diff --git a/pronamic-pay-adyen.php b/pronamic-pay-adyen.php
index 7b4410e..cb084bc 100644
--- a/pronamic-pay-adyen.php
+++ b/pronamic-pay-adyen.php
@@ -37,7 +37,7 @@
  */
 add_filter(
 	'pronamic_pay_gateways',
-	function( $gateways ) {
+	function ( $gateways ) {
 		$gateways[] = new \Pronamic\WordPress\Pay\Gateways\Adyen\Integration(
 			[
 				'id'            => 'adyen',
diff --git a/src/AdditionalData.php b/src/AdditionalData.php
index 3e9c5f4..872728a 100644
--- a/src/AdditionalData.php
+++ b/src/AdditionalData.php
@@ -183,7 +183,7 @@ public function get_json() {
 
 				$properties = array_merge( $properties, $item_properties );
 
-				$index++;
+				++$index;
 			}
 		}
 
diff --git a/src/Gateway.php b/src/Gateway.php
index 0200872..d85454a 100644
--- a/src/Gateway.php
+++ b/src/Gateway.php
@@ -78,7 +78,7 @@ public function __construct( Config $config ) {
 
 		$ideal_issuer_field->set_options(
 			new CachedCallbackOptions(
-				function() {
+				function () {
 					return $this->get_ideal_issuers();
 				},
 				'pronamic_pay_ideal_issuers_' . \md5( \wp_json_encode( $config ) )
diff --git a/src/LineItems.php b/src/LineItems.php
index f884e50..f7b6e4d 100644
--- a/src/LineItems.php
+++ b/src/LineItems.php
@@ -87,7 +87,7 @@ public function get_json() {
 			 * @param LineItem $item Line item.
 			 * @return object
 			 */
-			function( LineItem $item ) {
+			function ( LineItem $item ) {
 				return $item->get_json();
 			},
 			$this->get_line_items()
diff --git a/src/NotificationsController.php b/src/NotificationsController.php
index 564ea6e..9bbf705 100644
--- a/src/NotificationsController.php
+++ b/src/NotificationsController.php
@@ -13,7 +13,7 @@
 use JsonSchema\Exception\ValidationException;
 use Pronamic\WordPress\Pay\Core\Server;
 use Pronamic\WordPress\Pay\Payments\Payment;
-use Pronamic\WordPress\Pay\Payments\PaymentStatus as PaymentStatus;
+use Pronamic\WordPress\Pay\Payments\PaymentStatus;
 use WP_Error;
 use WP_REST_Request;
 
diff --git a/src/ReturnController.php b/src/ReturnController.php
index cbccbf5..1b22950 100644
--- a/src/ReturnController.php
+++ b/src/ReturnController.php
@@ -50,7 +50,7 @@ public function rest_api_init() {
 			[
 				'methods'             => 'GET',
 				'callback'            => [ $this, 'rest_api_adyen_return' ],
-				'permission_callback' => function() {
+				'permission_callback' => function () {
 					return true;
 				},
 				'args'                => [