SendGrid PHP API

$ composer require sendgrid/sendgrid

<?php

namespace App\Controllers;

use Exception;
use SendGrid;
use SendGrid\Mail\Mail;
use SendGrid\Mail\Personalization;
use SendGrid\Mail\To;

class SendGridController extends BaseController
{
    private const API_KEY = '';
    private const TEMPLATE_ID = '';

    public function send()
    {
        $email = new Mail();
        try {
            $email->setFrom('from@example.com', 'From Name');
            $email->setTemplateId(self::TEMPLATE_ID);
            $email->addTo('to@example.com');
            $email->addDynamicTemplateData('value1', 'foo');
            $email->addDynamicTemplateData('value2', 'bar');
            $email->addDynamicTemplateData('value3', 'baz');
        } catch (SendGrid\Mail\TypeException $e) {
            die('Caught exception: ' . $e->getMessage());
        }

        $sendgrid = new SendGrid(self::API_KEY);
        try {
            $response = $sendgrid->send($email);
            echo "<pre>";
            echo $response->statusCode() . "\n";
            print_r($response->headers());
            echo $response->body() . "\n";
            echo "</pre>";
        } catch (Exception $e) {
            die('Caught exception: ' . $e->getMessage());
        }
    }

    public function bulkSend()
    {
        $email = new Mail();
        try {
            $email->setFrom('from@example.com', 'From Name');
            $email->setTemplateId(self::TEMPLATE_ID);
            $users = [
                [
                    'email_address' => 'to1@example.com',
                    'value1'        => 'foo1',
                    'value2'        => 'foo2',
                    'value3'        => 'foo3',
                ],
                [
                    'email_address' => 'to2@example.com',
                    'value1'        => 'bar1',
                    'value2'        => 'bar2',
                    'value3'        => 'bar3',
                ],
                [
                    'email_address' => 'to3@example.com',
                    'value1'        => 'baz1',
                    'value2'        => 'baz2',
                    'value3'        => 'baz3',
                ],
            ];
            foreach ($users as $user) {
                $personalization = new Personalization();
                $personalization->addTo(new To($user['email_address']));
                $personalization->addDynamicTemplateData('value1', $user['value1']);
                $personalization->addDynamicTemplateData('value2', $user['value2']);
                $personalization->addDynamicTemplateData('value3', $user['value3']);
                $email->addPersonalization($personalization);
            }
        } catch (SendGrid\Mail\TypeException $e) {
            die('Caught exception: ' . $e->getMessage());
        }

        $sendgrid = new SendGrid(self::API_KEY);
        try {
            $response = $sendgrid->send($email);
            echo "<pre>";
            echo $response->statusCode() . "\n";
            print_r($response->headers());
            echo $response->body() . "\n";
            echo "</pre>";
        } catch (Exception $e) {
            die('Caught exception: ' . $e->getMessage());
        }
    }
}