---
title: "Backend login form API"
manual: "TYPO3 Explained"
version: "13.4"
permalink: "https://docs.typo3.org/permalink/t3coreapi:login-provider@13.4"
source: "ApiOverview/Backend/LoginProvider.rst"
rendered: "2026-10-05T17:28:20+00:00"
---

# Backend login form API {#login-provider}

## Registering a login provider {#login-provider-registration}

The concept of the backend login is based on "login providers".

A login provider can be registered within your `config/system/settings.php`
or `config/system/additional.php`  like this:

**config/system/additional.php | typo3conf/system/additional.php**

```php
$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['backend']['loginProviders'][1433416020] = [
    'provider' => \MyVendor\MyExtension\LoginProvider\CustomLoginProvider::class,
    'sorting' => 50,
    'iconIdentifier' => 'actions-key',
    'label' => 'LLL:EXT:backend/Resources/Private/Language/locallang.xlf:login.link'
];
```

The settings are defined as:

-   **`provider`**

    The login provider class name, which must implement
    `\TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface`.

-   **`sorting`**

    The sorting is important for the ordering of the links to the possible
    login providers on the login screen.

-   **`iconIdentifier`**

    Accepts any icon identifier that is available in the Icon Registry.

-   **`label`**

    The label for the login provider link on the login screen.

For a new login provider you have to register a **new key** \- by best practice
the current unix timestamp - in
`$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['backend']['loginProviders']`.

If your login provider extends another one, you may only overwrite necessary
settings. An example would be to extend an existing provider and
replace its registered `provider` class with your custom class.

**config/system/additional.php | typo3conf/system/additional.php**

```php
$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['backend']['loginProviders'][1433416020]['provider'] =
    \MyVendor\MyExtension\LoginProvider\CustomProviderExtendingUsernamePasswordLoginProvider::class
```

## LoginProviderInterface {#login-provider-interface}

<!-- TODO: no Markdown rendering for "deprecated" -->

Method LoginProviderInterface->render() has been marked as deprecated
and is substituted by  LoginProviderInterface->modifyView() that will
be added to the interface in TYPO3 v14, removing render() from the
interface in v14. See section Migration.

The `\TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface` contains
only the deprecated `render()` method in TYPO3 v13.

-   **interface LoginProviderInterface**

    -   *Fully qualified name:* `\TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface`

    Interface for Backend Login providers

    -   **render(\\TYPO3\\CMS\\Fluid\\View\\StandaloneView $view, \\TYPO3\\CMS\\Core\\Page\\PageRenderer $pageRenderer, \\TYPO3\\CMS\\Backend\\Controller\\LoginController $loginController)**

        Render the login HTML

        Implement this method and set the template for your form.
        This is also the right place to assign data to the view
        and add necessary JavaScript resources to the page renderer.

        A good example is EXT:openid

        -   **Example:**

            $view->setTemplatePathAndFilename($pathAndFilename);
            $view->assign('foo', 'bar');

        -   *param $view:* the view
        -   *param $pageRenderer:* the pageRenderer
        -   *param $loginController:* the loginController

### Migration {#login-provider-interface-migration}

Consumers of `\TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface`
should implement the `modifyView()` method and and retain a stub for the
`render()` method to satisfy the interface. See the example below.

The transition should be smooth. Consumers that need
`\TYPO3\CMS\Core\Page\PageRenderer` for JavaScript magic, should use
[dependency injection](https://docs.typo3.org/permalink/t3coreapi:dependency-injection@13.4) to receive an instance
of it.

An implementation of `\TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface` could
look like this for TYPO3 v13:

**EXT:my_extension/Classes/Login/MyLoginProvider.php**

```php
<?php

namespace MyVendor\MyExtension\Login;

use Psr\Http\Message\ServerRequestInterface;
use Symfony\Component\DependencyInjection\Attribute\Autoconfigure;
use TYPO3\CMS\Backend\Controller\LoginController;
use TYPO3\CMS\Backend\LoginProvider\LoginProviderInterface;
use TYPO3\CMS\Core\Page\PageRenderer;
use TYPO3\CMS\Core\View\ViewInterface;
use TYPO3\CMS\Fluid\View\FluidViewAdapter;
use TYPO3\CMS\Fluid\View\StandaloneView;

#[Autoconfigure(public: true)]
final readonly class MyLoginProvider implements LoginProviderInterface
{
  public function __construct(
    private PageRenderer $pageRenderer,
  ) {}

  /**
   * todo: Remove when dropping TYPO3 v13 support
   * @deprecated Remove in v14 when method is removed from LoginProviderInterface
   */
  public function render(StandaloneView $view, PageRenderer $pageRenderer, LoginController $loginController)
  {
    throw new \RuntimeException('Legacy interface implementation. Should not be called', 123456789);
  }

  public function modifyView(ServerRequestInterface $request, ViewInterface $view): string
  {
    $this->pageRenderer->addJsFile('someFile');
    // Custom login provider implementations can add custom fluid lookup paths.
    if ($view instanceof FluidViewAdapter) {
      $templatePaths = $view->getRenderingContext()->getTemplatePaths();
      $templateRootPaths = $templatePaths->getTemplateRootPaths();
      $templateRootPaths[] = 'EXT:my_extension/Resources/Private/Templates';
      $templatePaths->setTemplateRootPaths($templateRootPaths);
    }
    $view->assign('Some Variable', 'some value');
    return 'Login/MyLoginForm';
  }
}

```

The default implementation in `\TYPO3\CMS\Backend\LoginProvider\UsernamePasswordLoginProvider`
is a good example. Extensions that need to configure additional template, layout or
partial lookup paths can extend them, see lines 23-28 in the example above.

Consumers of `\TYPO3\CMS\Backend\LoginProvider\Event\ModifyPageLayoutOnLoginProviderSelectionEvent`
should use the request instead, and/or should get an instance of
`\TYPO3\CMS\Core\Page\PageRenderer` injected as well.

## The view {#login-provider-view}

<!-- TODO: no Markdown rendering for "deprecated" -->

Method LoginProviderInterface->render() has been marked as deprecated
and is substituted by  LoginProviderInterface->modifyView() that will
be added to the interface in TYPO3 v14, removing render() from the
interface in v14. See section Migration.

The name of the template must be returned by the `modifyView()` method of the
login provider. Variables can be assigned to the view supplied as
second parameter.

The template file must only contain the form fields, not the form-tag.
Later on, the view renders the complete login screen.

View requirements:

-   The template must use the `Login`-layout provided by the
    Core `<f:layout name="Login">`.
-   Form fields must be provided within the section
    `<f:section name="loginFormFields">`.

**EXT:my_sitepackage/Resources/Private/Templates/MyLoginForm.html**

```html
<f:layout name="Login" />
<f:section name="loginFormFields">
  <div class="form-group t3js-login-openid-section" id="t3-login-openid_url-section">
    <div class="input-group">
      <input
        type="text"
        id="openid_url"
        name="openid_url"
        value="{presetOpenId}"
        autofocus="autofocus"
        placeholder="{f:translate(key: 'openId', extensionName: 'openid')}"
        class="form-control input-login t3js-clearable t3js-login-openid-field"
      >
      <div class="input-group-addon">
        <span class="fa fa-openid"></span>
      </div>
    </div>
  </div>
</f:section>

```

## Examples {#login-provider-examples}

Within the Core you can find the standard implementation in the system extension
`backend`:

See class [EXT:backend/Classes/LoginProvider/UsernamePasswordLoginProvider.php (GitHub)](https://github.com/typo3/typo3/blob/13.4/typo3/sysext/backend/Classes/LoginProvider/UsernamePasswordLoginProvider.php)
with its template [EXT:backend/Resources/Private/Templates/Login/UserPassLoginForm.html (GitHub)](https://github.com/typo3/typo3/blob/13.4/typo3/sysext/backend/Resources/Private/Templates/Login/UserPassLoginForm.html).