diff --git a/lib/Controller/AlbumsController.php b/lib/Controller/AlbumsController.php
index 6bda003d..bd7acf30 100644
--- a/lib/Controller/AlbumsController.php
+++ b/lib/Controller/AlbumsController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 
@@ -36,8 +37,12 @@ class AlbumsController extends ApiBase
     public function albums(int $t = 0): JSONResponse
     {
         $user = $this->userSession->getUser();
-        if (null === $user || !$this->albumsIsEnabled()) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+        if (null === $user) {
+            return Errors::NotLoggedIn();
+        }
+
+        if (!$this->albumsIsEnabled()) {
+            return Errors::NotEnabled('Albums');
         }
 
         // Run actual query
@@ -73,20 +78,24 @@ class AlbumsController extends ApiBase
     public function download(string $name = ''): JSONResponse
     {
         $user = $this->userSession->getUser();
-        if (null === $user || !$this->albumsIsEnabled()) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+        if (null === $user) {
+            return Errors::NotLoggedIn();
+        }
+
+        if (!$this->albumsIsEnabled()) {
+            return Errors::NotEnabled('Albums');
         }
 
         // Get album
         $album = $this->timelineQuery->getAlbumIfAllowed($user->getUID(), $name);
         if (null === $album) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound("album {$name}");
         }
 
         // Get files
         $files = $this->timelineQuery->getAlbumFiles((int) $album['album_id']);
         if (empty($files)) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound("zero files in album {$name}");
         }
 
         // Get download handle
diff --git a/lib/Controller/ApiBase.php b/lib/Controller/ApiBase.php
index 4d3206b5..360c1088 100644
--- a/lib/Controller/ApiBase.php
+++ b/lib/Controller/ApiBase.php
@@ -26,13 +26,13 @@ namespace OCA\Memories\Controller;
 use OCA\Memories\AppInfo\Application;
 use OCA\Memories\Db\TimelineQuery;
 use OCA\Memories\Db\TimelineRoot;
+use OCA\Memories\Errors;
 use OCA\Memories\Exif;
 use OCA\Memories\Util;
 use OCP\App\IAppManager;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataDisplayResponse;
-use OCP\AppFramework\Http\JSONResponse;
 use OCP\Files\File;
 use OCP\Files\Folder;
 use OCP\Files\IRootFolder;
@@ -358,7 +358,7 @@ class ApiBase extends Controller
             }
         }
 
-        return new JSONResponse([], Http::STATUS_NOT_FOUND);
+        return Errors::NotFound('preview from list');
     }
 
     /**
diff --git a/lib/Controller/ArchiveController.php b/lib/Controller/ArchiveController.php
index 8eb9c791..3d65c551 100644
--- a/lib/Controller/ArchiveController.php
+++ b/lib/Controller/ArchiveController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCA\Memories\Exif;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
@@ -41,7 +42,7 @@ class ArchiveController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse(['message' => 'Not logged in'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
         $uid = $user->getUID();
         $userFolder = $this->rootFolder->getUserFolder($uid);
@@ -49,13 +50,13 @@ class ArchiveController extends ApiBase
         // Check for permissions and get numeric Id
         $file = $userFolder->getById((int) $id);
         if (0 === \count($file)) {
-            return new JSONResponse(['message' => 'No such file'], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound("file id {$id}");
         }
         $file = $file[0];
 
         // Check if user has permissions
         if (!$file->isUpdateable()) {
-            return new JSONResponse(['message' => 'Cannot update this file'], Http::STATUS_FORBIDDEN);
+            return Errors::ForbiddenFileUpdate($file->getName());
         }
 
         // Create archive folder in the root of the user's configured timeline
diff --git a/lib/Controller/DaysController.php b/lib/Controller/DaysController.php
index cedb4910..1cfd31ce 100644
--- a/lib/Controller/DaysController.php
+++ b/lib/Controller/DaysController.php
@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace OCA\Memories\Controller;
 
 use OCA\Memories\Db\TimelineRoot;
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 
@@ -42,7 +43,7 @@ class DaysController extends ApiBase
         try {
             $uid = $this->getUID();
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Get the folder to show
@@ -51,7 +52,7 @@ class DaysController extends ApiBase
         try {
             $root = $this->getRequestRoot();
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_NOT_FOUND);
+            return Errors::Generic($e);
         }
 
         // Run actual query
@@ -120,7 +121,7 @@ class DaysController extends ApiBase
         try {
             $root = $this->getRequestRoot();
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_NOT_FOUND);
+            return Errors::Generic($e);
         }
 
         // Convert to actual dayIds if month view
@@ -166,7 +167,7 @@ class DaysController extends ApiBase
     {
         $id = $this->request->getParam('body_ids');
         if (null === $id) {
-            return new JSONResponse([], Http::STATUS_BAD_REQUEST);
+            return Errors::MissingParameter('body_ids');
         }
 
         return $this->day($id);
diff --git a/lib/Controller/DownloadController.php b/lib/Controller/DownloadController.php
index 4d82bf6e..8add29a1 100644
--- a/lib/Controller/DownloadController.php
+++ b/lib/Controller/DownloadController.php
@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace OCA\Memories\Controller;
 
 use bantu\IniGetWrapper\IniGetWrapper;
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 use OCP\ISession;
@@ -46,7 +47,7 @@ class DownloadController extends ApiBase
         // Get ids from body
         $files = $this->request->getParam('files');
         if (null === $files || !\is_array($files)) {
-            return new JSONResponse([], Http::STATUS_BAD_REQUEST);
+            return Errors::MissingParameter('files');
         }
 
         // Return id
@@ -89,8 +90,9 @@ class DownloadController extends ApiBase
         $session->remove($key);
 
         if (null === $info) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('handle');
         }
+
         $name = $info[0].'-'.date('YmdHis');
         $fileIds = $info[1];
 
@@ -101,7 +103,7 @@ class DownloadController extends ApiBase
 
         // Check if we have any valid ids
         if (0 === \count($fileIds)) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('file IDs');
         }
 
         // Download single file
@@ -124,9 +126,7 @@ class DownloadController extends ApiBase
     {
         $file = $this->getUserFile($fileid);
         if (null === $file) {
-            return new JSONResponse([
-                'message' => 'File not found',
-            ], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($fileid);
         }
 
         // Get the owner's root folder
diff --git a/lib/Controller/ImageController.php b/lib/Controller/ImageController.php
index ee279e78..6e3c7a4b 100644
--- a/lib/Controller/ImageController.php
+++ b/lib/Controller/ImageController.php
@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace OCA\Memories\Controller;
 
 use OCA\Memories\AppInfo\Application;
+use OCA\Memories\Errors;
 use OCA\Memories\Exif;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\FileDisplayResponse;
@@ -49,16 +50,12 @@ class ImageController extends ApiBase
         string $mode = 'fill'
     ) {
         if (-1 === $id || 0 === $x || 0 === $y) {
-            return new JSONResponse([
-                'message' => 'Invalid parameters',
-            ], Http::STATUS_BAD_REQUEST);
+            return Errors::MissingParameter('id, x, y');
         }
 
         $file = $this->getUserFile($id);
         if (!$file) {
-            return new JSONResponse([
-                'message' => 'File not found',
-            ], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($id);
         }
 
         try {
@@ -70,9 +67,9 @@ class ImageController extends ApiBase
 
             return $response;
         } catch (\OCP\Files\NotFoundException $e) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('preview');
         } catch (\InvalidArgumentException $e) {
-            return new JSONResponse([], Http::STATUS_BAD_REQUEST);
+            return Errors::Generic($e);
         }
     }
 
@@ -187,7 +184,7 @@ class ImageController extends ApiBase
     ): JSONResponse {
         $file = $this->getUserFile((int) $id);
         if (!$file) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($id);
         }
 
         // Get the image info
@@ -229,12 +226,12 @@ class ImageController extends ApiBase
     {
         $file = $this->getUserFile((int) $id);
         if (!$file) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($id);
         }
 
         // Check if user has permissions
         if (!$file->isUpdateable()) {
-            return new JSONResponse([], Http::STATUS_FORBIDDEN);
+            return Errors::ForbiddenFileUpdate($file->getName());
         }
 
         // Check for end-to-end encryption
@@ -253,7 +250,7 @@ class ImageController extends ApiBase
         try {
             Exif::setFileExif($file, $raw);
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
+            return Errors::Generic($e);
         }
 
         return new JSONResponse([], Http::STATUS_OK);
@@ -274,13 +271,13 @@ class ImageController extends ApiBase
     {
         $file = $this->getUserFile((int) $id);
         if (!$file) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($id);
         }
 
         // Check if valid image
         $mimetype = $file->getMimeType();
         if (!\in_array($mimetype, Application::IMAGE_MIMES, true)) {
-            return new JSONResponse([], Http::STATUS_FORBIDDEN);
+            return Errors::ForbiddenFileUpdate($file->getName());
         }
 
         /** @var string Blob of image */
diff --git a/lib/Controller/MapController.php b/lib/Controller/MapController.php
index 597f49f9..7c311cee 100644
--- a/lib/Controller/MapController.php
+++ b/lib/Controller/MapController.php
@@ -23,7 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
-use OCP\AppFramework\Http;
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http\JSONResponse;
 
 class MapController extends ApiBase
@@ -39,7 +39,7 @@ class MapController extends ApiBase
         try {
             $root = $this->getRequestRoot();
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Make sure we have bounds and zoom level
@@ -47,7 +47,7 @@ class MapController extends ApiBase
         $bounds = $this->request->getParam('bounds');
         $zoomLevel = $this->request->getParam('zoom');
         if (!$bounds || !$zoomLevel || !is_numeric($zoomLevel)) {
-            return new JSONResponse(['message' => 'Invalid parameters'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::MissingParameter('bounds or zoom');
         }
 
         // A tweakable parameter to determine the number of boxes in the map
@@ -75,7 +75,7 @@ class MapController extends ApiBase
 
             return new JSONResponse($clusters);
         } catch (\Exception $e) {
-            return new JSONResponse(['message' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
+            return Errors::Generic($e);
         }
     }
 }
diff --git a/lib/Controller/OtherController.php b/lib/Controller/OtherController.php
index bee050c6..0e7f8444 100644
--- a/lib/Controller/OtherController.php
+++ b/lib/Controller/OtherController.php
@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace OCA\Memories\Controller;
 
 use OCA\Memories\AppInfo\Application;
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 use OCP\AppFramework\Http\StreamResponse;
@@ -44,7 +45,7 @@ class OtherController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Make sure not running in read-only mode
diff --git a/lib/Controller/PeopleController.php b/lib/Controller/PeopleController.php
index d52a9211..7e729177 100644
--- a/lib/Controller/PeopleController.php
+++ b/lib/Controller/PeopleController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataDisplayResponse;
 use OCP\AppFramework\Http\DataResponse;
@@ -40,18 +41,18 @@ class PeopleController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check faces enabled for this user
         if (!$this->recognizeIsEnabled()) {
-            return new JSONResponse(['message' => 'Recognize app not enabled or not v3+.'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Recognize');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
@@ -75,25 +76,25 @@ class PeopleController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new DataResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check faces enabled for this user
         if (!$this->recognizeIsEnabled()) {
-            return new DataResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Recognize');
         }
 
         // Get folder to search for
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
         $detections = $this->timelineQuery->getPeopleRecognizePreview($root, $id);
 
         if (null === $detections || 0 === \count($detections)) {
-            return new DataResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('detections');
         }
 
         return $this->getPreviewResponse($detections, $user, 1.5);
@@ -108,18 +109,18 @@ class PeopleController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check if face recognition is installed and enabled for this user
         if (!$this->facerecognitionIsInstalled()) {
-            return new DataResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Face Recognition');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // If the user has recognition disabled, just returns an empty response.
@@ -155,18 +156,18 @@ class PeopleController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new DataResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check if face recognition is installed and enabled for this user
         if (!$this->facerecognitionIsInstalled()) {
-            return new DataResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Face Recognition');
         }
 
         // Get folder to search for
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // If the user has facerecognition disabled, just returns an empty response.
@@ -179,7 +180,7 @@ class PeopleController extends ApiBase
         $detections = $this->timelineQuery->getFaceRecognitionPreview($root, $currentModel, $id);
 
         if (null === $detections || 0 === \count($detections)) {
-            return new DataResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('detections');
         }
 
         return $this->getPreviewResponse($detections, $user, 1.8);
@@ -242,7 +243,7 @@ class PeopleController extends ApiBase
 
         // Make sure the preview is valid
         if (null === $image) {
-            return new DataResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('preview');
         }
 
         // Set quality and make progressive
diff --git a/lib/Controller/PlacesController.php b/lib/Controller/PlacesController.php
index 46174f0f..44ddd4f4 100644
--- a/lib/Controller/PlacesController.php
+++ b/lib/Controller/PlacesController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 
@@ -37,18 +38,18 @@ class PlacesController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check tags enabled for this user
         if (!$this->placesIsEnabled()) {
-            return new JSONResponse(['message' => 'Places not enabled'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('places');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
@@ -68,24 +69,24 @@ class PlacesController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check tags enabled for this user
         if (!$this->placesIsEnabled()) {
-            return new JSONResponse(['message' => 'Places not enabled'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('places');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
         $list = $this->timelineQuery->getPlacePreviews($id, $root);
         if (null === $list || 0 === \count($list)) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('previews');
         }
         shuffle($list);
 
diff --git a/lib/Controller/ShareController.php b/lib/Controller/ShareController.php
index 0d51e6ed..74c86bfe 100644
--- a/lib/Controller/ShareController.php
+++ b/lib/Controller/ShareController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 
@@ -40,9 +41,7 @@ class ShareController extends ApiBase
     {
         $file = $this->getNodeByIdOrPath($id, $path);
         if (!$file) {
-            return new JSONResponse([
-                'message' => 'File not found',
-            ], Http::STATUS_FORBIDDEN);
+            return Errors::Forbidden('file');
         }
 
         /** @var \OCP\Share\IManager $shareManager */
@@ -50,9 +49,7 @@ class ShareController extends ApiBase
 
         $shares = $shareManager->getSharesBy($this->getUID(), \OCP\Share\IShare::TYPE_LINK, $file, true, 50, 0);
         if (empty($shares)) {
-            return new JSONResponse([
-                'message' => 'No external links found',
-            ], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('external links');
         }
 
         $links = array_map([$this, 'makeShareResponse'], $shares);
@@ -72,9 +69,7 @@ class ShareController extends ApiBase
     {
         $file = $this->getNodeByIdOrPath($id, $path);
         if (!$file) {
-            return new JSONResponse([
-                'message' => 'You are not allowed to share this file',
-            ], Http::STATUS_FORBIDDEN);
+            return Errors::Forbidden('You are not allowed to share this file');
         }
 
         /** @var \OCP\Share\IManager $shareManager */
@@ -101,9 +96,7 @@ class ShareController extends ApiBase
     {
         $uid = $this->getUID();
         if (!$uid) {
-            return new JSONResponse([
-                'message' => 'You are not logged in',
-            ], Http::STATUS_FORBIDDEN);
+            return Errors::NotLoggedIn();
         }
 
         /** @var \OCP\Share\IManager $shareManager */
@@ -112,9 +105,7 @@ class ShareController extends ApiBase
         $share = $shareManager->getShareById($id);
 
         if ($share->getSharedBy() !== $uid) {
-            return new JSONResponse([
-                'message' => 'You are not the owner of this share',
-            ], Http::STATUS_FORBIDDEN);
+            return Errors::Forbidden('You are not the owner of this share');
         }
 
         $shareManager->deleteShare($share);
diff --git a/lib/Controller/TagsController.php b/lib/Controller/TagsController.php
index ad244384..a847e3e3 100644
--- a/lib/Controller/TagsController.php
+++ b/lib/Controller/TagsController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 
@@ -37,18 +38,18 @@ class TagsController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check tags enabled for this user
         if (!$this->tagsIsEnabled()) {
-            return new JSONResponse(['message' => 'Tags not enabled for user'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Tags');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
@@ -70,18 +71,18 @@ class TagsController extends ApiBase
     {
         $user = $this->userSession->getUser();
         if (null === $user) {
-            return new JSONResponse([], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotLoggedIn();
         }
 
         // Check tags enabled for this user
         if (!$this->tagsIsEnabled()) {
-            return new JSONResponse(['message' => 'Tags not enabled for user'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Tags');
         }
 
         // If this isn't the timeline folder then things aren't going to work
         $root = $this->getRequestRoot();
         if ($root->isEmpty()) {
-            return new JSONResponse([], Http::STATUS_NOT_FOUND);
+            return Errors::NoRequestRoot();
         }
 
         // Run actual query
@@ -106,20 +107,18 @@ class TagsController extends ApiBase
     {
         // Check tags enabled for this user
         if (!$this->tagsIsEnabled()) {
-            return new JSONResponse(['message' => 'Tags not enabled for user'], Http::STATUS_PRECONDITION_FAILED);
+            return Errors::NotEnabled('Tags');
         }
 
         // Check the user is allowed to edit the file
         $file = $this->getUserFile($id);
         if (null === $file) {
-            return new JSONResponse([
-                'message' => 'File not found',
-            ], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($id);
         }
 
         // Check the user is allowed to edit the file
         if (!$file->isUpdateable() || !($file->getPermissions() & \OCP\Constants::PERMISSION_UPDATE)) {
-            return new JSONResponse(['message' => 'Cannot update this file'], Http::STATUS_FORBIDDEN);
+            return Errors::ForbiddenFileUpdate($file->getName());
         }
 
         // Get mapper from tags to objects
diff --git a/lib/Controller/VideoController.php b/lib/Controller/VideoController.php
index 44872962..01a08d13 100644
--- a/lib/Controller/VideoController.php
+++ b/lib/Controller/VideoController.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Controller;
 
+use OCA\Memories\Errors;
 use OCA\Memories\Exif;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataDisplayResponse;
@@ -44,39 +45,35 @@ class VideoController extends ApiBase
     {
         // Make sure not running in read-only mode
         if (false !== $this->config->getSystemValue('memories.vod.disable', 'UNSET')) {
-            return new JSONResponse(['message' => 'Transcoding disabled'], Http::STATUS_FORBIDDEN);
+            return Errors::Forbidden('Transcoding disabled');
         }
 
         // Check client identifier is 8 characters or more
         if (\strlen($client) < 8) {
-            return new JSONResponse(['message' => 'Invalid client identifier'], Http::STATUS_BAD_REQUEST);
+            return Errors::MissingParameter('client (invalid)');
         }
 
         // Get file
         $file = $this->getUserFile($fileid);
-        if (!$file) {
-            return new JSONResponse(['message' => 'File not found'], Http::STATUS_NOT_FOUND);
-        }
-
-        if (!$file->isReadable()) {
-            return new JSONResponse(['message' => 'File not readable'], Http::STATUS_FORBIDDEN);
+        if (!$file || !$file->isReadable()) {
+            return Errors::NotFoundFile($fileid);
         }
 
         // Local files only for now
         if (!$file->getStorage()->isLocal()) {
-            return new JSONResponse(['message' => 'External storage not supported'], Http::STATUS_FORBIDDEN);
+            return Errors::Forbidden('External storage not supported');
         }
 
         // Get file path
         $path = $file->getStorage()->getLocalFile($file->getInternalPath());
         if (!$path || !file_exists($path)) {
-            return new JSONResponse(['message' => 'File not found'], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('local file path');
         }
 
         // Check if file starts with temp dir
         $tmpDir = sys_get_temp_dir();
         if (0 === strpos($path, $tmpDir)) {
-            return new JSONResponse(['message' => 'File is in temp dir!'], Http::STATUS_NOT_FOUND);
+            return Errors::Forbidden('files in temp directory not supported');
         }
 
         // Request and check data was received
@@ -93,7 +90,7 @@ class VideoController extends ApiBase
             $msg = 'Transcode failed: '.$e->getMessage();
             $this->logger->error($msg, ['app' => 'memories']);
 
-            return new JSONResponse(['message' => $msg], Http::STATUS_INTERNAL_SERVER_ERROR);
+            return Errors::Generic($e);
         }
 
         // The response was already streamed, so we have nothing to do here
@@ -117,12 +114,12 @@ class VideoController extends ApiBase
     ) {
         $file = $this->getUserFile($fileid);
         if (null === $file) {
-            return new JSONResponse(['message' => 'File not found'], Http::STATUS_NOT_FOUND);
+            return Errors::NotFoundFile($fileid);
         }
 
         // Check file liveid
         if (!$liveid) {
-            return new JSONResponse(['message' => 'Live ID not provided'], Http::STATUS_BAD_REQUEST);
+            return Errors::MissingParameter('liveid');
         }
 
         // Response data
@@ -144,13 +141,13 @@ class VideoController extends ApiBase
             try { // Get trailer
                 $blob = Exif::getBinaryExifProp($path, '-trailer');
             } catch (\Exception $e) {
-                return new JSONResponse(['message' => 'Trailer not found'], Http::STATUS_NOT_FOUND);
+                return Errors::NotFound('file trailer');
             }
         } elseif ('self__embeddedvideo' === $liveid) {
             try { // Get embedded video file
                 $blob = Exif::getBinaryExifProp($path, '-EmbeddedVideoFile');
             } catch (\Exception $e) {
-                return new JSONResponse(['message' => 'Embedded video not found'], Http::STATUS_NOT_FOUND);
+                return Errors::NotFound('embedded video');
             }
         } elseif (str_starts_with($liveid, 'self__traileroffset=')) {
             // Remove prefix
@@ -165,14 +162,14 @@ class VideoController extends ApiBase
             // Get stored video file (Apple MOV)
             $lp = $this->timelineQuery->getLivePhoto($fileid);
             if (!$lp || $lp['liveid'] !== $liveid) {
-                return new JSONResponse(['message' => 'Live ID not found'], Http::STATUS_NOT_FOUND);
+                return Errors::NotFound('live video entry');
             }
 
             // Get and return file
             $liveFileId = (int) $lp['fileid'];
             $files = $this->rootFolder->getById($liveFileId);
             if (0 === \count($files)) {
-                return new JSONResponse(['message' => 'Live file not found'], Http::STATUS_NOT_FOUND);
+                return Errors::NotFound('live video file');
             }
             $liveFile = $files[0];
 
@@ -191,7 +188,7 @@ class VideoController extends ApiBase
 
         // Data not found
         if (!$blob) {
-            return new JSONResponse(['message' => 'Live file not found'], Http::STATUS_NOT_FOUND);
+            return Errors::NotFound('live video data');
         }
 
         // Transcode video if allowed
diff --git a/lib/Errors.php b/lib/Errors.php
new file mode 100644
index 00000000..7ff23783
--- /dev/null
+++ b/lib/Errors.php
@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\Memories;
+
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\DataResponse;
+
+class Errors
+{
+    public static function Generic(\Exception $e, int $status = Http::STATUS_INTERNAL_SERVER_ERROR): Http\Response
+    {
+        return new DataResponse([
+            'message' => $e->getMessage(),
+        ], $status);
+    }
+
+    public static function NotLoggedIn(): Http\Response
+    {
+        return new DataResponse([
+            'message' => 'User not logged in',
+        ], Http::STATUS_PRECONDITION_FAILED);
+    }
+
+    public static function NotEnabled(string $app): Http\Response
+    {
+        return new DataResponse([
+            'message' => "{$app} app not enabled or not v3+.",
+        ], Http::STATUS_PRECONDITION_FAILED);
+    }
+
+    public static function NoRequestRoot(): Http\Response
+    {
+        return new DataResponse([
+            'message' => 'Request root could not be determined',
+        ], Http::STATUS_NOT_FOUND);
+    }
+
+    public static function NotFound(string $ctx): Http\Response
+    {
+        return new DataResponse([
+            'message' => "Not found ({$ctx})",
+        ], Http::STATUS_NOT_FOUND);
+    }
+
+    public static function NotFoundFile($identifier): Http\Response
+    {
+        return new DataResponse([
+            'message' => "File not found ({$identifier})",
+        ], Http::STATUS_NOT_FOUND);
+    }
+
+    public static function Forbidden(string $ctx): Http\Response
+    {
+        return new DataResponse([
+            'message' => "Forbidden ({$ctx})",
+        ], Http::STATUS_FORBIDDEN);
+    }
+
+    public static function ForbiddenFileUpdate(string $name): Http\Response
+    {
+        return new DataResponse([
+            'message' => "Forbidden ({$name} cannot be updated)",
+        ], Http::STATUS_FORBIDDEN);
+    }
+
+    public static function MissingParameter(string $name): Http\Response
+    {
+        return new DataResponse([
+            'message' => "Missing parameter ({$name})",
+        ], Http::STATUS_BAD_REQUEST);
+    }
+}