---
title: "Session data"
manual: "TYPO3 Explained"
version: "main"
permalink: "https://docs.typo3.org/permalink/t3coreapi:session-data@main"
source: "ApiOverview/Authentication/Sessions/SessionData.rst"
rendered: "2026-09-24T12:36:55+00:00"
---

# Session data {#session-data}

In the TYPO3 frontend, data can be stored in the current user session.

The actual location where the data will be stored is determined by the
[Session storage configuration](https://docs.typo3.org/permalink/t3coreapi:session-storage@main).

You can use the following methods in
`\TYPO3\CMS\Frontend\Authentication\FrontendUserAuthentication`:

-   **`FrontendUserAuthentication::getKey($type, $key)`**

    Loads data from the session.

-   **`FrontendUserAuthentication::setKey($type, $key, $data)`**

    Saves data to the session as a string.

-   **`FrontendUserAuthentication::storeSessionData()`**

    Writes session data so it is available in the next request.

## Example: save shopping basket into user session {#session-data-example-multi-step}

Let us assume we have an Extbase Controller for a shopping basket. We want to
preserve the data the user enters before closing the browser
window. This should also work for non logged-in users.

We can use `$this->request->getAttribute('frontend.user')`
to create a frontend user on the fly if none exists.

If no [Frontend user](https://docs.typo3.org/permalink/t3coreapi:frontend-user-api@main)
is currently logged in, an anonymous frontend user will be created on the fly.

In the browser of the current user a session cookie will be set linking
them to the anonymous frontend user.

**packages/my_extension/Classes/Controller/ShoppingCartController.php**

```php
<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Controller;

use MyVendor\MyExtension\Domain\Model\Cart;
use MyVendor\MyExtension\Domain\Model\Item;
use Psr\Http\Message\ResponseInterface;
use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
use TYPO3\CMS\Frontend\Authentication\FrontendUserAuthentication;

class ShoppingCartController extends ActionController
{
  public const FORM_SESSION = 'myextension_cart';

  public function putItemAction(Item $item): ResponseInterface
  {
    // Fetch cart from session or create a new one
    $cart = $this->getCartFromSession() ?? new Cart();
    $cart->add($item);
    $this->storeCartInSession($cart);
    return $this->redirect('list');
  }

  public function listAction(): ResponseInterface
  {
    $this->view->assign('cart', $this->getCartFromSession());
    return $this->htmlResponse();
  }

  private function getFrontendUser(): FrontendUserAuthentication
  {
    // This will create an anonymous frontend user if none is logged in
    return $this->request->getAttribute('frontend.user');
  }

  private function storeCartInSession(Cart $cart): void
  {
    // We use type ses to store the data in the session
    $this->getFrontendUser()->setKey('ses', self::FORM_SESSION, serialize($cart));
    // Important: store session data! Or it is not available in the next request!
    $this->getFrontendUser()->storeSessionData();
  }

  private function getCartFromSession(): ?Cart
  {
    $data = $this->getFrontendUser()->getKey('ses', self::FORM_SESSION);
    if (is_string($data)) {
      $cart = unserialize($data);
      if ($cart instanceof Cart) {
        return $cart;
      }
    }
    return null;
  }
}

```