curl -X GET https://api.mycentralino.com/v1/extensions/101 \
  -H "X-API-KEY: sk_mycentralino_your_api_key"

<?php
$extension = '101';
$ch = curl_init("https://api.mycentralino.com/v1/extensions/{$extension}");
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'X-API-KEY: sk_mycentralino_your_api_key'
    ]
]);

$response = curl_exec($ch);
curl_close($ch);

$data = json_decode($response, true);
print_r($data);

import requests

headers = {'X-API-KEY': 'sk_mycentralino_your_api_key'}
extension = '201'

response = requests.get(
    f'https://api.mycentralino.com/v1/extensions/{extension}',
    headers=headers
)
print(response.json())