template.php

<?php
# src/Command/SendTemplateMailCommand.php
# php bin/console app:send-template-mail

namespace App\Command;

use Mailtrap\Helper\ResponseHelper;
use Mailtrap\MailtrapClient;
use Mailtrap\Mime\MailtrapEmail;
use Symfony\Component\Console\Attribute\AsCommand;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Mime\Address;

#[AsCommand(name: 'app:send-template-mail')]
final class SendTemplateMailCommand
{
    public function __invoke(): int { // Available since Symfony 7.0. For earlier versions, use the execute() method instead.
        $email = (new MailtrapEmail())
            ->from(new Address('example@YOUR-DOMAIN-HERE.com', 'Mailtrap Template')) // <--- you should use your domain here that you installed in the mailtrap.io admin area (otherwise you will get 401)
            ->replyTo(new Address('reply@YOUR-DOMAIN-HERE.com'))
            ->to(new Address('example@gmail.com', 'Jon'))
            // when using a template, you should not set a subject, text, HTML, category
            // otherwise there will be a validation error from the API side
            ->templateUuid('bfa432fd-0000-0000-0000-8493da283a69')
            ->templateVariables([
                'user_name' => 'Jon Bush',
                'next_step_link' => 'https://mailtrap.io/',
                'get_started_link' => 'https://mailtrap.io/',
                'onboarding_video_link' => 'some_video_link',
                'company' => [
                    'name' => 'Best Company',
                    'address' => 'Its Address',
                ],
                'products' => [
                    [
                        'name' => 'Product 1',
                        'price' => 100,
                    ],
                    [
                        'name' => 'Product 2',
                        'price' => 200,
                    ],
                ],
                'isBool' => true,
                'int' => 123
            ])
        ;

        $response = MailtrapClient::initSendingEmails(
            apiKey: $_ENV['MAILTRAP_API_KEY'] // your API token from here https://mailtrap.io/api-tokens
        )->send($email);

        var_dump(ResponseHelper::toArray($response));

        return Command::SUCCESS;
    }
}