Craft CMS Ngrok w/ Docker

readme.md

Ensure your site URL's use @web (I know it's not recommended, but that's the only way I could get it to work). Change it back to $DEFAULT_SITE_URL (or whatever you had before) for production.

command.sh

ngrok http dev.example.com:443 -host-header=dev.example.com -region=eu

general.php

<?php

$isNgrok = array_key_exists('HTTP_X_ORIGINAL_HOST', $_SERVER) && strpos($_SERVER['HTTP_X_ORIGINAL_HOST'], 'ngrok');
$host    = $isNgrok ? ('https://' . $_SERVER['HTTP_X_ORIGINAL_HOST'] . '/') : getenv('DEFAULT_SITE_URL');

return [
	'*' => [
		'siteUrl' => $host,
		'aliases' => [
	    	'web' => $host,
	    ],
	],
];