install the package:

composer require adresslabor/check-service

how to use the checkClient:

// initialize the checkClient
$apiCid = "0000";
$apiKey = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
$associative = true;

// The client will test your credentials first
$checkClient = new \Adresslabor\CheckService\CheckClient($apiCid, $apiKey, $associative);

// get your available credits
$availableCredits = $checkClient->credits;

// https://adresslabor.de/de/produkte/adress-check-dach.html
$scResult = $checkClient->addressCheckDACH("Kolping Str.", "14", "63768", "Hösbach", "DE");
$scxResult = $checkClient->addressCheckDACH("Kolping Str.", "14", "63768", "Hösbach", "DE", true);

// https://adresslabor.de/de/produkte/adress-check-world.html
$scIntResult = $checkClient->addressCheckWorld("Kolping Str.", "14", "63768", "Hösbach", "DE","","","", "", "", "");

// https://adresslabor.de/de/produkte/fake-check.html
$fkResult = $checkClient->fakeCheck("Donald", "Duck", "Kolping Str.", "14", "63768", "Hösbach", "DE");

// https://adresslabor.de/de/produkte/name-check-b2c.html
$ncResult = $checkClient->nameCheckB2C("Rolf", "Paschold", "Frau", "Dr.");

// https://adresslabor.de/de/produkte/e-mail-check.html
$emResult = $checkClient->emailCheck("prof@adresslabor.de");
$emxResult = $checkClient->emailCheck("prof@adresslabor.de", true);

// https://adresslabor.de/de/produkte/telefonverzeichnis.html
$pbResult = $checkClient->telephoneDirectory("Donald", "Duck", "Kolping Str.", "63768", "Hösbach", "DE", "+4912345789", "Dr.", "14");
$pbtResult = $checkClient->telephoneDirectory("Donald", "Duck", "Kolping Str.", "63768", "Hösbach", "DE", "+4912345789", "Dr.", "14", true);

// https://adresslabor.de/de/produkte/ust-idnr-check.html
$vatidResult = $checkClient->vatNumberCheck("DE304496992");
$vatidxResult = $checkClient->vatNumberCheck("DE304496992", true);

// execute multiple checks in one single request
$multiCheckResult = $checkClient->check(\Adresslabor\CheckClient::PATH_V3, [
    'product' => 'fk,nc,scx',
    'firstname' => 'Rolf',
    'lastname' => 'Paschold',
    'street' => 'Kolping Str.',
    'hno' => '14',
    'zip' => '63768',
    'city' => 'Hösbach'
]);

// Url of the service
  $url = 'https://api.adresslabor.de/v1/de/check';

  $fields = array(
    'product'      => 'EMX,SC,FK,PB,NC',
    'firstname'    => 'Max',
    'lastname'     => 'Mustermann',
    'street'       => 'Teststr.',
    'hno'          => '9',
    'zip'          => '12345',
    'city'         => 'Entenhausen',
    'country'      => 'DE',
    'phone'        => '01234/56789',
    'email'        => 'test@test-email.de',
    'apicid'       => 1,
    'apikey'       => 'ffffffff-ffff-ffff-ffff-ffffffffffff'
  );

  //Open connection.
  $ch = curl_init();

  // Set the right curl-options.
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($fields));
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

  //Execute post and close connection.
  $result = curl_exec($ch);
  curl_close($ch);

  // Decode json-data
  $result = json_decode($result);

  // Access the complete result.
  print_r($result)

  // Access the email-check-result.
  print_r($result -> em);

  // Access the email-resulttext.
  print_r($result -> em -> resulttext);