curl https://api2.ecomailapp.cz/lists/1/segments \
  -H "key: YOUR_API_KEY" \
  -H "Content-Type: application/json"

$listId = 1;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://api2.ecomailapp.cz/lists/{$listId}/segments");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'key: YOUR_API_KEY',
    'Content-Type: application/json',
]);
$response = curl_exec($ch);
curl_close($ch);

{
  "segments": {
    "5c36008811e45": { "name": "Segment 1", "id": "5c36008811e45", "count": 860 },
    "5cbf2405a77ce": { "name": "Segment 2", "id": "5cbf2405a77ce", "count": 540 }
  }
}

{
  "message": "Not Found!"
}