BootCompletedEvent 

Example 

Registration of the event listener in the extension's Services.yaml:

services:
  # Place here the default dependency injection configuration

  MyVendor\MyExtension\Bootstrap\EventListener\MyEventListener:
    tags:
      - name: event.listener
        identifier: 'my-extension/boot-completed'

Read how to configure dependency injection in extensions.

An implementation of the event listener:

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\Bootstrap\EventListener;

use TYPO3\CMS\Core\Core\Event\BootCompletedEvent;

final class MyEventListener
{
    public function __invoke(BootCompletedEvent $e): void
    {
        // Do your magic
    }
}

API 

class BootCompletedEvent

Fully qualified name

\TYPO3\CMS\Core\Core\Event\BootCompletedEvent

Executed when TYPO3 has fully booted (after all ext_tables.php files have been processed)

isCachingEnabled ( )

Returns

bool