diff --git a/README.md b/README.md
index 1b1d280..b40e37e 100644
--- a/README.md
+++ b/README.md
@@ -48,7 +48,7 @@ repository.
     ));
 
     // Start the purchase
-    if (!isset($_GET['status'])) {
+    if (!isset($_GET['trxid'])) {
         $url = "http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
         $response = $gateway->purchase(array(
             'amount' => "1.50",
diff --git a/src/Gateway.php b/src/Gateway.php
index 02c7bb1..cab8aac 100644
--- a/src/Gateway.php
+++ b/src/Gateway.php
@@ -4,15 +4,13 @@ namespace Omnipay\Inforbank;
 
 use Omnipay\Common\AbstractGateway;
 
-class Gateway extends AbstractGateway {
-    public function getName() {
+class Gateway extends AbstractGateway
+{
+    public function getName()
+    {
         return 'Inforbank';
     }
 
-    public function getDefaultParameters() {
-        return array();
-    }
-
     /**
      * Start a purchase request.
      * @param array $parameters An array of options
diff --git a/src/Message/AbstractRequest.php b/src/Message/AbstractRequest.php
new file mode 100644
index 0000000..ebb0b65
--- /dev/null
+++ b/src/Message/AbstractRequest.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+use Omnipay\Common\Message\AbstractRequest as BaseAbstractRequest;
+
+abstract class AbstractRequest extends BaseAbstractRequest
+{
+    abstract protected function generateSignature();
+
+    public function getClientId()
+    {
+        return $this->getParameter('clientId');
+    }
+
+    public function getClientSecret()
+    {
+        return $this->getParameter('clientSecret');
+    }
+}
diff --git a/src/Message/AbstractResponse.php b/src/Message/AbstractResponse.php
new file mode 100644
index 0000000..307f88e
--- /dev/null
+++ b/src/Message/AbstractResponse.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+use Omnipay\Common\Message\AbstractResponse as BaseAbstractResponse;
+use Omnipay\Common\Message\RequestInterface;
+
+abstract class AbstractResponse extends BaseAbstractResponse
+{
+    protected $error;
+
+    public function __construct(RequestInterface $request, $data)
+    {
+        parent::__construct($request, $data);
+        if (!$this->data->success) {
+            $this->error = (string) $this->data->error;
+        }
+    }
+}
diff --git a/src/Message/CompletePurchaseRequest.php b/src/Message/CompletePurchaseRequest.php
new file mode 100644
index 0000000..a36c223
--- /dev/null
+++ b/src/Message/CompletePurchaseRequest.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+class CompletePurchaseRequest extends AbstractRequest
+{
+    protected $endpoint = "https://inforbank.nl/api/statusRequest";
+
+    protected function generateSignature()
+    {
+        return sha1(
+            $this->getTransactionReference() . $this->getClientId() . $this->getClientSecret()
+        );
+    }
+
+    public function getTransactionReference()
+    {
+        return $this->httpRequest->query->get('trxid');
+    }
+
+    public function getData()
+    {
+        $this->validate('merchantId', 'merchantKey');
+
+        $data = array(
+            "clientId" => $this->getClientId(),
+            "clientSecret" => $this->getClientSecret(),
+            "transactionId" => $this->getTransactionReference(),
+            "sha1" => $this->generateSignature()
+        );
+    }
+
+    public function sendData($data)
+    {
+        $httpResponse = $this->httpClient->post($this->endpoint, null, $data)->send();
+        return $this->response = new CompletePurchaseResponse($this, $httpResponse->json());
+    }
+}
diff --git a/src/Message/CompletePurchaseResponse.php b/src/Message/CompletePurchaseResponse.php
new file mode 100644
index 0000000..309f2f9
--- /dev/null
+++ b/src/Message/CompletePurchaseResponse.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+class CompletePurchaseResponse extends PurchaseResponse
+{
+    public function isSuccessful()
+    {
+        return ($this->data->transaction->status === "Success");
+    }
+
+    public function isRedirect()
+    {
+        return false;
+    }
+
+    public function getStatus()
+    {
+        return $this->data->transaction->status;
+    }
+}
diff --git a/src/Message/PurchaseRequest.php b/src/Message/PurchaseRequest.php
new file mode 100644
index 0000000..7c07228
--- /dev/null
+++ b/src/Message/PurchaseRequest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+class PurchaseRequest extends AbstractRequest
+{
+    protected $endpoint = "https://inforbank.nl/api/transactionRequest";
+
+    protected function generateSignature()
+    {
+        return sha1(
+            $this->getTransactionId() . $this->getAmountInteger() . $this->getClientId() . $this->getClientSecret()
+        );
+    }
+
+    public function getData()
+    {
+        $this->validate(
+            'amount',
+            'transactionId',
+            'returnUrl'
+        );
+
+        $data = array(
+            "clientId" => $this->getClientId(),
+            "clientSecret" => $this->getClientSecret(),
+            "transactionId" => $this->getTransactionId(),
+            "amount" => $this->getAmountInteger(),
+            "description" => $this->getDescription(),
+            "returnUrl" => $this->getReturnUrl(),
+            "sha1" => $this->generateSignature()
+        );
+    }
+
+    public function sendData($data)
+    {
+        $httpResponse = $this->httpClient->post($this->endpoint, null, $data)->send();
+        return $this->response = new PurchaseResponse($this, $httpResponse->json());
+    }
+}
diff --git a/src/Message/PurchaseResponse.php b/src/Message/PurchaseResponse.php
new file mode 100644
index 0000000..b2e72e0
--- /dev/null
+++ b/src/Message/PurchaseResponse.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Omnipay\Inforbank\Message;
+
+use Omnipay\Common\Message\RedirectResponseInterface;
+
+class PurchaseResponse extends AbstractResponse implements RedirectResponseInterface
+{
+    public function isSuccessful()
+    {
+        return false;
+    }
+
+    public function isRedirect()
+    {
+        return is_null($this->error);
+    }
+
+    public function isPending()
+    {
+        return true;
+    }
+
+    public function getRedirectUrl()
+    {
+        return $this->data->redirect;
+    }
+
+    public function getRedirectMethod()
+    {
+        return 'GET';
+    }
+
+    public function getRedirectData()
+    {
+        return null;
+    }
+}