diff --git a/apps/files_sharing/lib/Controller/ShareesAPIController.php b/apps/files_sharing/lib/Controller/ShareesAPIController.php
index 742962e649..d25f24f6f7 100644
--- a/apps/files_sharing/lib/Controller/ShareesAPIController.php
+++ b/apps/files_sharing/lib/Controller/ShareesAPIController.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *
@@ -90,7 +91,7 @@ class ShareesAPIController extends OCSController {
 	 * @param ISearch $collaboratorSearch
 	 */
 	public function __construct(
-		$appName,
+		string $appName,
 		IRequest $request,
 		IConfig $config,
 		IURLGenerator $urlGenerator,
@@ -117,7 +118,7 @@ class ShareesAPIController extends OCSController {
 	 * @return DataResponse
 	 * @throws OCSBadRequestException
 	 */
-	public function search($search = '', $itemType = null, $page = 1, $perPage = 200, $shareType = null, $lookup = true) {
+	public function search(string $search = '', string $itemType = null, int $page = 1, int $perPage = 200, $shareType = null, bool $lookup = true): DataResponse {
 
 		// only search for string larger than a given threshold
 		$threshold = (int)$this->config->getSystemValue('sharing.minSearchStringLength', 0);
@@ -205,7 +206,7 @@ class ShareesAPIController extends OCSController {
 	 * @param string $itemType
 	 * @return bool
 	 */
-	protected function isRemoteSharingAllowed($itemType) {
+	protected function isRemoteSharingAllowed(string $itemType): bool {
 		try {
 			// FIXME: static foo makes unit testing unnecessarily difficult
 			$backend = \OC\Share\Share::getBackend($itemType);
@@ -223,7 +224,7 @@ class ShareesAPIController extends OCSController {
 	 * @param array $params Parameters for the URL
 	 * @return string
 	 */
-	protected function getPaginationLink($page, array $params) {
+	protected function getPaginationLink(int $page, array $params): string {
 		if ($this->isV2()) {
 			$url = $this->urlGenerator->getAbsoluteURL('/ocs/v2.php/apps/files_sharing/api/v1/sharees') . '?';
 		} else {
@@ -236,7 +237,7 @@ class ShareesAPIController extends OCSController {
 	/**
 	 * @return bool
 	 */
-	protected function isV2() {
+	protected function isV2(): bool {
 		return $this->request->getScriptName() === '/ocs/v2.php';
 	}
 }