + 0.886 * $vsu - 0.2 * $vsw;
 
-        $colorMatrix = [
+        /** @psalm-suppress InvalidArgument */
+        $this->image->colorMatrixImage([
             $rr, $rg, $rb, 0, 0,
             $gr, $gg, $gb, 0, 0,
             $br, $bg, $bb, 0, 0,
             0, 0, 0, 1, 0,
             0, 0, 0, 0, 1,
-        ];
-
-        $this->image->colorMatrixImage($colorMatrix);
+        ]);
     }
 
-    protected function applyBlur()
+    protected function applyBlur(): void
     {
         if ($this->state->blurRadius <= 0) {
             return;
@@ -296,7 +295,7 @@ class FileRobotMagick
         $this->image->blurImage(0, $sigma);
     }
 
-    protected function applyWarmth()
+    protected function applyWarmth(): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/finetunes/Warmth.js#L17-L28
         $warmth = ($this->state->warmth ?? 0);
@@ -310,20 +309,21 @@ class FileRobotMagick
     }
 
     // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/components/tools/Filters/Filters.constants.js#L8
-    protected function applyFilterInvert()
+    protected function applyFilterInvert(): void
     {
         $this->image->negateImage(false);
     }
 
-    protected function applyFilterBlackAndWhite()
+    protected function applyFilterBlackAndWhite(): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BlackAndWhite.js
         $this->image->thresholdImage(100 * 255);
     }
 
-    protected function applyFilterSepia()
+    protected function applyFilterSepia(): void
     {
         // https://github.com/konvajs/konva/blob/master/src/filters/Sepia.ts
+        /** @psalm-suppress InvalidArgument */
         $this->image->colorMatrixImage([
             0.393, 0.769, 0.189, 0, 0,
             0.349, 0.686, 0.168, 0, 0,
@@ -333,267 +333,267 @@ class FileRobotMagick
         ]);
     }
 
-    protected function applyFilterSolarize()
+    protected function applyFilterSolarize(): void
     {
         // https://github.com/konvajs/konva/blob/master/src/filters/Solarize.ts
         $this->image->solarizeImage(128 * 255);
     }
 
-    protected function applyFilterClarendon()
+    protected function applyFilterClarendon(): void
     {
         $this->applyBaseFilterBrightness(0.1);
         $this->applyBaseFilterContrast(0.1);
         $this->applyBaseFilterSaturation(0.15);
     }
 
-    protected function applyFilterGingham()
+    protected function applyFilterGingham(): void
     {
         $this->applyBaseFilterSepia(0.04);
         $this->applyBaseFilterContrast(-0.15);
     }
 
-    protected function applyFilterMoon()
+    protected function applyFilterMoon(): void
     {
         $this->applyBaseFilterGrayscale();
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterLark()
+    protected function applyFilterLark(): void
     {
         $this->applyBaseFilterBrightness(0.08);
         $this->applyBaseFilterAdjustRGB(1, 1.03, 1.05);
         $this->applyBaseFilterSaturation(0.12);
     }
 
-    protected function applyFilterReyes()
+    protected function applyFilterReyes(): void
     {
         $this->applyBaseFilterSepia(0.4);
         $this->applyBaseFilterBrightness(0.13);
         $this->applyBaseFilterContrast(-0.05);
     }
 
-    protected function applyFilterJuno()
+    protected function applyFilterJuno(): void
     {
         $this->applyBaseFilterAdjustRGB(1.01, 1.04, 1);
         $this->applyBaseFilterSaturation(0.3);
     }
 
-    protected function applyFilterSlumber()
+    protected function applyFilterSlumber(): void
     {
         $this->applyBaseFilterBrightness(0.1);
         $this->applyBaseFilterSaturation(-0.5);
     }
 
-    protected function applyFilterCrema()
+    protected function applyFilterCrema(): void
     {
         $this->applyBaseFilterAdjustRGB(1.04, 1, 1.02);
         $this->applyBaseFilterSaturation(-0.05);
     }
 
-    protected function applyFilterLudwig()
+    protected function applyFilterLudwig(): void
     {
         $this->applyBaseFilterBrightness(0.05);
         $this->applyBaseFilterSaturation(-0.03);
     }
 
-    protected function applyFilterAden()
+    protected function applyFilterAden(): void
     {
         $this->applyBaseFilterColorFilter(228, 130, 225, 0.13);
         $this->applyBaseFilterSaturation(-0.2);
     }
 
-    protected function applyFilterPerpetua()
+    protected function applyFilterPerpetua(): void
     {
         $this->applyBaseFilterAdjustRGB(1.05, 1.1, 1);
     }
 
-    protected function applyFilterAmaro()
+    protected function applyFilterAmaro(): void
     {
         $this->applyBaseFilterSaturation(0.3);
         $this->applyBaseFilterBrightness(0.15);
     }
 
-    protected function applyFilterMayfair()
+    protected function applyFilterMayfair(): void
     {
         $this->applyBaseFilterColorFilter(230, 115, 108, 0.05);
         $this->applyBaseFilterSaturation(0.15);
     }
 
-    protected function applyFilterRise()
+    protected function applyFilterRise(): void
     {
         $this->applyBaseFilterColorFilter(255, 170, 0, 0.1);
         $this->applyBaseFilterBrightness(0.09);
         $this->applyBaseFilterSaturation(0.1);
     }
 
-    protected function applyFilterHudson()
+    protected function applyFilterHudson(): void
     {
         $this->applyBaseFilterAdjustRGB(1, 1, 1.25);
         $this->applyBaseFilterContrast(0.1);
         $this->applyBaseFilterBrightness(0.15);
     }
 
-    protected function applyFilterValencia()
+    protected function applyFilterValencia(): void
     {
         $this->applyBaseFilterColorFilter(255, 225, 80, 0.08);
         $this->applyBaseFilterSaturation(0.1);
         $this->applyBaseFilterContrast(0.05);
     }
 
-    protected function applyFilterXpro2()
+    protected function applyFilterXpro2(): void
     {
         $this->applyBaseFilterColorFilter(255, 255, 0, 0.07);
         $this->applyBaseFilterSaturation(0.2);
         $this->applyBaseFilterContrast(0.15);
     }
 
-    protected function applyFilterSierra()
+    protected function applyFilterSierra(): void
     {
         $this->applyBaseFilterContrast(-0.15);
         $this->applyBaseFilterSaturation(0.1);
     }
 
-    protected function applyFilterWillow()
+    protected function applyFilterWillow(): void
     {
         $this->applyBaseFilterGrayscale();
         $this->applyBaseFilterColorFilter(100, 28, 210, 0.03);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterLoFi()
+    protected function applyFilterLoFi(): void
     {
         $this->applyBaseFilterContrast(0.15);
         $this->applyBaseFilterSaturation(0.2);
     }
 
-    protected function applyFilterInkwell()
+    protected function applyFilterInkwell(): void
     {
         $this->applyBaseFilterGrayscale();
     }
 
-    protected function applyFilterHefe()
+    protected function applyFilterHefe(): void
     {
         $this->applyBaseFilterContrast(0.1);
         $this->applyBaseFilterSaturation(0.15);
     }
 
-    protected function applyFilterNashville()
+    protected function applyFilterNashville(): void
     {
         $this->applyBaseFilterColorFilter(220, 115, 188, 0.12);
         $this->applyBaseFilterContrast(-0.05);
     }
 
-    protected function applyFilterStinson()
+    protected function applyFilterStinson(): void
     {
         $this->applyBaseFilterBrightness(0.1);
         $this->applyBaseFilterSepia(0.3);
     }
 
-    protected function applyFilterVesper()
+    protected function applyFilterVesper(): void
     {
         $this->applyBaseFilterColorFilter(255, 225, 0, 0.05);
         $this->applyBaseFilterBrightness(0.06);
         $this->applyBaseFilterContrast(0.06);
     }
 
-    protected function applyFilterEarlybird()
+    protected function applyFilterEarlybird(): void
     {
         $this->applyBaseFilterColorFilter(255, 165, 40, 0.2);
     }
 
-    protected function applyFilterBrannan()
+    protected function applyFilterBrannan(): void
     {
         $this->applyBaseFilterContrast(0.2);
         $this->applyBaseFilterColorFilter(140, 10, 185, 0.1);
     }
 
-    protected function applyFilterSutro()
+    protected function applyFilterSutro(): void
     {
         $this->applyBaseFilterBrightness(-0.1);
         $this->applyBaseFilterContrast(-0.1);
     }
 
-    protected function applyFilterToaster()
+    protected function applyFilterToaster(): void
     {
         $this->applyBaseFilterSepia(0.1);
         $this->applyBaseFilterColorFilter(255, 145, 0, 0.2);
     }
 
-    protected function applyFilterWalden()
+    protected function applyFilterWalden(): void
     {
         $this->applyBaseFilterBrightness(0.1);
         $this->applyBaseFilterColorFilter(255, 255, 0, 0.2);
     }
 
-    protected function applyFilterNinteenSeventySeven()
+    protected function applyFilterNinteenSeventySeven(): void
     {
         $this->applyBaseFilterColorFilter(255, 25, 0, 0.15);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterKelvin()
+    protected function applyFilterKelvin(): void
     {
         $this->applyBaseFilterColorFilter(255, 140, 0, 0.1);
         $this->applyBaseFilterAdjustRGB(1.15, 1.05, 1);
         $this->applyBaseFilterSaturation(0.35);
     }
 
-    protected function applyFilterMaven()
+    protected function applyFilterMaven(): void
     {
         $this->applyBaseFilterColorFilter(225, 240, 0, 0.1);
         $this->applyBaseFilterSaturation(0.25);
         $this->applyBaseFilterContrast(0.05);
     }
 
-    protected function applyFilterGinza()
+    protected function applyFilterGinza(): void
     {
         $this->applyBaseFilterSepia(0.06);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterSkyline()
+    protected function applyFilterSkyline(): void
     {
         $this->applyBaseFilterSaturation(0.35);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterDogpatch()
+    protected function applyFilterDogpatch(): void
     {
         $this->applyBaseFilterContrast(0.15);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterBrooklyn()
+    protected function applyFilterBrooklyn(): void
     {
         $this->applyBaseFilterColorFilter(25, 240, 252, 0.05);
         $this->applyBaseFilterSepia(0.3);
     }
 
-    protected function applyFilterHelena()
+    protected function applyFilterHelena(): void
     {
         $this->applyBaseFilterColorFilter(208, 208, 86, 0.2);
         $this->applyBaseFilterContrast(0.15);
     }
 
-    protected function applyFilterAshby()
+    protected function applyFilterAshby(): void
     {
         $this->applyBaseFilterColorFilter(255, 160, 25, 0.1);
         $this->applyBaseFilterBrightness(0.1);
     }
 
-    protected function applyFilterCharmes()
+    protected function applyFilterCharmes(): void
     {
         $this->applyBaseFilterColorFilter(255, 50, 80, 0.12);
         $this->applyBaseFilterContrast(0.05);
     }
 
-    protected function applyBaseFilterBrightness(float $value)
+    protected function applyBaseFilterBrightness(float $value): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L2
         $this->applyBrighten($value);
     }
 
-    protected function applyBaseFilterContrast(float $value)
+    protected function applyBaseFilterContrast(float $value): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L14
         $value *= 255;
@@ -606,16 +606,17 @@ class FileRobotMagick
         $this->image->functionImage(\Imagick::FUNCTION_POLYNOMIAL, [$m, $c], \Imagick::CHANNEL_ALL);
     }
 
-    protected function applyBaseFilterSaturation(float $value)
+    protected function applyBaseFilterSaturation(float $value): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L24
         $this->applyHSV(0, $value, 0); // lazy
     }
 
-    protected function applyBaseFilterGrayscale()
+    protected function applyBaseFilterGrayscale(): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L38
         //  y = 0.2126 * r + 0.7152 * g + 0.0722 * b;
+        /** @psalm-suppress InvalidArgument */
         $this->image->colorMatrixImage([
             0.2126, 0.7152, 0.0722, 0, 0,
             0.2126, 0.7152, 0.0722, 0, 0,
@@ -625,9 +626,10 @@ class FileRobotMagick
         ]);
     }
 
-    protected function applyBaseFilterSepia(float $value)
+    protected function applyBaseFilterSepia(float $value): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L46
+        /** @psalm-suppress InvalidArgument */
         $this->image->colorMatrixImage([
             1 - 0.607 * $value, 0.769 * $value, 0.189 * $value, 0, 0,
             0.349 * $value, 1 - 0.314 * $value, 0.168 * $value, 0, 0,
@@ -637,9 +639,10 @@ class FileRobotMagick
         ]);
     }
 
-    protected function applyBaseFilterAdjustRGB(float $r, float $g, float $b)
+    protected function applyBaseFilterAdjustRGB(float $r, float $g, float $b): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L57
+        /** @psalm-suppress InvalidArgument */
         $this->image->colorMatrixImage([
             $r, 0, 0, 0, 0,
             0, $g, 0, 0, 0,
@@ -649,7 +652,7 @@ class FileRobotMagick
         ]);
     }
 
-    protected function applyBaseFilterColorFilter(float $r, float $g, float $b, float $v)
+    protected function applyBaseFilterColorFilter(float $r, float $g, float $b, float $v): void
     {
         // https://github.com/scaleflex/filerobot-image-editor/blob/7113bf4968d97f41381f4a2965a59defd44562c8/packages/react-filerobot-image-editor/src/custom/filters/BaseFilters.js#L63
         // y = x - (x - k) * v = (1 - v) * x + k * v
diff --git a/lib/Service/Index.php b/lib/Service/Index.php
index 9d5123f0..da095fd5 100644
--- a/lib/Service/Index.php
+++ b/lib/Service/Index.php
@@ -153,7 +153,7 @@ class Index
             ;
 
             // Filter out files that are already indexed
-            $addFilter = static function (string $table, string $alias) use (&$query) {
+            $addFilter = static function (string $table, string $alias) use (&$query): void {
                 $query->leftJoin('f', $table, $alias, $query->expr()->andX(
                     $query->expr()->eq('f.fileid', "{$alias}.fileid"),
                     $query->expr()->eq('f.mtime', "{$alias}.mtime"),
@@ -224,7 +224,7 @@ class Index
     /**
      * Get total number of files that are indexed.
      */
-    public function getIndexedCount()
+    public function getIndexedCount(): int
     {
         $query = $this->db->getQueryBuilder();
         $query->select($query->createFunction('COUNT(DISTINCT fileid)'))
@@ -282,8 +282,10 @@ class Index
         return \in_array($file->getMimeType(), Application::VIDEO_MIMES, true);
     }
 
-    /** Log to console if CLI or logger */
-    private function error(string $message)
+    /**
+     * Log error to console if CLI or logger.
+     */
+    private function error(string $message): void
     {
         $this->logger->error($message);
 
@@ -292,8 +294,10 @@ class Index
         }
     }
 
-    /** Log to console if CLI */
-    private function log(string $message, bool $overwrite = false)
+    /**
+     * Log to console if CLI.
+     */
+    private function log(string $message, bool $overwrite = false): void
     {
         if ($this->output) {
             if ($overwrite) {
diff --git a/lib/Service/Places.php b/lib/Service/Places.php
index 4ed5cfdc..41462ffd 100644
--- a/lib/Service/Places.php
+++ b/lib/Service/Places.php
@@ -34,8 +34,10 @@ class Places
 
     /**
      * Make SQL query to detect GIS type.
+     *
+     * @psalm-return 0|1|2
      */
-    public function detectGisType()
+    public function detectGisType(): int
     {
         // Make sure database prefix is set
         $prefix = $this->config->getSystemValue('dbtableprefix', '') ?: '';
@@ -83,7 +85,7 @@ class Places
     public function geomCount(): int
     {
         try {
-            return $this->connection->executeQuery('SELECT COUNT(osm_id) as c FROM memories_planet_geometry')->fetchOne();
+            return (int) $this->connection->executeQuery('SELECT COUNT(osm_id) as c FROM memories_planet_geometry')->fetchOne();
         } catch (\Exception $e) {
             return 0;
         }
@@ -244,7 +246,7 @@ class Places
         $txnCount = 0;
 
         // Function to commit the current transaction
-        $transact = function () use (&$txnCount) {
+        $transact = function () use (&$txnCount): void {
             if (++$txnCount >= DB_TRANSACTION_SIZE) {
                 $this->connection->commit();
                 $this->connection->beginTransaction();
@@ -379,7 +381,7 @@ class Places
     /**
      * Recalculate all places for all users.
      */
-    public function recalculateAll()
+    public function recalculateAll(): void
     {
         echo "Recalculating places for all files (do not interrupt this process)...\n";
         flush();
diff --git a/lib/Util.php b/lib/Util.php
index 62650bb7..a9934d05 100644
--- a/lib/Util.php
+++ b/lib/Util.php
@@ -12,7 +12,6 @@ use OCP\App\IAppManager;
 use OCP\Files\Node;
 use OCP\Files\Search\ISearchBinaryOperator;
 use OCP\Files\Search\ISearchComparison;
-use OCP\IAppConfig;
 use OCP\IConfig;
 
 class Util
@@ -23,8 +22,10 @@ class Util
 
     /**
      * Get host CPU architecture (amd64 or aarch64).
+     *
+     * @psalm-return 'aarch64'|'amd64'|null
      */
-    public static function getArch()
+    public static function getArch(): ?string
     {
         $uname = php_uname('m');
         if (false !== stripos($uname, 'aarch64') || false !== stripos($uname, 'arm64')) {
@@ -39,8 +40,10 @@ class Util
 
     /**
      * Get the libc type for host (glibc or musl).
+     *
+     * @psalm-return 'glibc'|'musl'|null
      */
-    public static function getLibc()
+    public static function getLibc(): ?string
     {
         if ($ldd = shell_exec('ldd --version 2>&1')) {
             if (false !== stripos($ldd, 'musl')) {
@@ -89,8 +92,8 @@ class Util
             return false;
         }
 
-        $config = \OC::$server->get(IAppConfig::class);
-        if ('true' !== $config->getValue('recognize', 'faces.enabled', 'false')) {
+        $config = \OC::$server->get(IConfig::class);
+        if ('true' !== $config->getAppValue('recognize', 'faces.enabled', 'false')) {
             return false;
         }
 
@@ -192,10 +195,12 @@ class Util
      * @param mixed $key   Key to set
      * @param mixed $value Value to set
      */
-    public static function forceFileInfo(Node &$node, $key, $value)
+    public static function forceFileInfo(Node &$node, $key, $value): void
     {
         /** @var \OC\Files\Node\Node */
         $node = $node;
+
+        /** @psalm-suppress UndefinedInterfaceMethod */
         $node->getFileInfo()[$key] = $value;
     }
 
@@ -205,7 +210,7 @@ class Util
      * @param mixed $node        File to patch
      * @param mixed $permissions Permissions to set
      */
-    public static function forcePermissions(Node &$node, int $permissions)
+    public static function forcePermissions(Node &$node, int $permissions): void
     {
         self::forceFileInfo($node, 'permissions', $permissions);
     }
@@ -284,7 +289,7 @@ class Util
      *
      * @param $folder Folder to search
      */
-    public static function getAnyMedia(\OCP\Files\Folder $folder): Node
+    public static function getAnyMedia(\OCP\Files\Folder $folder): ?Node
     {
         $query = new SearchQuery(new SearchBinaryOperator(ISearchBinaryOperator::OPERATOR_OR, [
             new SearchComparison(ISearchComparison::COMPARE_LIKE, 'mimetype', 'image/%'),
@@ -338,11 +343,11 @@ class Util
     /**
      * Sanitize a path to keep only ASCII characters and special characters.
      */
-    public static function sanitizePath(string $path): string
+    public static function sanitizePath(string $path): ?string
     {
         $path = str_replace("\0", '', $path); // remove null characters
 
-        return mb_ereg_replace('\/\/+', '/', $path); // remove extra slashes
+        return mb_ereg_replace('\/\/+', '/', $path) ?: null; // remove extra slashes
     }
 
     /**
diff --git a/lib/UtilController.php b/lib/UtilController.php
index eb1b5b15..da4e2838 100644
--- a/lib/UtilController.php
+++ b/lib/UtilController.php
@@ -32,6 +32,7 @@ trait UtilController
      */
     public static function guardExDirect(\Closure $closure): Http\Response
     {
+        /** @psalm-suppress MissingTemplateParam */
         return new class($closure) extends Http\Response implements Http\ICallbackResponse {
             private \Closure $_closure;
 
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 00000000..b166e2bf
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,38 @@
+<?xml version="1.0"?>
+<psalm
+    totallyTyped="true"
+    errorLevel="5"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="lib" />
+        <ignoreFiles>
+            <directory name="tools" />
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+    <extraFiles>
+        <directory name="../../lib" />
+
+        <directory name="../../3rdparty/doctrine" />
+        <directory name="../../3rdparty/psr" />
+        <directory name="../../3rdparty/guzzlehttp" />
+        <directory name="../../3rdparty/doctrine" />
+
+        <directory name="../../apps/files/lib/Event" />
+    </extraFiles>
+    <issueHandlers>
+        <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\Platforms\AbstractPlatform" />
+            </errorLevel>
+        </UndefinedDocblockClass>
+    </issueHandlers>
+</psalm>
\ No newline at end of file