diff --git a/changelog/unreleased/bugfix-oc10-index-route b/changelog/unreleased/bugfix-oc10-index-route
new file mode 100644
index 00000000000..42a53961e06
--- /dev/null
+++ b/changelog/unreleased/bugfix-oc10-index-route
@@ -0,0 +1,8 @@
+Bugfix: Add index route for the OC10 integration
+
+Added an index route for the OC10 integration which gets called when opening http://your-server/index.php/apps/web.
+The route basically redirects to the same URL while appending /index.html, as this is the correct URL for
+accessing the Web UI. Setting Web as default layout would result in an endless redirect loop otherwise.
+
+https://github.com/owncloud/web/pull/5201
+https://github.com/owncloud/core/issues/38799
diff --git a/packages/web-integration-oc10/appinfo/routes.php b/packages/web-integration-oc10/appinfo/routes.php
index 7e45ea9aeef..b64b62ae9f0 100644
--- a/packages/web-integration-oc10/appinfo/routes.php
+++ b/packages/web-integration-oc10/appinfo/routes.php
@@ -26,7 +26,8 @@
     $this,
     [
         'routes' => [
-			['name' => 'Config#getConfig', 'url' => '/config.json', 'verb' => 'GET'],
+            ['name' => 'Index#index', 'url' => '/', 'verb' => 'GET'],
+            ['name' => 'Config#getConfig', 'url' => '/config.json', 'verb' => 'GET'],
             [
             	'name' => 'Files#getFile',
 				'url' => '/{path}',
diff --git a/packages/web-integration-oc10/lib/Controller/IndexController.php b/packages/web-integration-oc10/lib/Controller/IndexController.php
new file mode 100644
index 00000000000..b6a46087161
--- /dev/null
+++ b/packages/web-integration-oc10/lib/Controller/IndexController.php
@@ -0,0 +1,92 @@
+<?php
+/**
+ * @author Jannik Stehle <jstehle@owncloud.com>
+ * @author Jan Ackermann <jackermann@owncloud.com>
+ *
+ * @copyright Copyright (c) 2021, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Web\Controller;
+
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http\RedirectResponse;
+use OCP\AppFramework\Http\Response;
+use OCP\AppFramework\Http\TemplateResponse;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\IRequest;
+
+/**
+ * Class IndexController
+ *
+ * @package OCA\Web\Controller
+ */
+class IndexController extends Controller {
+
+    /**
+     * @var IConfig
+     */
+    private $config;
+    /**
+     * @var IL10N
+     */
+    private $l10n;
+
+    /**
+     * IndexController constructor.
+     *
+     * @param string $appName
+     * @param IRequest $request
+     * @param IConfig $config
+     * @param IL10N $l10n
+     */
+    public function __construct(string $appName, IRequest $request, IConfig $config, IL10N $l10n) {
+        parent::__construct($appName, $request);
+        $this->config = $config;
+        $this->l10n = $l10n;
+    }
+
+    /**
+     * Loads the WebUI index page according to the web.baseUrl config.
+     * Then appends "/index.html" to the URL as this is needed to load the page properly.
+     *
+     * @PublicPage
+     * @NoCSRFRequired
+     *
+     * @return RedirectResponse | TemplateResponse
+     */
+    public function index(): Response {
+        $webBaseUrl = $this->config->getSystemValue('web.baseUrl', null);
+        if (!$webBaseUrl) {
+            // Check the old phoenix.baseUrl system key to provide compatibility across
+            // the name change from phoenix to web.
+            $webBaseUrl = \OC::$server->getConfig()->getSystemValue('phoenix.baseUrl', null);
+        }
+
+        if ($webBaseUrl) {
+            $webBaseUrl = \rtrim($webBaseUrl, '/') . '/index.html';
+            return new RedirectResponse($webBaseUrl);
+        }
+
+        return new TemplateResponse(
+            'core', 'error',
+            [
+                "errors" => [["error" => $this->l10n->t('Unable to reach the WebURL. Please contact your administrator.')]]
+            ], 'guest'
+        );
+    }
+}