Botão URL

<?php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.robomensageiro.com.br/api/messages/sendURLBTN',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 0,
  CURLOPT_FOLLOWLOCATION => true,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_POSTFIELDS =>'{
    "number": "5511978097649",
    "customData": {
    "body": "Aqui vem o Body",
    "name": "cta_copy",
    "params": "{\\"display_text\\":\\"Ir para Site2\\",\\"id\\":\\"aaaaaa-2863-43eb-2b31-17a8f4132689\\",\\"url\\":\\"https://www.robomensageiro.com.br\\",\\"disabled\\":false}"
    }
  }',
  CURLOPT_HTTPHEADER => array(
    'Content-Type: application/json',
    'Authorization: Bearer seutokenaqui' //Token cadastrado na conexão
  ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;