curl https://api2.ecomailapp.cz/subscribers/foo@bar.cz \
  -H "key: YOUR_API_KEY" \
  -H "Content-Type: application/json"

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

{
  "subscriber": {
    "name": "Foo",
    "surname": "Bar",
    "email": "foo@bar.cz",
    "gender": "male",
    "bounce_soft": 0,
    "bounced_hard": 0,
    "inserted_at": "2018-11-15 13:59:21",
    "rating": 2.5,
    "country": "CZ",
    "tags": ["Completed", "SomeTag"],
    "lists": {
      "1": {
        "id": 407704,
        "list_id": 1,
        "email": "foo@bar.cz",
        "status": 1,
        "subscribed_at": "2018-11-15T12:59:21.000000Z",
        "source": "app"
      }
    }
  }
}