diff --git a/src/.env.example b/src/.env.example
--- a/src/.env.example
+++ b/src/.env.example
@@ -108,6 +108,7 @@
 REDIS_PORT=6379
 
 OCTANE_HTTP_HOST=127.0.0.1
+SWOOLE_PACKAGE_MAX_LENGTH=10485760
 
 PAYMENT_PROVIDER=
 MOLLIE_KEY=
diff --git a/src/app/Backends/Storage.php b/src/app/Backends/Storage.php
new file mode 100644
--- /dev/null
+++ b/src/app/Backends/Storage.php
@@ -0,0 +1,268 @@
+<?php
+
+namespace App\Backends;
+
+use App\Fs\Chunk;
+use App\Fs\Item;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\Storage as LaravelStorage;
+use Illuminate\Support\Str;
+use Symfony\Component\HttpFoundation\StreamedResponse;
+
+class Storage
+{
+    /** @const How long the resumable upload "token" is valid (in seconds) */
+    public const UPLOAD_TTL = 60 * 60 * 6;
+
+
+    /**
+     * Delete a file.
+     *
+     * @param \App\Fs\Item $file File object
+     *
+     * @throws \Exception
+     */
+    public static function fileDelete(Item $file): void
+    {
+        $disk = LaravelStorage::disk('files');
+
+        $path = $file->path . '/' . $file->id;
+
+        // TODO: Deleting files might be slow, consider marking as deleted and async job
+
+        $disk->deleteDirectory($path);
+
+        $file->chunks()->delete();
+    }
+
+    /**
+     * File download handler.
+     *
+     * @param \App\Fs\Item $file File object
+     *
+     * @throws \Exception
+     */
+    public static function fileDownload(Item $file): StreamedResponse
+    {
+        $response = new StreamedResponse();
+
+        $props = $file->getProperties(['name', 'size', 'mimetype']);
+
+        // Prepare the file name for the Content-Disposition header
+        $extension = pathinfo($props['name'], \PATHINFO_EXTENSION) ?: 'file';
+        $fallbackName = str_replace('%', '', Str::ascii($props['name'])) ?: "file.{$extension}";
+        $disposition = $response->headers->makeDisposition('attachment', $props['name'], $fallbackName);
+
+        $response->headers->replace([
+                'Content-Length' => $props['size'] ?: 0,
+                'Content-Type' => $props['mimetype'],
+                'Content-Disposition' => $disposition,
+        ]);
+
+        $response->setCallback(function () use ($file) {
+            $file->chunks()->orderBy('sequence')->get()->each(function ($chunk) use ($file) {
+                $disk = LaravelStorage::disk('files');
+                $path = Storage::chunkLocation($chunk->chunk_id, $file);
+
+                $stream = $disk->readStream($path);
+
+                fpassthru($stream);
+                fclose($stream);
+            });
+        });
+
+        return $response;
+    }
+
+    /**
+     * File upload handler
+     *
+     * @param resource      $stream File input stream
+     * @param array         $params Request parameters
+     * @param ?\App\Fs\Item $file   The file object
+     *
+     * @return array File/Response attributes
+     * @throws \Exception
+     */
+    public static function fileInput($stream, array $params, Item $file = null): array
+    {
+        if (!empty($params['uploadId'])) {
+            return self::fileInputResumable($stream, $params, $file);
+        }
+
+        $disk = LaravelStorage::disk('files');
+
+        $chunkId = \App\Utils::uuidStr();
+
+        $path = self::chunkLocation($chunkId, $file);
+
+        $disk->writeStream($path, $stream);
+
+        $fileSize = $disk->fileSize($path);
+
+        // Update the file type and size information
+        $file->setProperties([
+                'size' => $fileSize,
+                'mimetype' => self::mimetype($path),
+        ]);
+
+        // Assign the node to the file, "unlink" any old nodes of this file
+        $file->chunks()->delete();
+        $file->chunks()->create([
+                'chunk_id' => $chunkId,
+                'sequence' => 0,
+                'size' => $fileSize,
+        ]);
+
+        return ['id' => $file->id];
+    }
+
+    /**
+     * Resumable file upload handler
+     *
+     * @param resource      $stream File input stream
+     * @param array         $params Request parameters
+     * @param ?\App\Fs\Item $file   The file object
+     *
+     * @return array File/Response attributes
+     * @throws \Exception
+     */
+    protected static function fileInputResumable($stream, array $params, Item $file = null): array
+    {
+        // Initial request, save file metadata, return uploadId
+        if ($params['uploadId'] == 'resumable') {
+            if (empty($params['size']) || empty($file)) {
+                throw new \Exception("Missing parameters of resumable file upload.");
+            }
+
+            $params['uploadId'] = \App\Utils::uuidStr();
+
+            $upload = [
+                'fileId' => $file->id,
+                'size' => $params['size'],
+                'uploaded' => 0,
+            ];
+
+            if (!Cache::add('upload:' . $params['uploadId'], $upload, self::UPLOAD_TTL)) {
+                throw new \Exception("Failed to create cache entry for resumable file upload.");
+            }
+
+            return [
+                'uploadId' => $params['uploadId'],
+                'uploaded' => 0,
+                'maxChunkSize' => (\config('octane.swoole.options.package_max_length') ?: 10 * 1024 * 1024) - 8192,
+            ];
+        }
+
+        $upload = Cache::get('upload:' . $params['uploadId']);
+
+        if (empty($upload)) {
+            throw new \Exception("Cache entry for resumable file upload does not exist.");
+        }
+
+        $file = Item::find($upload['fileId']);
+
+        if (!$file) {
+            throw new \Exception("Invalid fileId for resumable file upload.");
+        }
+
+        $from = $params['from'] ?? 0;
+
+        // Sanity checks on the input parameters
+        // TODO: Support uploading again a chunk that already has been uploaded?
+        if ($from < $upload['uploaded'] || $from > $upload['uploaded'] || $from > $upload['size']) {
+            throw new \Exception("Invalid 'from' parameter for resumable file upload.");
+        }
+
+        $disk = LaravelStorage::disk('files');
+
+        $chunkId = \App\Utils::uuidStr();
+
+        $path = self::chunkLocation($chunkId, $file);
+
+        // Save the file chunk
+        $disk->writeStream($path, $stream);
+
+        // Detect file type using the first chunk
+        if ($from == 0) {
+            $upload['mimetype'] = self::mimetype($path);
+            $upload['chunks'] = [];
+        }
+
+        $chunkSize = $disk->fileSize($path);
+
+        // Create the chunk record
+        $file->chunks()->create([
+                'chunk_id' => $chunkId,
+                'sequence' => count($upload['chunks']),
+                'size' => $chunkSize,
+                'deleted_at' => \now(), // not yet active chunk
+        ]);
+
+        $upload['chunks'][] = $chunkId;
+        $upload['uploaded'] += $chunkSize;
+
+        // Update the file metadata after the upload of all chunks is completed
+        if ($upload['uploaded'] >= $upload['size']) {
+            // Update file metadata
+            $file->setProperties([
+                    'size' => $upload['uploaded'],
+                    'mimetype' => $upload['mimetype'] ?: 'application/octet-stream',
+            ]);
+
+            // Assign uploaded chunks to the file, "unlink" any old chunks of this file
+            $file->chunks()->delete();
+            $file->chunks()->whereIn('chunk_id', $upload['chunks'])->restore();
+
+            // TODO: Create a "cron" job to remove orphaned nodes from DB and the storage.
+            // I.e. all with deleted_at set and older than UPLOAD_TTL
+
+            // Delete the upload cache record
+            Cache::forget('upload:' . $params['uploadId']);
+
+            return ['id' => $file->id];
+        }
+
+        // Update the upload metadata
+        Cache::put('upload:' . $params['uploadId'], $upload, self::UPLOAD_TTL);
+
+        return ['uploadId' => $params['uploadId'], 'uploaded' => $upload['uploaded']];
+    }
+
+    /**
+     * Get the file mime type.
+     *
+     * @param string $path File location
+     *
+     * @return string File mime type
+     */
+    protected static function mimetype(string $path): string
+    {
+        $disk = LaravelStorage::disk('files');
+
+        // TODO: If file is empty, detect the mimetype based on the extension?
+        try {
+            return $disk->mimeType($path);
+        } catch (\Exception $e) {
+            // do nothing
+        }
+
+        // TODO: If it fails detect the mimetype based on extension?
+
+        return 'application/octet-stream';
+    }
+
+    /**
+     * Node location in the storage
+     *
+     * @param string        $chunkId Chunk identifier
+     * @param \App\Fs\Item  $file    File the chunk belongs to
+     *
+     * @return string Chunk location
+     */
+    public static function chunkLocation(string $chunkId, Item $file): string
+    {
+        return $file->path . '/' . $file->id . '/' . $chunkId;
+    }
+}
diff --git a/src/app/Fs/Chunk.php b/src/app/Fs/Chunk.php
new file mode 100644
--- /dev/null
+++ b/src/app/Fs/Chunk.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace App\Fs;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+/**
+ * The eloquent definition of a file chunk.
+ *
+ * @property int     $id        Chunk identifier
+ * @property string  $chunk_id  Chunk long identifier (storage file name)
+ * @property string  $item_id   Item identifier
+ * @property int     $sequence  Chunk sequence number
+ * @property int     $size      Chunk size
+ */
+class Chunk extends Model
+{
+    use SoftDeletes;
+
+    /** @var array<int, string> The attributes that are mass assignable */
+    protected $fillable = ['item_id', 'chunk_id', 'sequence', 'deleted_at', 'size'];
+
+    /** @var string Database table name */
+    protected $table = 'fs_chunks';
+
+
+    /**
+     * The item (file) the chunk belongs to.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function item()
+    {
+        return $this->belongsTo(Item::class);
+    }
+}
diff --git a/src/app/Fs/Item.php b/src/app/Fs/Item.php
new file mode 100644
--- /dev/null
+++ b/src/app/Fs/Item.php
@@ -0,0 +1,178 @@
+<?php
+
+namespace App\Fs;
+
+use App\User;
+use App\Traits\UuidStrKeyTrait;
+use Illuminate\Database\Eloquent\Casts\Attribute;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+/**
+ * The eloquent definition of a filesystem item.
+ *
+ * @property string $id        Item identifier
+ * @property int    $type      Item type
+ * @property string $path      Item path (readonly)
+ * @property int    $user_id   Item owner
+ */
+class Item extends Model
+{
+    use SoftDeletes;
+    use UuidStrKeyTrait;
+
+    public const TYPE_INCOMPLETE = 0;
+    public const TYPE_FILE       = 1;
+    public const TYPE_FOLDER     = 2;
+
+    /** @var array<int, string> The attributes that are mass assignable */
+    protected $fillable = ['user_id', 'type'];
+
+    /** @var array<string, string> The attributes that should be cast */
+    protected $casts = [
+        'created_at' => 'datetime:Y-m-d H:i:s',
+        'updated_at' => 'datetime:Y-m-d H:i:s',
+    ];
+
+    /** @var string Database table name */
+    protected $table = 'fs_items';
+
+
+    /**
+     * COntent chunks of this item (file).
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function chunks()
+    {
+        return $this->hasMany(Chunk::class);
+    }
+
+    /**
+     * Getter for the file path (without the filename) in the storage.
+     *
+     * @return \Illuminate\Database\Eloquent\Casts\Attribute
+     */
+    protected function path(): Attribute
+    {
+        return Attribute::make(
+            get: function ($value) {
+                if (empty($this->id)) {
+                    throw new \Exception("Cannot get path for an item without ID");
+                }
+
+                $id = substr($this->id, 0, 6);
+
+                return implode('/', str_split($id, 2));
+            }
+        );
+    }
+
+    /**
+     * Any (additional) properties of this item.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function properties()
+    {
+        return $this->hasMany(Property::class);
+    }
+
+    /**
+     * Obtain the value for an item property
+     *
+     * @param string $key     Property name
+     * @param mixed  $default Default value, to be used if not found
+     *
+     * @return string|null Property value
+     */
+    public function getProperty(string $key, $default = null)
+    {
+        $attr = $this->properties()->where('key', $key)->first();
+
+        return $attr ? $attr->value : $default;
+    }
+
+    /**
+     * Obtain the values for many properties in one go (for better performance).
+     *
+     * @param array $keys Property names
+     *
+     * @return array Property key=value hash, includes also requested but non-existing properties
+     */
+    public function getProperties(array $keys): array
+    {
+        $props = array_fill_keys($keys, null);
+
+        $this->properties()->whereIn('key', $keys)->get()
+            ->each(function ($prop) use (&$props) {
+                $props[$prop->key] = $prop->value;
+            });
+
+        return $props;
+    }
+
+    /**
+     * Remove a property
+     *
+     * @param string $key Property name
+     */
+    public function removeProperty(string $key): void
+    {
+        $this->setProperty($key, null);
+    }
+
+    /**
+     * Create or update a property.
+     *
+     * @param string      $key   Property name
+     * @param string|null $value The new value for the property
+     */
+    public function setProperty(string $key, $value): void
+    {
+        $this->storeProperty($key, $value);
+    }
+
+    /**
+     * Create or update multiple properties in one fell swoop.
+     *
+     * @param array $data An associative array of key value pairs.
+     */
+    public function setProperties(array $data = []): void
+    {
+        foreach ($data as $key => $value) {
+            $this->storeProperty($key, $value);
+        }
+    }
+
+    /**
+     * Create or update a property.
+     *
+     * @param string      $key   Property name
+     * @param string|null $value The new value for the property
+     */
+    private function storeProperty(string $key, $value): void
+    {
+        if ($value === null || $value === '') {
+            // Note: We're selecting the record first, so observers can act
+            if ($prop = $this->properties()->where('key', $key)->first()) {
+                $prop->delete();
+            }
+        } else {
+            $this->properties()->updateOrCreate(
+                ['key' => $key],
+                ['value' => $value]
+            );
+        }
+    }
+
+    /**
+     * The user to which this item belongs.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function user()
+    {
+        return $this->belongsTo(User::class, 'user_id', 'id');
+    }
+}
diff --git a/src/app/Fs/Property.php b/src/app/Fs/Property.php
new file mode 100644
--- /dev/null
+++ b/src/app/Fs/Property.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Fs;
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * A collection of properties for a filesystem item.
+ *
+ * @property int    $id       Property identifier
+ * @property int    $item_id  Item identifier
+ * @property string $key      Attribute name
+ * @property string $value    Attrbute value
+ */
+class Property extends Model
+{
+    /** @var array<int, string> The attributes that are mass assignable */
+    protected $fillable = ['item_id', 'key', 'value'];
+
+    /** @var string Database table name */
+    protected $table = 'fs_properties';
+
+
+    /**
+     * The item to which this property belongs.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function item()
+    {
+        return $this->belongsTo(Item::class);
+    }
+}
diff --git a/src/app/Handlers/Beta/Base.php b/src/app/Handlers/Beta/Base.php
--- a/src/app/Handlers/Beta/Base.php
+++ b/src/app/Handlers/Beta/Base.php
@@ -4,6 +4,16 @@
 
 class Base extends \App\Handlers\Base
 {
+    /**
+     * The entitleable class for this handler.
+     *
+     * @return string
+     */
+    public static function entitleableClass(): string
+    {
+        return \App\User::class;
+    }
+
     /**
      * Check if the SKU is available to the user/domain.
      *
@@ -67,4 +77,15 @@
 
         return true;
     }
+
+    /**
+     * The priority that specifies the order of SKUs in UI.
+     * Higher number means higher on the list.
+     *
+     * @return int
+     */
+    public static function priority(): int
+    {
+        return 10;
+    }
 }
diff --git a/src/app/Handlers/Beta/Distlists.php b/src/app/Handlers/Beta/Distlists.php
--- a/src/app/Handlers/Beta/Distlists.php
+++ b/src/app/Handlers/Beta/Distlists.php
@@ -4,16 +4,6 @@
 
 class Distlists extends Base
 {
-    /**
-     * The entitleable class for this handler.
-     *
-     * @return string
-     */
-    public static function entitleableClass(): string
-    {
-        return \App\User::class;
-    }
-
     /**
      * Check if the SKU is available to the user/domain.
      *
@@ -35,15 +25,4 @@
 
         return false;
     }
-
-    /**
-     * The priority that specifies the order of SKUs in UI.
-     * Higher number means higher on the list.
-     *
-     * @return int
-     */
-    public static function priority(): int
-    {
-        return 10;
-    }
 }
diff --git a/src/app/Handlers/Beta/Resources.php b/src/app/Handlers/Beta/Resources.php
--- a/src/app/Handlers/Beta/Resources.php
+++ b/src/app/Handlers/Beta/Resources.php
@@ -4,16 +4,6 @@
 
 class Resources extends Base
 {
-    /**
-     * The entitleable class for this handler.
-     *
-     * @return string
-     */
-    public static function entitleableClass(): string
-    {
-        return \App\User::class;
-    }
-
     /**
      * Check if the SKU is available to the user/domain.
      *
@@ -35,15 +25,4 @@
 
         return false;
     }
-
-    /**
-     * The priority that specifies the order of SKUs in UI.
-     * Higher number means higher on the list.
-     *
-     * @return int
-     */
-    public static function priority(): int
-    {
-        return 10;
-    }
 }
diff --git a/src/app/Handlers/Beta/SharedFolders.php b/src/app/Handlers/Beta/SharedFolders.php
--- a/src/app/Handlers/Beta/SharedFolders.php
+++ b/src/app/Handlers/Beta/SharedFolders.php
@@ -4,16 +4,6 @@
 
 class SharedFolders extends Base
 {
-    /**
-     * The entitleable class for this handler.
-     *
-     * @return string
-     */
-    public static function entitleableClass(): string
-    {
-        return \App\User::class;
-    }
-
     /**
      * Check if the SKU is available to the user/domain.
      *
@@ -35,15 +25,4 @@
 
         return false;
     }
-
-    /**
-     * The priority that specifies the order of SKUs in UI.
-     * Higher number means higher on the list.
-     *
-     * @return int
-     */
-    public static function priority(): int
-    {
-        return 10;
-    }
 }
diff --git a/src/app/Handlers/Files.php b/src/app/Handlers/Files.php
new file mode 100644
--- /dev/null
+++ b/src/app/Handlers/Files.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace App\Handlers;
+
+class Files extends Beta\Base
+{
+}
diff --git a/src/app/Http/Controllers/API/V4/FilesController.php b/src/app/Http/Controllers/API/V4/FilesController.php
new file mode 100644
--- /dev/null
+++ b/src/app/Http/Controllers/API/V4/FilesController.php
@@ -0,0 +1,611 @@
+<?php
+
+namespace App\Http\Controllers\API\V4;
+
+use App\Backends\Storage;
+use App\Fs\Item;
+use App\Fs\Property;
+use App\Http\Controllers\RelationController;
+use App\Rules\FileName;
+use App\User;
+use App\Utils;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\Validator;
+
+class FilesController extends RelationController
+{
+    protected const READ = 'r';
+    protected const WRITE = 'w';
+
+    /** @var string Resource localization label */
+    protected $label = 'file';
+
+    /** @var string Resource model name */
+    protected $model = Item::class;
+
+
+    /**
+     * Delete a file.
+     *
+     * @param string $id File identifier
+     *
+     * @return \Illuminate\Http\JsonResponse The response
+     */
+    public function destroy($id)
+    {
+        // Only the file owner can do that, for now
+        $file = $this->inputFile($id, null);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        // FIXME: Here we're just deleting the file, but maybe it would be better/faster
+        // to mark the file (record in db) as deleted and invoke a job to
+        // delete it asynchronously?
+
+        Storage::fileDelete($file);
+
+        $file->delete();
+
+        return response()->json([
+                'status' => 'success',
+                'message' => \trans('app.file-delete-success'),
+        ]);
+    }
+
+    /**
+     * Fetch content of a file.
+     *
+     * @param string $id The download (not file) identifier.
+     *
+     * @return \Illuminate\Http\Response|\Symfony\Component\HttpFoundation\StreamedResponse
+     */
+    public function download($id)
+    {
+        $fileId = Cache::get('download:' . $id);
+
+        if (!$fileId) {
+            return response('Not found', 404);
+        }
+
+        $file = Item::find($fileId);
+
+        if (!$file) {
+            return response('Not found', 404);
+        }
+
+        return Storage::fileDownload($file);
+    }
+
+    /**
+     * Fetch the permissions for the specific file.
+     *
+     * @param string $fileId The file identifier.
+     *
+     * @return \Illuminate\Http\JsonResponse
+     */
+    public function getPermissions($fileId)
+    {
+        // Only the file owner can do that, for now
+        $file = $this->inputFile($fileId, null);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        $result = $file->properties()->where('key', 'like', 'share-%')->get()->map(
+            fn($prop) => self::permissionToClient($prop->key, $prop->value)
+        );
+
+        $result = [
+            'list' => $result,
+            'count' => count($result),
+        ];
+
+        return response()->json($result);
+    }
+
+    /**
+     * Add permission for the specific file.
+     *
+     * @param string $fileId The file identifier.
+     *
+     * @return \Illuminate\Http\JsonResponse
+     */
+    public function createPermission($fileId)
+    {
+        // Only the file owner can do that, for now
+        $file = $this->inputFile($fileId, null);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        // Validate/format input
+        $v = Validator::make(request()->all(), [
+                'user' => 'email|required',
+                'permissions' => 'string|required',
+        ]);
+
+        $errors = $v->fails() ? $v->errors()->toArray() : [];
+
+        $acl = self::inputAcl(request()->input('permissions'));
+
+        if (empty($errors['permissions']) && empty($acl)) {
+            $errors['permissions'] = \trans('validation.file-perm-invalid');
+        }
+
+        $user = \strtolower(request()->input('user'));
+
+        // Check if it already exists
+        if (empty($errors['user'])) {
+            if ($file->properties()->where('key', 'like', 'share-%')->where('value', 'like', "$user:%")->exists()) {
+                $errors['user'] = \trans('validation.file-perm-exists');
+            }
+        }
+
+        if (!empty($errors)) {
+            return response()->json(['status' => 'error', 'errors' => $errors], 422);
+        }
+
+        // Create the property (with a unique id)
+        while ($shareId = 'share-' . \App\Utils::uuidStr()) {
+            if (!Property::where('key', $shareId)->exists()) {
+                break;
+            }
+        }
+
+        $file->setProperty($shareId, "$user:$acl");
+
+        $result = self::permissionToClient($shareId, "$user:$acl");
+
+        return response()->json($result + [
+                'status' => 'success',
+                'message' => \trans('app.file-permissions-create-success'),
+        ]);
+    }
+
+    /**
+     * Delete file permission.
+     *
+     * @param string $fileId The file identifier.
+     * @param string $id     The file permission identifier.
+     *
+     * @return \Illuminate\Http\JsonResponse
+     */
+    public function deletePermission($fileId, $id)
+    {
+        // Only the file owner can do that, for now
+        $file = $this->inputFile($fileId, null);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        $property = $file->properties()->where('key', $id)->first();
+
+        if (!$property) {
+            return $this->errorResponse(404);
+        }
+
+        $property->delete();
+
+        return response()->json([
+                'status' => 'success',
+                'message' => \trans('app.file-permissions-delete-success'),
+        ]);
+    }
+
+    /**
+     * Update file permission.
+     *
+     * @param \Illuminate\Http\Request $request The API request.
+     * @param string                   $fileId  The file identifier.
+     * @param string                   $id      The file permission identifier.
+     *
+     * @return \Illuminate\Http\JsonResponse
+     */
+    public function updatePermission(Request $request, $fileId, $id)
+    {
+        // Only the file owner can do that, for now
+        $file = $this->inputFile($fileId, null);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        $property = $file->properties()->where('key', $id)->first();
+
+        if (!$property) {
+            return $this->errorResponse(404);
+        }
+
+        // Validate/format input
+        $v = Validator::make($request->all(), [
+                'user' => 'email|required',
+                'permissions' => 'string|required',
+        ]);
+
+        $errors = $v->fails() ? $v->errors()->toArray() : [];
+
+        $acl = self::inputAcl($request->input('permissions'));
+
+        if (empty($errors['permissions']) && empty($acl)) {
+            $errors['permissions'] = \trans('validation.file-perm-invalid');
+        }
+
+        $user = \strtolower($request->input('user'));
+
+        if (empty($errors['user']) && strpos($property->value, "$user:") !== 0) {
+            if ($file->properties()->where('key', 'like', 'share-%')->where('value', 'like', "$user:%")->exists()) {
+                $errors['user'] = \trans('validation.file-perm-exists');
+            }
+        }
+
+        if (!empty($errors)) {
+            return response()->json(['status' => 'error', 'errors' => $errors], 422);
+        }
+
+        $property->value = "$user:$acl";
+        $property->save();
+
+        $result = self::permissionToClient($property->key, $property->value);
+
+        return response()->json($result + [
+                'status' => 'success',
+                'message' => \trans('app.file-permissions-update-success'),
+        ]);
+    }
+
+    /**
+     * Listing of files (and folders).
+     *
+     * @return \Illuminate\Http\JsonResponse
+     */
+    public function index()
+    {
+        $search = trim(request()->input('search'));
+        $page = intval(request()->input('page')) ?: 1;
+        $pageSize = 100;
+        $hasMore = false;
+
+        $user = $this->guard()->user();
+
+        $result = $user->fsItems()->select('fs_items.*', 'fs_properties.value as name')
+            ->join('fs_properties', 'fs_items.id', '=', 'fs_properties.item_id')
+            ->whereNot('type', '&', Item::TYPE_INCOMPLETE)
+            ->where('key', 'name');
+
+        if (strlen($search)) {
+            $result->whereLike('fs_properties.value', $search);
+        }
+
+        $result = $result->orderBy('name')
+            ->limit($pageSize + 1)
+            ->offset($pageSize * ($page - 1))
+            ->get();
+
+        if (count($result) > $pageSize) {
+            $result->pop();
+            $hasMore = true;
+        }
+
+        // Process the result
+        $result = $result->map(
+            function ($file) {
+                $result = $this->objectToClient($file);
+                $result['name'] = $file->name; // @phpstan-ignore-line
+
+                return $result;
+            }
+        );
+
+        $result = [
+            'list' => $result,
+            'count' => count($result),
+            'hasMore' => $hasMore,
+        ];
+
+        return response()->json($result);
+    }
+
+    /**
+     * Fetch the specific file metadata or content.
+     *
+     * @param string $id The file identifier.
+     *
+     * @return \Illuminate\Http\JsonResponse|\Symfony\Component\HttpFoundation\StreamedResponse
+     */
+    public function show($id)
+    {
+        $file = $this->inputFile($id, self::READ);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        $response = $this->objectToClient($file, true);
+
+        if (request()->input('downloadUrl')) {
+            // Generate a download URL (that does not require authentication)
+            $downloadId = Utils::uuidStr();
+            Cache::add('download:' . $downloadId, $file->id, 60);
+            $response['downloadUrl'] = Utils::serviceUrl('api/v4/files/downloads/' . $downloadId);
+        } elseif (request()->input('download')) {
+            // Return the file content
+            return Storage::fileDownload($file);
+        }
+
+        $response['mtime'] = $file->updated_at->format('Y-m-d H:i');
+
+        // TODO: Handle read-write/full access rights
+        $isOwner = $this->guard()->user()->id == $file->user_id;
+        $response['canUpdate'] = $isOwner;
+        $response['canDelete'] = $isOwner;
+        $response['isOwner'] = $isOwner;
+
+        return response()->json($response);
+    }
+
+    /**
+     * Create a new file.
+     *
+     * @param \Illuminate\Http\Request $request The API request.
+     *
+     * @return \Illuminate\Http\JsonResponse The response
+     */
+    public function store(Request $request)
+    {
+        $user = $this->guard()->user();
+
+        // Validate file name input
+        $v = Validator::make($request->all(), ['name' => ['required', new FileName($user)]]);
+
+        if ($v->fails()) {
+            return response()->json(['status' => 'error', 'errors' => $v->errors()], 422);
+        }
+
+        $filename = $request->input('name');
+        $media = $request->input('media');
+
+        // FIXME: Normally people just drag and drop/upload files.
+        // The client side will not know whether the file with the same name
+        // already exists or not. So, in such a case should we throw
+        // an error or accept the request as an update?
+
+        $params = [];
+
+        if ($media == 'resumable') {
+            $params['uploadId'] = 'resumable';
+            $params['size'] = $request->input('size');
+            $params['from'] = $request->input('from') ?: 0;
+        }
+
+        // TODO: Delete the existing incomplete file with the same name?
+
+        $file = $user->fsItems()->create(['type' => Item::TYPE_INCOMPLETE | Item::TYPE_FILE]);
+        $file->setProperty('name', $filename);
+
+        try {
+            $response = Storage::fileInput($request->getContent(true), $params, $file);
+
+            $response['status'] = 'success';
+
+            if (!empty($response['id'])) {
+                $response += $this->objectToClient($file, true);
+                $response['message'] = \trans('app.file-create-success');
+            }
+        } catch (\Exception $e) {
+            \Log::error($e);
+            $file->delete();
+            return $this->errorResponse(500);
+        }
+
+        return response()->json($response);
+    }
+
+    /**
+     * Update a file.
+     *
+     * @param \Illuminate\Http\Request $request The API request.
+     * @param string                   $id      File identifier
+     *
+     * @return \Illuminate\Http\JsonResponse The response
+     */
+    public function update(Request $request, $id)
+    {
+        $file = $this->inputFile($id, self::WRITE);
+
+        if (is_int($file)) {
+            return $this->errorResponse($file);
+        }
+
+        $media = $request->input('media') ?: 'metadata';
+
+        if ($media == 'metadata') {
+            $filename = $request->input('name');
+
+            // Validate file name input
+            if ($filename != $file->getProperty('name')) {
+                $v = Validator::make($request->all(), ['name' => [new FileName($file->user)]]);
+
+                if ($v->fails()) {
+                    return response()->json(['status' => 'error', 'errors' => $v->errors()], 422);
+                }
+
+                $file->setProperty('name', $filename);
+            }
+
+            // $file->save();
+        } elseif ($media == 'resumable' || $media == 'content') {
+            $params = [];
+
+            if ($media == 'resumable') {
+                $params['uploadId'] = 'resumable';
+                $params['size'] = $request->input('size');
+                $params['from'] = $request->input('from') ?: 0;
+            }
+
+            try {
+                $response = Storage::fileInput($request->getContent(true), $params, $file);
+            } catch (\Exception $e) {
+                \Log::error($e);
+                return $this->errorResponse(500);
+            }
+        } else {
+            $errors = ['media' => \trans('validation.entryinvalid', ['attribute' => 'media'])];
+            return response()->json(['status' => 'error', 'errors' => $errors], 422);
+        }
+
+        $response['status'] = 'success';
+
+        if ($media == 'metadata' || !empty($response['id'])) {
+            $response += $this->objectToClient($file, true);
+            $response['message'] = \trans('app.file-update-success');
+        }
+
+        return response()->json($response);
+    }
+
+    /**
+     * Upload a file content.
+     *
+     * @param \Illuminate\Http\Request $request The API request.
+     * @param string                   $id      Upload (not file) identifier
+     *
+     * @return \Illuminate\Http\JsonResponse The response
+     */
+    public function upload(Request $request, $id)
+    {
+        $params = [
+            'uploadId' => $id,
+            'from' => $request->input('from') ?: 0,
+        ];
+
+        try {
+            $response = Storage::fileInput($request->getContent(true), $params);
+
+            $response['status'] = 'success';
+
+            if (!empty($response['id'])) {
+                $response += $this->objectToClient(Item::find($response['id']), true);
+                $response['message'] = \trans('app.file-upload-success');
+            }
+        } catch (\Exception $e) {
+            \Log::error($e);
+            return $this->errorResponse(500);
+        }
+
+        return response()->json($response);
+    }
+
+    /**
+     * Convert Permission to an array for the API response.
+     *
+     * @param string $id    Permission identifier
+     * @param string $value Permission record
+     *
+     * @return array Permission data
+     */
+    protected static function permissionToClient(string $id, string $value): array
+    {
+        list($user, $acl) = explode(':', $value);
+
+        $perms = strpos($acl, self::WRITE) !== false ? 'read-write' : 'read-only';
+
+        return [
+            'id' => $id,
+            'user' => $user,
+            'permissions' => $perms,
+            'link' => Utils::serviceUrl('file/' . $id),
+        ];
+    }
+
+    /**
+     * Convert ACL label into internal permissions spec.
+     *
+     * @param string $acl Access rights label
+     *
+     * @return ?string Permissions ('r' or 'rw')
+     */
+    protected static function inputAcl($acl): ?string
+    {
+        // The ACL widget supports 'full', 'read-write', 'read-only',
+        if ($acl == 'read-write') {
+            return self::READ . self::WRITE;
+        }
+
+        if ($acl == 'read-only') {
+            return self::READ;
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the input file object, check permissions
+     *
+     * @param string  $fileId     File or file permission identifier
+     * @param ?string $permission Required access rights
+     *
+     * @return \App\Fs\Item|int File object or error code
+     */
+    protected function inputFile($fileId, $permission)
+    {
+        $user = $this->guard()->user();
+        $isShare = str_starts_with($fileId, 'share-');
+
+        // Access via file permission identifier
+        if ($isShare) {
+            $property = Property::where('key', $fileId)->first();
+
+            if (!$property) {
+                return 404;
+            }
+
+            list($acl_user, $acl) = explode(':', $property->value);
+
+            if (!$permission || $acl_user != $user->email || strpos($acl, $permission) === false) {
+                return 403;
+            }
+
+            $fileId = $property->item_id;
+        }
+
+        $file = Item::find($fileId);
+
+        if (!$file) {
+            return 404;
+        }
+
+        if (!$isShare && $user->id != $file->user_id) {
+            return 403;
+        }
+
+        return $file;
+    }
+
+    /**
+     * Prepare a file object for the UI.
+     *
+     * @param object $object An object
+     * @param bool   $full   Include all object properties
+     *
+     * @return array Object information
+     */
+    protected function objectToClient($object, bool $full = false): array
+    {
+        $result = ['id' => $object->id];
+
+        if ($full) {
+            $props = array_filter($object->getProperties(['name', 'size', 'mimetype']));
+
+            $props['size'] *= 1; // convert to int
+            $result += $props;
+        }
+
+        return $result;
+    }
+}
diff --git a/src/app/Http/Controllers/API/V4/UsersController.php b/src/app/Http/Controllers/API/V4/UsersController.php
--- a/src/app/Http/Controllers/API/V4/UsersController.php
+++ b/src/app/Http/Controllers/API/V4/UsersController.php
@@ -185,6 +185,7 @@
             'enableDomains' => $isController && $hasCustomDomain,
             // TODO: Make 'enableDistlists' working for wallet controllers that aren't account owners
             'enableDistlists' => $isController && $hasCustomDomain && in_array('beta-distlists', $skus),
+            'enableFiles' => in_array('files', $skus),
             // TODO: Make 'enableFolders' working for wallet controllers that aren't account owners
             'enableFolders' => $isController && $hasCustomDomain && in_array('beta-shared-folders', $skus),
             // TODO: Make 'enableResources' working for wallet controllers that aren't account owners
diff --git a/src/app/Http/Middleware/ContentSecurityPolicy.php b/src/app/Http/Middleware/ContentSecurityPolicy.php
--- a/src/app/Http/Middleware/ContentSecurityPolicy.php
+++ b/src/app/Http/Middleware/ContentSecurityPolicy.php
@@ -25,7 +25,7 @@
 
         foreach ($headers as $opt => $header) {
             if ($value = \config("app.headers.{$opt}")) {
-                $next->header($header, $value);
+                $next->headers->set($header, $value);
             }
         }
 
diff --git a/src/app/Rules/FileName.php b/src/app/Rules/FileName.php
new file mode 100644
--- /dev/null
+++ b/src/app/Rules/FileName.php
@@ -0,0 +1,83 @@
+<?php
+
+namespace App\Rules;
+
+use Illuminate\Contracts\Validation\Rule;
+use Illuminate\Support\Facades\Validator;
+use Illuminate\Support\Str;
+
+class FileName implements Rule
+{
+    private $message;
+    private $owner;
+
+    /**
+     * Class constructor.
+     *
+     * @param \App\User $owner  The file owner
+     */
+    public function __construct($owner)
+    {
+        $this->owner = $owner;
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param string $attribute Attribute name
+     * @param mixed  $name      The value to validate
+     *
+     * @return bool
+     */
+    public function passes($attribute, $name): bool
+    {
+        if (empty($name) || !is_string($name)) {
+            $this->message = \trans('validation.file-name-invalid');
+            return false;
+        }
+
+        // Check the max length, according to the database column length
+        if (strlen($name) > 512) {
+            $this->message = \trans('validation.max.string', ['max' => 512]);
+            return false;
+        }
+
+        // Non-allowed characters
+        if (preg_match('|[\x00-\x1F\/*"\x7F]|', $name)) {
+            $this->message = \trans('validation.file-name-invalid');
+            return false;
+        }
+
+        // Leading/trailing spaces, or all spaces
+        if (preg_match('|^\s+$|', $name) || preg_match('|^\s+|', $name) || preg_match('|\s+$|', $name)) {
+            $this->message = \trans('validation.file-name-invalid');
+            return false;
+        }
+
+        // FIXME: Should we require a dot?
+
+        // Check if the name is unique
+        $exists = $this->owner->fsItems()
+            ->join('fs_properties', 'fs_items.id', '=', 'fs_properties.item_id')
+            ->where('key', 'name')
+            ->where('value', $name)
+            ->exists();
+
+        if ($exists) {
+            $this->message = \trans('validation.file-name-exists');
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message(): ?string
+    {
+        return $this->message;
+    }
+}
diff --git a/src/app/User.php b/src/app/User.php
--- a/src/app/User.php
+++ b/src/app/User.php
@@ -348,6 +348,16 @@
         return null;
     }
 
+    /**
+     * Storage items for this user.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function fsItems()
+    {
+        return $this->hasMany(Fs\Item::class);
+    }
+
     /**
      * Return groups controlled by the current user.
      *
diff --git a/src/app/Wallet.php b/src/app/Wallet.php
--- a/src/app/Wallet.php
+++ b/src/app/Wallet.php
@@ -27,6 +27,7 @@
     use SettingsTrait;
     use UuidStrKeyTrait;
 
+    /** @var bool Indicates that the model should be timestamped or not */
     public $timestamps = false;
 
     /** @var array The attributes' default values */
diff --git a/src/config/filesystems.php b/src/config/filesystems.php
--- a/src/config/filesystems.php
+++ b/src/config/filesystems.php
@@ -35,6 +35,11 @@
             'root' => storage_path('app'),
         ],
 
+        'files' => [
+            'driver' => 'local',
+            'root' => storage_path('app/files'),
+        ],
+
         'pgp' => [
             'driver' => 'local',
             'root' => storage_path('app/keys'),
diff --git a/src/config/octane.php b/src/config/octane.php
--- a/src/config/octane.php
+++ b/src/config/octane.php
@@ -230,7 +230,7 @@
     'swoole' => [
         'options' => [
             'log_file' => storage_path('logs/swoole_http.log'),
-            'package_max_length' => 10 * 1024 * 1024,
+            'package_max_length' => env('SWOOLE_PACKAGE_MAX_LENGTH', 10 * 1024 * 1024),
             'enable_coroutine' => false,
             //FIXME the daemonize option does not work
             // 'daemonize' => env('OCTANE_DAEMONIZE', true),
diff --git a/src/database/migrations/2022_03_02_100000_create_filesystem_tables.php b/src/database/migrations/2022_03_02_100000_create_filesystem_tables.php
new file mode 100644
--- /dev/null
+++ b/src/database/migrations/2022_03_02_100000_create_filesystem_tables.php
@@ -0,0 +1,89 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create(
+            'fs_items',
+            function (Blueprint $table) {
+                $table->string('id', 36)->primary();
+                $table->bigInteger('user_id')->index();
+                $table->integer('type')->unsigned()->default(0);
+
+                $table->timestamps();
+                $table->softDeletes();
+
+                $table->foreign('user_id')->references('id')->on('users')
+                    ->onUpdate('cascade')->onDelete('cascade');
+            }
+        );
+
+        Schema::create(
+            'fs_properties',
+            function (Blueprint $table) {
+                $table->bigIncrements('id');
+                $table->string('item_id', 36);
+                $table->string('key')->index();
+                $table->text('value');
+
+                $table->timestamps();
+
+                $table->unique(['item_id', 'key']);
+
+                $table->foreign('item_id')->references('id')->on('fs_items')
+                    ->onDelete('cascade')->onUpdate('cascade');
+            }
+        );
+
+        Schema::create(
+            'fs_chunks',
+            function (Blueprint $table) {
+                $table->bigIncrements('id');
+                $table->string('item_id', 36);
+                $table->string('chunk_id', 36);
+                $table->integer('sequence')->default(0);
+                $table->integer('size')->unsigned()->default(0);
+
+                $table->timestamps();
+                $table->softDeletes();
+
+                $table->unique(['item_id', 'chunk_id']);
+                // $table->unique(['item_id', 'sequence', 'deleted_at']);
+
+                $table->foreign('item_id')->references('id')->on('fs_items')
+                    ->onUpdate('cascade')->onDelete('cascade');
+            }
+        );
+
+        if (!\App\Sku::where('title', 'files')->first()) {
+            \App\Sku::create([
+                'title' => 'files',
+                'name' => 'File storage',
+                'description' => 'Access to file storage',
+                'cost' => 0,
+                'units_free' => 0,
+                'period' => 'monthly',
+                'handler_class' => 'App\Handlers\Files',
+                'active' => true,
+            ]);
+        }
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('fs_properties');
+        Schema::dropIfExists('fs_chunks');
+        Schema::dropIfExists('fs_items');
+    }
+};
diff --git a/src/database/seeds/local/SkuSeeder.php b/src/database/seeds/local/SkuSeeder.php
--- a/src/database/seeds/local/SkuSeeder.php
+++ b/src/database/seeds/local/SkuSeeder.php
@@ -256,6 +256,22 @@
             ]);
         }
 
+        // Check existence because migration might have added this already
+        $sku = Sku::where(['title' => 'files', 'tenant_id' => \config('app.tenant_id')])->first();
+
+        if (!$sku) {
+            Sku::create([
+                'title' => 'files',
+                'name' => 'File storage',
+                'description' => 'Access to file storage',
+                'cost' => 0,
+                'units_free' => 0,
+                'period' => 'monthly',
+                'handler_class' => 'App\Handlers\Files',
+                'active' => true,
+            ]);
+        }
+
         // for tenants that are not the configured tenant id
         $tenants = \App\Tenant::where('id', '!=', \config('app.tenant_id'))->get();
 
diff --git a/src/database/seeds/production/SkuSeeder.php b/src/database/seeds/production/SkuSeeder.php
--- a/src/database/seeds/production/SkuSeeder.php
+++ b/src/database/seeds/production/SkuSeeder.php
@@ -241,5 +241,19 @@
                 'active' => true,
             ]);
         }
+
+        // Check existence because migration might have added this already
+        if (!Sku::where('title', 'files')->first()) {
+            Sku::create([
+                'title' => 'files',
+                'name' => 'File storage',
+                'description' => 'Access to file storage',
+                'cost' => 0,
+                'units_free' => 0,
+                'period' => 'monthly',
+                'handler_class' => 'App\Handlers\Files',
+                'active' => true,
+            ]);
+        }
     }
 }
diff --git a/src/resources/js/app.js b/src/resources/js/app.js
--- a/src/resources/js/app.js
+++ b/src/resources/js/app.js
@@ -161,7 +161,7 @@
             //       while the token is being refreshed
 
             this.refreshTimeout = setTimeout(() => {
-                axios.post('/api/auth/refresh', {'refresh_token': response.refresh_token}).then(response => {
+                axios.post('api/auth/refresh', { refresh_token: response.refresh_token }).then(response => {
                     this.loginUser(response.data, false, true)
                 })
             }, timeout * 1000)
@@ -255,7 +255,7 @@
                 this.errorPage(status, message)
             }
         },
-        downloadFile(url) {
+        downloadFile(url, filename) {
             // TODO: This might not be a best way for big files as the content
             //       will be stored (temporarily) in browser memory
             // TODO: This method does not show the download progress in the browser
@@ -263,13 +263,16 @@
             axios.get(url, { responseType: 'blob' })
                 .then(response => {
                     const link = document.createElement('a')
-                    const contentDisposition = response.headers['content-disposition']
-                    let filename = 'unknown'
 
-                    if (contentDisposition) {
-                        const match = contentDisposition.match(/filename="(.+)"/);
-                        if (match.length === 2) {
-                            filename = match[1];
+                    if (!filename) {
+                        const contentDisposition = response.headers['content-disposition']
+                        filename = 'unknown'
+
+                        if (contentDisposition) {
+                            const match = contentDisposition.match(/filename="?(.+)"?/);
+                            if (match && match.length === 2) {
+                                filename = match[1];
+                            }
                         }
                     }
 
diff --git a/src/resources/js/files.js b/src/resources/js/files.js
new file mode 100644
--- /dev/null
+++ b/src/resources/js/files.js
@@ -0,0 +1,191 @@
+
+function FileAPI(params = {})
+{
+    // Initial max size of a file chunk in an upload request
+    // Note: The value may change to the value provided by the server on the first upload.
+    // Note: That chunk size here is only body, Swoole's package_max_length is body + headers,
+    // so don't forget to subtract some margin (e.g. 8KB)
+    // FIXME: From my preliminary tests it looks like on the PHP side you need
+    // about 3-4 times as much memory as the request size when using Swoole
+    // (only 1 time without Swoole). And I didn't find a way to lower the memory usage,
+    // it looks like it happens before we even start to process the request in FilesController.
+    let maxChunkSize = 5 * 1024 * 1024 - 1024 * 8
+
+    const area = $(params.dropArea)
+
+    // Add hidden input to the drop area, so we can handle upload by click
+    const input = $('<input>')
+        .attr({type: 'file', multiple: true, style: 'visibility: hidden'})
+        .on('change', event => { fileDropHandler(event) })
+        .appendTo(area)
+        .get(0)
+
+    // Register events on the upload area element
+    area.on('click', () => input.click())
+        .on('drop', event => fileDropHandler(event))
+        .on('dragenter dragleave drop', event => fileDragHandler(event))
+        .on('dragover', event => event.preventDefault()) // prevents file from being opened on drop)
+
+    // Handle dragging on the whole page, so we can style the area in a different way
+    $(document.documentElement).off('.fileapi')
+        .on('dragenter.fileapi dragleave.fileapi', event => area.toggleClass('dragactive'))
+
+    // Handle dragging file(s) - style the upload area element
+    const fileDragHandler = (event) => {
+        if (event.type == 'drop') {
+            area.removeClass('dragover dragactive')
+        } else {
+            area[event.type == 'dragenter' ? 'addClass' : 'removeClass']('dragover')
+        }
+    }
+
+    // Handler for both a ondrop event and file input onchange event
+    const fileDropHandler = (event) => {
+        let files = event.target.files || event.dataTransfer.files
+
+        if (!files || !files.length) {
+            return
+        }
+
+        // Prevent default behavior (prevent file from being opened on drop)
+        event.preventDefault();
+
+        // TODO: Check file size limit, limit number of files to upload at once?
+
+        // For every file...
+        for (const file of files) {
+            const progress = {
+                id: Date.now(),
+                name: file.name,
+                total: file.size,
+                completed: 0
+            }
+
+            file.uploaded = 0
+
+            // Upload request configuration
+            const config = {
+                onUploadProgress: progressEvent => {
+                    progress.completed = Math.round(((file.uploaded + progressEvent.loaded) * 100) / file.size)
+
+                    // Don't trigger the event when 100% of the file has been sent
+                    // We need to wait until the request response is available, then
+                    // we'll trigger it (see below where the axios request is created)
+                    if (progress.completed < 100) {
+                        params.eventHandler('upload-progress', progress)
+                    }
+                },
+                headers: {
+                    'Content-Type': file.type
+                },
+                ignoreErrors: true, // skip the Kolab4 interceptor
+                params: { name: file.name },
+                maxBodyLength: -1, // no limit
+                timeout: 0, // no limit
+                transformRequest: [] // disable body transformation
+            }
+
+            // FIXME: It might be better to handle multiple-files upload as a one
+            // "progress source", i.e. we might want to refresh the files list once
+            // all files finished uploading, not multiple times in the middle
+            // of the upload process.
+
+            params.eventHandler('upload-progress', progress)
+
+            // A "recursive" function to upload the file in chunks (if needed)
+            const uploadFn = (start = 0, uploadId) => {
+                let url = 'api/v4/files'
+                let body = ''
+
+                if (file.size <= maxChunkSize) {
+                    // The file is small, we'll upload it using a single request
+                    // Note that even in this case the auth token might expire while
+                    // the file is uploading, but the risk is quite small.
+                    body = file
+                    start += maxChunkSize
+                } else if (!uploadId) {
+                    // The file is big, first send a request for the upload location
+                    // The upload location does not require authentication, which means
+                    // there should be no problem with expired auth token, etc.
+                    config.params.media = 'resumable'
+                    config.params.size = file.size
+                } else {
+                    // Upload a chunk of the file to the upload location
+                    url = 'api/v4/files/uploads/' + uploadId
+                    body = file.slice(start, start + maxChunkSize, file.type)
+
+                    config.params = { from: start }
+                    config.headers.Authorization = ''
+                    start += maxChunkSize
+                }
+
+                axios.post(url, body, config)
+                    .then(response => {
+                        if (response.data.maxChunkSize) {
+                            maxChunkSize = response.data.maxChunkSize
+                        }
+
+                        if (start < file.size) {
+                            file.uploaded = start
+                            uploadFn(start, uploadId || response.data.uploadId)
+                        } else {
+                            progress.completed = 100
+                            params.eventHandler('upload-progress', progress)
+                        }
+                    })
+                    .catch(error => {
+                        console.log(error)
+
+                        // TODO: Depending on the error consider retrying the request
+                        // if it was one of many chunks of a bigger file?
+
+                        progress.error = error
+                        progress.completed = 100
+                        params.eventHandler('upload-progress', progress)
+                    })
+            }
+
+            // Start uploading
+            uploadFn()
+        }
+    }
+
+    /**
+     * Download a file. Starts downloading using a hidden link trick.
+     */
+    this.fileDownload = (id) => {
+        axios.get('api/v4/files/' + id + '?downloadUrl=1')
+            .then(response => {
+                // Create a dummy link element and click it
+                if (response.data.downloadUrl) {
+                    $('<a>').attr('href', response.data.downloadUrl).get(0).click()
+                }
+            })
+    }
+
+    /**
+     * Rename a file.
+     */
+    this.fileRename = (id, name) => {
+        axios.put('api/v4/files/' + id, { name })
+            .then(response => {
+
+            })
+    }
+
+    /**
+     * Convert file size as a number of bytes to a human-readable format
+     */
+    this.sizeText = (bytes) => {
+        if (bytes >= 1073741824)
+            return parseFloat(bytes/1073741824).toFixed(2) + ' GB';
+        if (bytes >= 1048576)
+            return parseFloat(bytes/1048576).toFixed(2) + ' MB';
+        if (bytes >= 1024)
+            return parseInt(bytes/1024) + ' kB';
+
+        return parseInt(bytes || 0) + ' B';
+    }
+}
+
+export default FileAPI
diff --git a/src/resources/js/user/routes.js b/src/resources/js/user/routes.js
--- a/src/resources/js/user/routes.js
+++ b/src/resources/js/user/routes.js
@@ -14,6 +14,8 @@
 const DistlistListComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Distlist/List')
 const DomainInfoComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Domain/Info')
 const DomainListComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Domain/List')
+const FileInfoComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/File/Info')
+const FileListComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/File/List')
 const MeetComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Rooms')
 const ResourceInfoComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Resource/Info')
 const ResourceListComponent = () => import(/* webpackChunkName: "../user/pages" */ '../../vue/Resource/List')
@@ -64,6 +66,18 @@
         component: DomainListComponent,
         meta: { requiresAuth: true, perm: 'domains' }
     },
+    {
+        path: '/file/:file',
+        name: 'file',
+        component: FileInfoComponent,
+        meta: { requiresAuth: true /*, perm: 'files' */ }
+    },
+    {
+        path: '/files',
+        name: 'files',
+        component: FileListComponent,
+        meta: { requiresAuth: true, perm: 'files' }
+    },
     {
         path: '/login',
         name: 'login',
diff --git a/src/resources/lang/en/app.php b/src/resources/lang/en/app.php
--- a/src/resources/lang/en/app.php
+++ b/src/resources/lang/en/app.php
@@ -70,6 +70,13 @@
     'domain-unsuspend-success' => 'Domain unsuspended successfully.',
     'domain-setconfig-success' => 'Domain settings updated successfully.',
 
+    'file-create-success' => 'File created successfully.',
+    'file-delete-success' => 'File deleted successfully.',
+    'file-update-success' => 'File updated successfully.',
+    'file-permissions-create-success' => 'File permissions created successfully.',
+    'file-permissions-update-success' => 'File permissions updated successfully.',
+    'file-permissions-delete-success' => 'File permissions deleted successfully.',
+
     'resource-update-success' => 'Resource updated successfully.',
     'resource-create-success' => 'Resource created successfully.',
     'resource-delete-success' => 'Resource deleted successfully.',
diff --git a/src/resources/lang/en/ui.php b/src/resources/lang/en/ui.php
--- a/src/resources/lang/en/ui.php
+++ b/src/resources/lang/en/ui.php
@@ -31,6 +31,7 @@
         'resend' => "Resend",
         'save' => "Save",
         'search' => "Search",
+        'share' => "Share",
         'signup' => "Sign Up",
         'submit' => "Submit",
         'suspend' => "Suspend",
@@ -60,6 +61,7 @@
         'chat' => "Video chat",
         'companion' => "Companion app",
         'domains' => "Domains",
+        'files' => "Files",
         'invitations' => "Invitations",
         'profile' => "Your profile",
         'resources' => "Resources",
@@ -126,6 +128,19 @@
         'form' => "Form validation error",
     ],
 
+    'file' => [
+        'create' => "Create file",
+        'delete' => "Delete file",
+        'list-empty' => "There are no files in this account.",
+        'mimetype' => "Mimetype",
+        'mtime' => "Modified",
+        'new' => "New file",
+        'search' => "File name",
+        'sharing' => "Sharing",
+        'sharing-links-text' => "You can share the file with other users by giving them read-only access "
+            . "to the file via a unique link.",
+    ],
+
     'form' => [
         'acl' => "Access rights",
         'acl-full' => "All",
@@ -154,6 +169,7 @@
         'phone' => "Phone",
         'settings' => "Settings",
         'shared-folder' => "Shared Folder",
+        'size' => "Size",
         'status' => "Status",
         'surname' => "Surname",
         'type' => "Type",
@@ -302,6 +318,7 @@
         'notfound' => "Resource not found.",
         'info' => "Information",
         'error' => "Error",
+        'uploading' => "Uploading...",
         'warning' => "Warning",
         'success' => "Success",
     ],
diff --git a/src/resources/lang/en/validation.php b/src/resources/lang/en/validation.php
--- a/src/resources/lang/en/validation.php
+++ b/src/resources/lang/en/validation.php
@@ -153,6 +153,11 @@
     'spf-entry-invalid' => 'The entry format is invalid. Expected a domain name starting with a dot.',
     'sp-entry-invalid' => 'The entry format is invalid. Expected an email, domain, or part of it.',
     'acl-entry-invalid' => 'The entry format is invalid. Expected an email address.',
+    'file-perm-exists' => 'File permission already exists.',
+    'file-perm-invalid' => 'The file permission is invalid.',
+    'file-name-exists' => 'The file name already exists.',
+    'file-name-invalid' => 'The file name is invalid.',
+    'file-name-toolong' => 'The file name is too long.',
     'ipolicy-invalid' => 'The specified invitation policy is invalid.',
     'invalid-config-parameter' => 'The requested configuration parameter is not supported.',
     'nameexists' => 'The specified name is not available.',
diff --git a/src/resources/themes/app.scss b/src/resources/themes/app.scss
--- a/src/resources/themes/app.scss
+++ b/src/resources/themes/app.scss
@@ -137,7 +137,9 @@
 
     td.buttons,
     th.price,
-    td.price {
+    td.price,
+    th.size,
+    td.size {
         width: 1%;
         text-align: right;
         white-space: nowrap;
@@ -174,6 +176,38 @@
             margin-left: .4em;
         }
     }
+
+    &.files {
+        table-layout: fixed;
+
+        td {
+            white-space: nowrap;
+        }
+
+        td.name {
+            overflow: hidden;
+            text-overflow: ellipsis;
+        }
+/*
+        td.size,
+        th.size {
+            width: 80px;
+        }
+
+        td.mtime,
+        th.mtime {
+            width: 140px;
+
+            @include media-breakpoint-down(sm) {
+                display: none;
+            }
+        }
+*/
+        td.buttons,
+        th.buttons {
+            width: 50px;
+        }
+    }
 }
 
 .list-details {
diff --git a/src/resources/themes/forms.scss b/src/resources/themes/forms.scss
--- a/src/resources/themes/forms.scss
+++ b/src/resources/themes/forms.scss
@@ -169,3 +169,32 @@
         }
     }
 }
+
+.file-drop-area {
+    display: inline;
+    background: $menu-bg-color;
+    color: grey;
+    font-size: 0.9rem;
+    font-weight: normal;
+    line-height: 2;
+    border: 1px solid #eee;
+    border-radius: 0.5em;
+    padding: 0.5em;
+    cursor: pointer;
+    position: relative;
+
+    input {
+        position: absolute;
+        height: 10px;
+    }
+
+    &.dragactive {
+        border: 1px dashed #aaa;
+    }
+
+    &.dragover {
+        background-color: rgba($main-color, 0.25);
+        border: 1px dashed $main-color;
+        color: $main-color;
+    }
+}
diff --git a/src/resources/themes/toast.scss b/src/resources/themes/toast.scss
--- a/src/resources/themes/toast.scss
+++ b/src/resources/themes/toast.scss
@@ -51,3 +51,17 @@
 .toast-body {
     color: #fff;
 }
+
+.toast-progress {
+    margin: 0.5em;
+    margin-top: 0;
+    height: 3px;
+    background: #222;
+    border-radius: 1.5px;
+    overflow: hidden;
+}
+
+.toast-progress-bar {
+    height: 100%;
+    background: $main-color;
+}
diff --git a/src/resources/vue/Dashboard.vue b/src/resources/vue/Dashboard.vue
--- a/src/resources/vue/Dashboard.vue
+++ b/src/resources/vue/Dashboard.vue
@@ -32,6 +32,10 @@
                 <svg-icon icon="comments"></svg-icon><span class="name">{{ $t('dashboard.chat') }}</span>
                 <span class="badge bg-primary">{{ $t('dashboard.beta') }}</span>
             </router-link>
+            <router-link v-if="status.enableFiles && !$root.isDegraded()" class="card link-files" :to="{ name: 'files' }">
+                <svg-icon icon="folder-open"></svg-icon><span class="name">{{ $t('dashboard.files') }}</span>
+                <span class="badge bg-primary">{{ $t('dashboard.beta') }}</span>
+            </router-link>
             <router-link v-if="status.enableSettings" class="card link-settings" :to="{ name: 'settings' }">
                 <svg-icon icon="sliders-h"></svg-icon><span class="name">{{ $t('dashboard.settings') }}</span>
             </router-link>
diff --git a/src/resources/vue/File/Info.vue b/src/resources/vue/File/Info.vue
new file mode 100644
--- /dev/null
+++ b/src/resources/vue/File/Info.vue
@@ -0,0 +1,163 @@
+<template>
+    <div class="container">
+        <div class="card" id="file-info">
+            <div class="card-body">
+                <div class="card-title">
+                    {{ file.name }}
+                    <btn v-if="file.canDelete" class="btn-outline-danger button-delete float-end" @click="fileDelete" icon="trash-alt">{{ $t('file.delete') }}</btn>
+                </div>
+                <div class="card-text">
+                    <ul class="nav nav-tabs mt-3" role="tablist">
+                        <li class="nav-item">
+                            <a class="nav-link active" id="tab-general" href="#general" role="tab" aria-controls="general" aria-selected="true" @click="$root.tab">
+                                {{ $t('form.general') }}
+                            </a>
+                        </li>
+                        <li class="nav-item" v-if="file.isOwner">
+                            <a class="nav-link" id="tab-sharing" href="#sharing" role="tab" aria-controls="sharing" aria-selected="false" @click="$root.tab">
+                                {{ $t('file.sharing') }}
+                            </a>
+                        </li>
+                    </ul>
+                    <div class="tab-content">
+                        <form class="tab-pane show active card-body read-only short" id="general" role="tabpanel" aria-labelledby="tab-general">
+                            <div class="row plaintext">
+                                <label for="mimetype" class="col-sm-4 col-form-label">{{ $t('file.mimetype') }}</label>
+                                <div class="col-sm-8">
+                                    <span class="form-control-plaintext" id="mimetype">{{ file.mimetype }}</span>
+                                </div>
+                            </div>
+                            <div class="row plaintext">
+                                <label for="size" class="col-sm-4 col-form-label">{{ $t('form.size') }}</label>
+                                <div class="col-sm-8">
+                                    <span class="form-control-plaintext" id="size">{{ api.sizeText(file.size) }}</span>
+                                </div>
+                            </div>
+                            <div class="row plaintext mb-3">
+                                <label for="mtime" class="col-sm-4 col-form-label">{{ $t('file.mtime') }}</label>
+                                <div class="col-sm-8">
+                                    <span class="form-control-plaintext" id="mtime">{{ file.mtime }}</span>
+                                </div>
+                            </div>
+                            <btn class="btn-primary" icon="download" @click="fileDownload">{{ $t('btn.download') }}</btn>
+                        </form>
+                        <div v-if="file.isOwner" class="tab-pane card-body" id="sharing" role="tabpanel" aria-labelledby="tab-sharing">
+                            <div id="share-form" class="mb-3">
+                                <div class="row">
+                                    <small id="share-links-hint" class="text-muted mb-2">
+                                        {{ $t('file.sharing-links-text') }}
+                                    </small>
+                                    <div class="input-group">
+                                        <input type="text" class="form-control" id="user" :placeholder="$t('form.email')">
+                                        <a href="#" class="btn btn-outline-secondary" @click.prevent="shareAdd">
+                                            <svg-icon icon="plus"></svg-icon><span class="visually-hidden">{{ $t('btn.add') }}</span>
+                                        </a>
+                                    </div>
+                                </div>
+                            </div>
+                            <div id="share-links" class="row m-0" v-if="shares.length">
+                                <div class="list-group p-0">
+                                    <div v-for="(item, index) in shares" :key="item.id" class="list-group-item">
+                                        <div class="d-flex w-100 justify-content-between">
+                                            <span class="user lh-lg">
+                                                <svg-icon icon="user"></svg-icon> {{ item.user }}
+                                            </span>
+                                            <span class="d-inline-block">
+                                                <btn class="btn-link p-1" :icon="['far', 'clipboard']" :title="$t('btn.copy')" @click="copyLink(item.link)"></btn>
+                                                <btn class="btn-link text-danger p-1" icon="trash-alt" :title="$t('btn.delete')" @click="shareDelete(item.id)"></btn>
+                                            </span>
+                                        </div>
+                                        <code>{{ item.link }}</code>
+                                    </div>
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+</template>
+
+<script>
+    import FileAPI from '../../js/files.js'
+
+    import { library } from '@fortawesome/fontawesome-svg-core'
+    import { faDownload } from '@fortawesome/free-solid-svg-icons'
+
+    library.add(faDownload)
+
+    export default {
+        data() {
+            return {
+                file: {},
+                fileId: null,
+                shares: []
+            }
+        },
+        created() {
+            this.api = new FileAPI({})
+
+            this.fileId = this.$route.params.file
+
+            this.$root.startLoading()
+
+            axios.get('/api/v4/files/' + this.fileId)
+                .then(response => {
+                    this.$root.stopLoading()
+                    this.file = response.data
+
+                    if (this.file.isOwner) {
+                        axios.get('api/v4/files/' + this.fileId + '/permissions')
+                            .then(response => {
+                                if (response.data.list) {
+                                    this.shares = response.data.list
+                                }
+                            })
+                    }
+                })
+                .catch(this.$root.errorHandler)
+        },
+        methods: {
+            copyLink(link) {
+                navigator.clipboard.writeText(link);
+            },
+            fileDelete() {
+                axios.delete('api/v4/files/' + this.fileId)
+                    .then(response => {
+                        if (response.data.status == 'success') {
+                            this.$toast.success(response.data.message)
+                            this.$router.push({ name: 'files' })
+                        }
+                    })
+            },
+            fileDownload() {
+                this.api.fileDownload(this.fileId)
+            },
+            shareAdd() {
+                let post = { permissions: 'read-only', user: $('#user').val() }
+
+                if (!post.user) {
+                    return
+                }
+
+                axios.post('api/v4/files/' + this.fileId + '/permissions', post)
+                    .then(response => {
+                        if (response.data.status == 'success') {
+                            this.$toast.success(response.data.message)
+                            this.shares.push(response.data)
+                        }
+                    })
+            },
+            shareDelete(id) {
+                axios.delete('api/v4/files/' + this.fileId + '/permissions/' + id)
+                    .then(response => {
+                        if (response.data.status == 'success') {
+                            this.$toast.success(response.data.message)
+                            this.$delete(this.shares, this.shares.findIndex(element => element.id == id))
+                        }
+                    })
+            }
+        }
+    }
+</script>
diff --git a/src/resources/vue/File/List.vue b/src/resources/vue/File/List.vue
new file mode 100644
--- /dev/null
+++ b/src/resources/vue/File/List.vue
@@ -0,0 +1,133 @@
+<template>
+    <div class="container">
+        <div class="card" id="files">
+            <div class="card-body">
+                <div class="card-title">
+                    {{ $t('dashboard.files') }}
+                    <small><sup class="badge bg-primary">{{ $t('dashboard.beta') }}</sup></small>
+                    <div id="drop-area" class="file-drop-area float-end">
+                        <svg-icon icon="upload"></svg-icon> Click or drop file(s) here
+                    </div>
+                </div>
+                <div class="card-text pt-4">
+                    <div class="mb-2 d-flex w-100">
+                        <list-search :placeholder="$t('file.search')" :on-search="searchFiles"></list-search>
+                    </div>
+                    <table class="table table-sm table-hover files">
+                        <thead>
+                            <tr>
+                                <th scope="col" class="name">{{ $t('form.name') }}</th>
+                                <th scope="col" class="buttons"></th>
+                            </tr>
+                        </thead>
+                        <tbody>
+                            <tr v-for="file in files" :key="file.id" @click="$root.clickRecord">
+                                <td class="name">
+                                    <svg-icon icon="file" :title="file.mimetype"></svg-icon>
+                                    <router-link :to="{ path: 'file/' + file.id }">{{ file.name }}</router-link>
+                                </td>
+                                <td class="buttons">
+                                    <btn class="button-download p-0 ms-1" @click="fileDownload(file)" icon="download" :title="$t('btn.download')"></btn>
+                                    <btn class="button-delete text-danger p-0 ms-1" @click="fileDelete(file)" icon="trash-alt" :title="$t('btn.delete')"></btn>
+                                </td>
+                            </tr>
+                        </tbody>
+                        <list-foot :colspan="2" :text="$t('file.list-empty')"></list-foot>
+                    </table>
+                    <list-more v-if="hasMore" :on-click="loadFiles"></list-more>
+                </div>
+            </div>
+        </div>
+    </div>
+</template>
+
+<script>
+    import FileAPI from '../../js/files.js'
+    import ListTools from '../Widgets/ListTools'
+
+    import { library } from '@fortawesome/fontawesome-svg-core'
+    import { faFile, faDownload, faUpload } from '@fortawesome/free-solid-svg-icons'
+
+    library.add(faFile, faDownload, faUpload)
+
+    export default {
+        mixins: [ ListTools ],
+        data() {
+            return {
+                api: {},
+                file: null,
+                files: []
+            }
+        },
+        mounted() {
+            this.uploads = {}
+
+            this.api = new FileAPI({
+                    dropArea: '#drop-area',
+                    eventHandler: this.eventHandler
+            })
+
+            this.loadFiles({ init: true })
+        },
+        methods: {
+            eventHandler(name, params) {
+                const camelCase = name.toLowerCase().replace(/[^a-zA-Z0-9]+(.)/g, (m, chr) => chr.toUpperCase())
+                const method = camelCase + 'Handler'
+
+                if (method in this) {
+                    this[method](params)
+                }
+            },
+            fileDelete(file) {
+                axios.delete('api/v4/files/' + file.id)
+                    .then(response => {
+                        if (response.data.status == 'success') {
+                            this.$toast.success(response.data.message)
+                            // Refresh the list
+                            this.loadFiles({ reset: true })
+                        }
+                    })
+            },
+            fileDownload(file) {
+                // This is not an appropriate method for big files, we can consider
+                // using it still for very small files.
+                // this.$root.downloadFile('api/v4/files/' + file.id + '?download=1', file.name)
+
+                // This method first makes a request to the API to get the download URL (which does not
+                // require authentication) and then use it to download the file.
+                this.api.fileDownload(file.id)
+            },
+            loadFiles(params) {
+                this.listSearch('files', 'api/v4/files', params)
+            },
+            searchFiles(search) {
+                this.loadFiles({ reset: true, search })
+            },
+            uploadProgressHandler(params) {
+                // Note: There might be more than one event with completed=0
+                // e.g. if you upload multiple files at once
+                if (params.completed == 0 && !(params.id in this.uploads)) {
+                    // Create the toast message with progress bar
+                    this.uploads[params.id] = this.$toast.message({
+                        icon: 'upload',
+                        timeout: 24 * 60 * 60 * 60 * 1000,
+                        title: this.$t('msg.uploading'),
+                        msg: `${params.name} (${this.api.sizeText(params.total)})`,
+                        progress: 0
+                    })
+                } else if (params.id in this.uploads) {
+                    if (params.completed == 100) {
+                        this.uploads[params.id].delete() // close the toast message
+                        delete this.uploads[params.id]
+
+                        // TODO: Reloading the list is probably not the best solution
+                        this.loadFiles({ reset: true })
+                    } else {
+                        // update progress bar
+                        this.uploads[params.id].updateProgress(params.completed)
+                    }
+                }
+            }
+        }
+    }
+</script>
diff --git a/src/resources/vue/Widgets/AclInput.vue b/src/resources/vue/Widgets/AclInput.vue
--- a/src/resources/vue/Widgets/AclInput.vue
+++ b/src/resources/vue/Widgets/AclInput.vue
@@ -1,7 +1,7 @@
 <template>
     <div class="list-input acl-input" :id="id">
         <div class="input-group">
-            <select class="form-select mod mod-user" @change="changeMod" v-model="mod">
+            <select v-if="!useronly" class="form-select mod mod-user" @change="changeMod" v-model="mod">
                 <option value="user">{{ $t('form.user') }}</option>
                 <option value="anyone">{{ $t('form.anyone') }}</option>
             </select>
@@ -29,7 +29,8 @@
     export default {
         props: {
             list: { type: Array, default: () => [] },
-            id: { type: String, default: '' }
+            id: { type: String, default: '' },
+            useronly: { type: Boolean, default: false }
         },
         data() {
             return {
diff --git a/src/resources/vue/Widgets/ListTools.vue b/src/resources/vue/Widgets/ListTools.vue
--- a/src/resources/vue/Widgets/ListTools.vue
+++ b/src/resources/vue/Widgets/ListTools.vue
@@ -53,7 +53,7 @@
         methods: {
             listSearch(name, url, params) {
                 let loader
-                let get = {}
+                let get = params.get || {}
 
                 if (params) {
                     if (params.reset || params.init) {
diff --git a/src/resources/vue/Widgets/Toast.vue b/src/resources/vue/Widgets/Toast.vue
--- a/src/resources/vue/Widgets/Toast.vue
+++ b/src/resources/vue/Widgets/Toast.vue
@@ -14,6 +14,8 @@
                 const instance = new msg({ propsData: { data: data } })
                 instance.$mount()
                 $(instance.$el).prependTo(this.$el)
+
+                return instance
             },
             processObjectData(data) {
                 if (typeof data === 'object' && data.msg !== undefined) {
diff --git a/src/resources/vue/Widgets/ToastMessage.vue b/src/resources/vue/Widgets/ToastMessage.vue
--- a/src/resources/vue/Widgets/ToastMessage.vue
+++ b/src/resources/vue/Widgets/ToastMessage.vue
@@ -11,6 +11,9 @@
         </div>
         <div v-if="data.body" v-html="data.body" class="toast-body"></div>
         <div v-else class="toast-body">{{ data.msg }}</div>
+        <div v-if="'progress' in data" class="toast-progress">
+            <div class="toast-progress-bar" :style="'width: ' + data.progress + '%'"></div>
+        </div>
     </div>
 </template>
 
@@ -52,9 +55,15 @@
                         return this.data.titleClassName || ''
                 }
             },
+            delete() {
+                new Toast(this.$el).dispose()
+            },
             toastClassName() {
                 return 'toast hide toast-' + this.data.type
                     + (this.data.className ? ' ' + this.data.className : '')
+            },
+            updateProgress(percent) {
+                $(this.$el).find('.toast-progress-bar').css('width', percent + '%')
             }
         }
     }
diff --git a/src/routes/api.php b/src/routes/api.php
--- a/src/routes/api.php
+++ b/src/routes/api.php
@@ -81,6 +81,17 @@
         Route::get('domains/{id}/status', [API\V4\DomainsController::class, 'status']);
         Route::post('domains/{id}/config', [API\V4\DomainsController::class, 'setConfig']);
 
+        Route::apiResource('files', API\V4\FilesController::class);
+        Route::get('files/{fileId}/permissions', [API\V4\FilesController::class, 'getPermissions']);
+        Route::post('files/{fileId}/permissions', [API\V4\FilesController::class, 'createPermission']);
+        Route::put('files/{fileId}/permissions/{id}', [API\V4\FilesController::class, 'updatePermission']);
+        Route::delete('files/{fileId}/permissions/{id}', [API\V4\FilesController::class, 'deletePermission']);
+        Route::post('files/uploads/{id}', [API\V4\FilesController::class, 'upload'])
+            ->withoutMiddleware(['auth:api'])
+            ->middleware(['api']);
+        Route::get('files/downloads/{id}', [API\V4\FilesController::class, 'download'])
+            ->withoutMiddleware(['auth:api']);
+
         Route::apiResource('groups', API\V4\GroupsController::class);
         Route::get('groups/{id}/status', [API\V4\GroupsController::class, 'status']);
         Route::post('groups/{id}/config', [API\V4\GroupsController::class, 'setConfig']);
diff --git a/src/tests/Feature/Controller/FilesTest.php b/src/tests/Feature/Controller/FilesTest.php
new file mode 100644
--- /dev/null
+++ b/src/tests/Feature/Controller/FilesTest.php
@@ -0,0 +1,732 @@
+<?php
+
+namespace Tests\Feature\Controller;
+
+use App\Backends\Storage;
+use App\Fs\Item;
+use App\Fs\Property;
+use App\User;
+use Illuminate\Support\Facades\Storage as LaravelStorage;
+use Tests\TestCase;
+
+class FilesTest extends TestCase
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        Item::query()->delete();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function tearDown(): void
+    {
+        Item::query()->delete();
+
+        $disk = LaravelStorage::disk('files');
+        foreach ($disk->listContents('') as $dir) {
+            $disk->deleteDirectory($dir->path());
+        }
+
+        parent::tearDown();
+    }
+
+    /**
+     * Test deleting files (DELETE /api/v4/files/<file-id>)
+     */
+    public function testDelete(): void
+    {
+        $john = $this->getTestUser('john@kolab.org');
+        $jack = $this->getTestUser('jack@kolab.org');
+        $file = $this->getTestFile($john, 'teśt.txt', 'Teśt content');
+
+        // Unauth access
+        $response = $this->delete("api/v4/files/{$file->id}");
+        $response->assertStatus(401);
+
+        // Unauth access
+        $response = $this->actingAs($jack)->delete("api/v4/files/{$file->id}");
+        $response->assertStatus(403);
+
+        // Non-existing file
+        $response = $this->actingAs($john)->delete("api/v4/files/123");
+        $response->assertStatus(404);
+
+        // File owner access
+        $response = $this->actingAs($john)->delete("api/v4/files/{$file->id}");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File deleted successfully.", $json['message']);
+
+        // Test that the file has been removed from the filesystem?
+        $disk = LaravelStorage::disk('files');
+        $this->assertFalse($disk->directoryExists($file->path . '/' . $file->id));
+        $this->assertSame(null, Item::find($file->id));
+
+        // Test deletion of a chunked file
+        $file = $this->getTestFile($john, 'test.txt', ['T1', 'T2']);
+
+        $response = $this->actingAs($john)->delete("api/v4/files/{$file->id}");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File deleted successfully.", $json['message']);
+
+        // Test that the file has been removed from the filesystem?
+        $disk = LaravelStorage::disk('files');
+        $this->assertFalse($disk->directoryExists($file->path . '/' . $file->id));
+        $this->assertSame(null, Item::find($file->id));
+
+        // TODO: Test acting as another user with permissions
+    }
+
+    /**
+     * Test file downloads (GET /api/v4/files/downloads/<id>)
+     */
+    public function testDownload(): void
+    {
+        $john = $this->getTestUser('john@kolab.org');
+        $jack = $this->getTestUser('jack@kolab.org');
+        $file = $this->getTestFile($john, 'teśt.txt', 'Teśt content');
+
+        // Unauth access
+        $response = $this->get("api/v4/files/{$file->id}?downloadUrl=1");
+        $response->assertStatus(401);
+
+        $response = $this->actingAs($jack)->get("api/v4/files/{$file->id}?downloadUrl=1");
+        $response->assertStatus(403);
+
+        // Non-existing file
+        $response = $this->actingAs($john)->get("api/v4/files/123456?downloadUrl=1");
+        $response->assertStatus(404);
+
+        // Get downloadLink for the file
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}?downloadUrl=1");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame($file->id, $json['id']);
+        $link = $json['downloadUrl'];
+
+        // Fetch the file content
+        $response = $this->get(substr($link, strpos($link, '/api/') + 1));
+        $response->assertStatus(200)
+            ->assertHeader('Content-Disposition', "attachment; filename=test.txt; filename*=utf-8''te%C5%9Bt.txt")
+            ->assertHeader('Content-Length', $file->getProperty('size'))
+            ->assertHeader('Content-Type', $file->getProperty('mimetype') . '; charset=UTF-8');
+
+        $this->assertSame('Teśt content', $response->streamedContent());
+
+        // Test acting as another user with read permission
+        $permission = $this->getTestFilePermission($file, $jack, 'r');
+        $response = $this->actingAs($jack)->get("api/v4/files/{$permission->key}?downloadUrl=1");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame($file->id, $json['id']);
+        $link = $json['downloadUrl'];
+
+        // Fetch the file content
+        $response = $this->get(substr($link, strpos($link, '/api/') + 1));
+        $response->assertStatus(200)
+            ->assertHeader('Content-Disposition', "attachment; filename=test.txt; filename*=utf-8''te%C5%9Bt.txt")
+            ->assertHeader('Content-Length', $file->getProperty('size'))
+            ->assertHeader('Content-Type', $file->getProperty('mimetype') . '; charset=UTF-8');
+
+        $this->assertSame('Teśt content', $response->streamedContent());
+
+        // Test downloading a multi-chunk file
+        $file = $this->getTestFile($john, 'test2.txt', ['T1', 'T2']);
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}?downloadUrl=1");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame($file->id, $json['id']);
+        $link = $json['downloadUrl'];
+
+        // Fetch the file content
+        $response = $this->get(substr($link, strpos($link, '/api/') + 1));
+        $response->assertStatus(200)
+            ->assertHeader('Content-Disposition', "attachment; filename=test2.txt")
+            ->assertHeader('Content-Length', $file->getProperty('size'))
+            ->assertHeader('Content-Type', $file->getProperty('mimetype'));
+
+        $this->assertSame('T1T2', $response->streamedContent());
+    }
+
+    /**
+     * Test fetching/creating/updaing/deleting file permissions (GET|POST|PUT /api/v4/files/<file-id>/permissions)
+     */
+    public function testPermissions(): void
+    {
+        $john = $this->getTestUser('john@kolab.org');
+        $jack = $this->getTestUser('jack@kolab.org');
+        $file = $this->getTestFile($john, 'test1.txt', []);
+
+        // Unauth access not allowed
+        $response = $this->get("api/v4/files/{$file->id}/permissions");
+        $response->assertStatus(401);
+        $response = $this->post("api/v4/files/{$file->id}/permissions", []);
+        $response->assertStatus(401);
+
+        // Non-existing file
+        $response = $this->actingAs($john)->get("api/v4/files/1234/permissions");
+        $response->assertStatus(404);
+        $response = $this->actingAs($john)->post("api/v4/files/1234/permissions", []);
+        $response->assertStatus(404);
+
+        // No permissions to the file
+        $response = $this->actingAs($jack)->get("api/v4/files/{$file->id}/permissions");
+        $response->assertStatus(403);
+        $response = $this->actingAs($jack)->post("api/v4/files/{$file->id}/permissions", []);
+        $response->assertStatus(403);
+
+        // Expect an empty list of permissions
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}/permissions");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertCount(2, $json);
+        $this->assertSame([], $json['list']);
+        $this->assertSame(0, $json['count']);
+
+        // Empty input
+        $response = $this->actingAs($john)->post("api/v4/files/{$file->id}/permissions", []);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertCount(2, $json['errors']);
+        $this->assertSame(["The user field is required."], $json['errors']['user']);
+        $this->assertSame(["The permissions field is required."], $json['errors']['permissions']);
+
+        // Test more input validation
+        $post = ['user' => 'user', 'permissions' => 'read'];
+        $response = $this->actingAs($john)->post("api/v4/files/{$file->id}/permissions", $post);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertCount(2, $json['errors']);
+        $this->assertSame(["The user must be a valid email address."], $json['errors']['user']);
+        $this->assertSame("The file permission is invalid.", $json['errors']['permissions']);
+
+        // Let's add some permission
+        $post = ['user' => 'jack@kolab.org', 'permissions' => 'read-only'];
+        $response = $this->actingAs($john)->post("api/v4/files/{$file->id}/permissions", $post);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File permissions created successfully.", $json['message']);
+
+        $permission = $file->properties()->where('key', 'like', 'share-%')->orderBy('value')->first();
+
+        $this->assertSame("{$jack->email}:r", $permission->value);
+        $this->assertSame($permission->key, $json['id']);
+        $this->assertSame($jack->email, $json['user']);
+        $this->assertSame('read-only', $json['permissions']);
+        $this->assertSame(\App\Utils::serviceUrl('file/' . $permission->key), $json['link']);
+
+        // Error handling on use of the same user
+        $post = ['user' => 'jack@kolab.org', 'permissions' => 'read-only'];
+        $response = $this->actingAs($john)->post("api/v4/files/{$file->id}/permissions", $post);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame("File permission already exists.", $json['errors']['user']);
+
+        // Test update
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}/permissions/1234", $post);
+        $response->assertStatus(404);
+
+        $post = ['user' => 'jack@kolab.org', 'permissions' => 'read-write'];
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}/permissions/{$permission->key}", $post);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File permissions updated successfully.", $json['message']);
+
+        $permission->refresh();
+
+        $this->assertSame("{$jack->email}:rw", $permission->value);
+        $this->assertSame($permission->key, $json['id']);
+        $this->assertSame($jack->email, $json['user']);
+        $this->assertSame('read-write', $json['permissions']);
+        $this->assertSame(\App\Utils::serviceUrl('file/' . $permission->key), $json['link']);
+
+        // Input validation on update
+        $post = ['user' => 'jack@kolab.org', 'permissions' => 'read'];
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}/permissions/{$permission->key}", $post);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame("The file permission is invalid.", $json['errors']['permissions']);
+
+        // Test GET with existing permissions
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}/permissions");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertCount(2, $json);
+        $this->assertCount(1, $json['list']);
+        $this->assertSame(1, $json['count']);
+
+        $this->assertSame($permission->key, $json['list'][0]['id']);
+        $this->assertSame($jack->email, $json['list'][0]['user']);
+        $this->assertSame('read-write', $json['list'][0]['permissions']);
+        $this->assertSame(\App\Utils::serviceUrl('file/' . $permission->key), $json['list'][0]['link']);
+
+        // Delete permission
+        $response = $this->actingAs($john)->delete("api/v4/files/{$file->id}/permissions/1234");
+        $response->assertStatus(404);
+
+        $response = $this->actingAs($john)->delete("api/v4/files/{$file->id}/permissions/{$permission->key}");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File permissions deleted successfully.", $json['message']);
+
+        $this->assertCount(0, $file->properties()->where('key', 'like', 'share-%')->get());
+    }
+
+    /**
+     * Test fetching files/folders list (GET /api/v4/files)
+     */
+    public function testIndex(): void
+    {
+        // Unauth access not allowed
+        $response = $this->get("api/v4/files");
+        $response->assertStatus(401);
+
+        $user = $this->getTestUser('john@kolab.org');
+
+        // Expect an empty list
+        $response = $this->actingAs($user)->get("api/v4/files");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertCount(3, $json);
+        $this->assertSame([], $json['list']);
+        $this->assertSame(0, $json['count']);
+        $this->assertSame(false, $json['hasMore']);
+
+        // Create some files and test again
+        $file1 = $this->getTestFile($user, 'test1.txt', [], ['mimetype' => 'text/plain', 'size' => 12345]);
+        $file2 = $this->getTestFile($user, 'test2.gif', [], ['mimetype' => 'image/gif', 'size' => 10000]);
+
+        $response = $this->actingAs($user)->get("api/v4/files");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertCount(3, $json);
+        $this->assertSame(2, $json['count']);
+        $this->assertSame(false, $json['hasMore']);
+        $this->assertCount(2, $json['list']);
+        $this->assertSame('test1.txt', $json['list'][0]['name']);
+        $this->assertSame($file1->id, $json['list'][0]['id']);
+        $this->assertSame('test2.gif', $json['list'][1]['name']);
+        $this->assertSame($file2->id, $json['list'][1]['id']);
+
+        // Searching
+        $response = $this->actingAs($user)->get("api/v4/files?search=t2");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertCount(3, $json);
+        $this->assertSame(1, $json['count']);
+        $this->assertSame(false, $json['hasMore']);
+        $this->assertCount(1, $json['list']);
+        $this->assertSame('test2.gif', $json['list'][0]['name']);
+        $this->assertSame($file2->id, $json['list'][0]['id']);
+
+        // TODO: Test paging
+    }
+
+    /**
+     * Test fetching file metadata (GET /api/v4/files/<file-id>)
+     */
+    public function testShow(): void
+    {
+        // Unauth access not allowed
+        $response = $this->get("api/v4/files/1234");
+        $response->assertStatus(401);
+
+        $john = $this->getTestUser('john@kolab.org');
+        $jack = $this->getTestUser('jack@kolab.org');
+        $file = $this->getTestFile($john, 'teśt.txt', 'Teśt content');
+
+        // Non-existing file
+        $response = $this->actingAs($jack)->get("api/v4/files/1234");
+        $response->assertStatus(404);
+
+        // Unauthorized access
+        $response = $this->actingAs($jack)->get("api/v4/files/{$file->id}");
+        $response->assertStatus(403);
+
+        // Get file metadata
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame($file->id, $json['id']);
+        $this->assertSame($file->getProperty('mimetype'), $json['mimetype']);
+        $this->assertSame((int) $file->getProperty('size'), $json['size']);
+        $this->assertSame($file->getProperty('name'), $json['name']);
+        $this->assertSame(true, $json['isOwner']);
+        $this->assertSame(true, $json['canUpdate']);
+        $this->assertSame(true, $json['canDelete']);
+
+        // Get file content
+        $response = $this->actingAs($john)->get("api/v4/files/{$file->id}?download=1");
+        $response->assertStatus(200)
+            ->assertHeader('Content-Disposition', "attachment; filename=test.txt; filename*=utf-8''te%C5%9Bt.txt")
+            ->assertHeader('Content-Length', $file->getProperty('size'))
+            ->assertHeader('Content-Type', $file->getProperty('mimetype') . '; charset=UTF-8');
+
+        $this->assertSame('Teśt content', $response->streamedContent());
+
+        // Test acting as a user with file permissions
+        $permission = $this->getTestFilePermission($file, $jack, 'r');
+        $response = $this->actingAs($jack)->get("api/v4/files/{$permission->key}");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame($file->id, $json['id']);
+        $this->assertSame(false, $json['isOwner']);
+        $this->assertSame(false, $json['canUpdate']);
+        $this->assertSame(false, $json['canDelete']);
+    }
+
+    /**
+     * Test creating files (POST /api/v4/files)
+     */
+    public function testStore(): void
+    {
+        // Unauth access not allowed
+        $response = $this->post("api/v4/files");
+        $response->assertStatus(401);
+
+        $john = $this->getTestUser('john@kolab.org');
+
+        // Test input validation
+        $response = $this->sendRawBody($john, 'POST', "api/v4/files", [], '');
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame(["The name field is required."], $json['errors']['name']);
+
+        $response = $this->sendRawBody($john, 'POST', "api/v4/files?name=*.txt", [], '');
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame(["The file name is invalid."], $json['errors']['name']);
+
+        // Create a file - the simple method
+        $body = "test content";
+        $headers = [];
+        $response = $this->sendRawBody($john, 'POST', "api/v4/files?name=test.txt", $headers, $body);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File created successfully.", $json['message']);
+        $this->assertSame('text/plain', $json['mimetype']);
+        $this->assertSame(strlen($body), $json['size']);
+        $this->assertSame('test.txt', $json['name']);
+
+        $file = Item::find($json['id']);
+
+        $this->assertSame(Item::TYPE_FILE, $file->type);
+        $this->assertSame($json['mimetype'], $file->getProperty('mimetype'));
+        $this->assertSame($json['size'], (int) $file->getProperty('size'));
+        $this->assertSame($json['name'], $file->getProperty('name'));
+        $this->assertSame($body, $this->getTestFileContent($file));
+    }
+
+    /**
+     * Test creating files - resumable (POST /api/v4/files)
+     */
+    public function testStoreResumable(): void
+    {
+        $john = $this->getTestUser('john@kolab.org');
+
+        $response = $this->actingAs($john)->post("api/v4/files?name=test2.txt&media=resumable&size=400");
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame(0, $json['uploaded']);
+        $this->assertMatchesRegularExpression(
+            '/^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/',
+            $json['uploadId']
+        );
+
+        $uploadId = $json['uploadId'];
+        $size = 0;
+        $fileContent = '';
+
+        for ($x = 0; $x <= 2; $x++) {
+            $body = str_repeat("$x", 100);
+            $response = $this->sendRawBody(null, 'POST', "api/v4/files/uploads/{$uploadId}?from={$size}", [], $body);
+            $response->assertStatus(200);
+
+            $json = $response->json();
+            $size += 100;
+            $fileContent .= $body;
+
+            $this->assertSame($size, $json['uploaded']);
+            $this->assertSame($uploadId, $json['uploadId']);
+        }
+
+        $body = str_repeat("$x", 100);
+        $response = $this->sendRawBody(null, 'POST', "api/v4/files/uploads/{$uploadId}?from={$size}", [], $body);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+        $size += 100;
+        $fileContent .= $body;
+
+        $this->assertSame('success', $json['status']);
+        // $this->assertSame("", $json['message']);
+        $this->assertSame('text/plain', $json['mimetype']);
+        $this->assertSame($size, $json['size']);
+        $this->assertSame('test2.txt', $json['name']);
+
+        $file = Item::find($json['id']);
+
+        $this->assertSame(Item::TYPE_FILE, $file->type);
+        $this->assertSame($json['mimetype'], $file->getProperty('mimetype'));
+        $this->assertSame($json['size'], (int) $file->getProperty('size'));
+        $this->assertSame($json['name'], $file->getProperty('name'));
+        $this->assertSame($fileContent, $this->getTestFileContent($file));
+    }
+
+    /**
+     * Test updating files (PUT /api/v4/files/<file-id>)
+     */
+    public function testUpdate(): void
+    {
+        // Unauth access not allowed
+        $response = $this->put("api/v4/files/1234");
+        $response->assertStatus(401);
+
+        $john = $this->getTestUser('john@kolab.org');
+        $jack = $this->getTestUser('jack@kolab.org');
+        $file = $this->getTestFile($john, 'teśt.txt', 'Teśt content');
+
+        // Non-existing file
+        $response = $this->actingAs($john)->put("api/v4/files/1234", []);
+        $response->assertStatus(404);
+
+        // Unauthorized access
+        $response = $this->actingAs($jack)->put("api/v4/files/{$file->id}", []);
+        $response->assertStatus(403);
+
+        // Test name validation
+        $post = ['name' => 'test/test.txt'];
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}", $post);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame(["The file name is invalid."], $json['errors']['name']);
+
+        $post = ['name' => 'new name.txt', 'media' => 'test'];
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}", $post);
+        $response->assertStatus(422);
+
+        $json = $response->json();
+
+        $this->assertSame('error', $json['status']);
+        $this->assertSame("The specified media is invalid.", $json['errors']['media']);
+
+        // Rename a file
+        $post = ['name' => 'new namś.txt'];
+        $response = $this->actingAs($john)->put("api/v4/files/{$file->id}", $post);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File updated successfully.", $json['message']);
+
+        $file->refresh();
+
+        $this->assertSame($post['name'], $file->getProperty('name'));
+
+        // Update file content
+        $body = "Test1\nTest2";
+        $response = $this->sendRawBody($john, 'PUT', "api/v4/files/{$file->id}?media=content", [], $body);
+        $response->assertStatus(200);
+
+        $json = $response->json();
+
+        $this->assertSame('success', $json['status']);
+        $this->assertSame("File updated successfully.", $json['message']);
+
+        $file->refresh();
+
+        $this->assertSame($body, $this->getTestFileContent($file));
+        $this->assertSame('text/plain', $file->getProperty('mimetype'));
+        $this->assertSame(strlen($body), (int) $file->getProperty('size'));
+
+        // TODO: Test acting as another user with file permissions
+        // TODO: Test media=resumable
+    }
+
+    /**
+     * Create a test file.
+     *
+     * @param \App\User    $user    File owner
+     * @param string       $name    File name
+     * @param string|array $content File content
+     * @param array        $props   Extra file properties
+     *
+     * @return \App\Fs\Item
+     */
+    protected function getTestFile(User $user, string $name, $content = [], $props = []): Item
+    {
+        $disk = LaravelStorage::disk('files');
+
+        $file = $user->fsItems()->create(['type' => Item::TYPE_FILE]);
+        $size = 0;
+        $mimetype = '';
+
+        if (is_array($content) && empty($content)) {
+            // do nothing, we don't need the body here
+        } else {
+            foreach ((array) $content as $idx => $chunk) {
+                $chunkId = \App\Utils::uuidStr();
+                $path = Storage::chunkLocation($chunkId, $file);
+
+                $disk->write($path, $chunk);
+
+                if (!$size) {
+                    $mimetype = $disk->mimeType($path);
+                }
+
+                $size += strlen($chunk);
+
+                $file->chunks()->create([
+                        'chunk_id' => $chunkId,
+                        'sequence' => $idx,
+                        'size' => strlen($chunk),
+                ]);
+            }
+        }
+
+        $properties = [
+            'name' => $name,
+            'size' => $size,
+            'mimetype' => $mimetype ?: 'application/octet-stream',
+        ];
+
+        $file->setProperties($props + $properties);
+
+        return $file;
+    }
+
+    /**
+     * Get contents of a test file.
+     *
+     * @param \App\Fs\Item $file File record
+     *
+     * @return string
+     */
+    protected function getTestFileContent(Item $file): string
+    {
+        $content = '';
+
+        $file->chunks()->orderBy('sequence')->get()->each(function ($chunk) use ($file, &$content) {
+            $disk = LaravelStorage::disk('files');
+            $path = Storage::chunkLocation($chunk->chunk_id, $file);
+
+            $content .= $disk->read($path);
+        });
+
+        return $content;
+    }
+
+    /**
+     * Create a test file permission.
+     *
+     * @param \App\Fs\Item $file       The file
+     * @param \App\User    $user       File owner
+     * @param string       $permission File permission
+     *
+     * @return \App\Fs\Property File permission property
+     */
+    protected function getTestFilePermission(Item $file, User $user, string $permission): Property
+    {
+        $shareId = 'share-' . \App\Utils::uuidStr();
+
+        return $file->properties()->create([
+                'key' => $shareId,
+                'value' => "{$user->email}:{$permission}",
+        ]);
+    }
+
+    /**
+     * Invoke a HTTP request with a custom raw body
+     *
+     * @param ?\App\User $user    Authenticated user
+     * @param string     $method  Request method (POST,  PUT)
+     * @param string     $uri     Request URL
+     * @param array      $headers Request headers
+     * @param string     $content Raw body content
+     *
+     * @return \Illuminate\Testing\TestResponse HTTP Response object
+     */
+    protected function sendRawBody(?User $user, string $method, string $uri, array $headers, string $content)
+    {
+        $headers['Content-Length'] = strlen($content);
+
+        $server = $this->transformHeadersToServerVars($headers);
+        $cookies = $this->prepareCookiesForRequest();
+
+        if ($user) {
+            return $this->actingAs($user)->call($method, $uri, [], $cookies, [], $server, $content);
+        } else {
+            // TODO: Make sure this does not use "acting user" set earlier
+            return $this->call($method, $uri, [], $cookies, [], $server, $content);
+        }
+    }
+}