MercadoPago with PHP --> SIMPLE!

get_pref_id.php

<?php
$mp = new MP('YOUR_CLIENT_ID', 'YOUR_CLIENT_SECRET');

$preference_data = [
            "items" => [
               [
                   "title" => "Your product name ",
                   "id" => "yourProductId",
                   "external_reference" => "yourProductId", // used on webhook
                   "quantity" => 1,
                   "currency_id" => "ARS",
                   "unit_price" => 9.99
               ]
            ],"payer" => [
               "email" => $client_email // this is optional
            ]
        ];
$preference_array = $mp->create_preference($preference_data);

$pref_id = $preference['response']['id'];

receive_token_mercadopago.php

<?php
// se configura aquí: https://www.mercadopago.com/mla/herramientas/notificaciones

$ref = $arr = false;
try {
    // tell PHP to log errors to receive_token_mercadopago.log in this directory
    ini_set('log_errors', true);
    ini_set('error_log', __DIR__ . '/receive_token_mercadopago-errors.log');

    $operation_id = $_GET['id'];

    $mp = new MP('YOUR_CLIENT_ID', 'YOUR_CLIENT_SECRET');

    $arr_tmp = $mp->get_payment($operation_id);
    $arr = $arr_tmp['response']['collection'];
      
    // some fixes for MercadoPago 2017
    if (strpos($arr['external_reference'], '%') !== false) {
        $refstr = urldecode($arr['external_reference']);
    } else {
        $refstr = $arr['external_reference'];
    }

    if ($arr['status'] == 'approved')
    {
        // pago recibido del producto $arr['reason']
        // revisar el monto pagado y la moneda para evitar hacks
    }
} catch (Exception $e) {
    $ret = mail('[email protected]', 'ERROR ping mercadopago: ' . $e->getMessage(),
        $_SERVER['REQUEST_URI'] . "\n\n"
        . 'refstr: ' . ($refstr ?? '(not setted)') . "\n\n"
        . 'ref: ' . print_r($ref, true) . "\n\n"
        . 'GET: ' . print_r($_GET, true) . "\n\n"
        . 'POST: ' . print_r($_POST, true) . "\n\n"
        . 'DATA: ' . print_r($arr, true));
    if (!$ret && $e->getCode() != 500)
        $header->setHttpCode(404);

    error_log($e->getMessage());
}

exit;

Simple-MercadoPago-PHP.md

Send your users to https://www.mercadopago.com/mla/checkout/pay?pref_id=$pref_id