Attention

TYPO3 v8 has reached its end-of-life March 31st, 2020 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.

There is no further ELTS support. It is recommended that you upgrade your project and use a supported version of TYPO3.

Routing

Each request to the backend is eventually executed by a controller. A list of routes is defined which maps a given request to a controller and an action.

Routes are defined inside extensions, in file Configuration/Backend/Routes.php for general requests and in Configuration/Backend/AjaxRoutes.php for AJAX calls.

Here is an extract of typo3/sysext/backend/Configuration/Backend/Routes.php:

<?php
use TYPO3\CMS\Backend\Controller;

/**
 * Definitions for routes provided by EXT:backend
 * Contains all "regular" routes for entry points
 *
 * Please note that this setup is preliminary until all core use-cases are set up here.
 * Especially some more properties regarding modules will be added until TYPO3 CMS 7 LTS, and might change.
 *
 * Currently the "access" property is only used so no token creation + validation is made,
 * but will be extended further.
 */
return [
        // Login screen of the TYPO3 Backend
        'login' => [
                'path' => '/login',
                'access' => 'public',
                'target' => Controller\LoginController::class . '::formAction'
        ],

        // Main backend rendering setup (previously called backend.php) for the TYPO3 Backend
        'main' => [
                'path' => '/main',
                'target' => Controller\BackendController::class . '::mainAction'
        ],
        // ...
];

So a routes file essentially returns an array containing routes mapping. A route is defined by a key, a path and a target. The "public" access property indicates that no authentication is required for that action.

Note

As the above code extract mentions, routes are a new feature (since TYPO3 CMS 7) and may yet evolve.