diff --git a/CRM/ConstituentsOnly/BAO/APIWrapper.php b/CRM/ConstituentsOnly/BAO/APIWrapper.php
new file mode 100644
index 0000000..7819b4f
--- /dev/null
+++ b/CRM/ConstituentsOnly/BAO/APIWrapper.php
@@ -0,0 +1,23 @@
+<?php
+
+class CRM_ConstituentsOnly_BAO_APIWrapper implements API_Wrapper {
+  /**
+   * the wrapper contains a method that allows you to alter the parameters of the api request (including the action and the entity)
+   */
+  public function fromApiInput($apiRequest) {
+    $params = &$apiRequest['params'];
+
+    if (!array_key_exists('do_not_trade', $params['params'])) {
+      $params['params']['do_not_trade'] = '0 AND (contact_a.do_not_trade IS NULL OR contact_a.do_not_trade = 0)';
+    }
+    return $apiRequest;
+  }
+
+  /**
+   * alter the result before returning it to the caller.
+   */
+  public function toApiOutput($apiRequest, $result) {
+    return $result;
+  }
+
+}
diff --git a/constituentsonly.php b/constituentsonly.php
index cf3d251..6749d8b 100644
--- a/constituentsonly.php
+++ b/constituentsonly.php
@@ -134,6 +134,17 @@ function constituentsonly_civicrm_queryObjects(&$queryObjects, $type) {
   }
 }
 
+/**
+ * Implements hook_civicrm_apiWrappers().
+ *
+ * @link http://wiki.civicrm.org/confluence/display/CRMDOC/hook_civicrm_apiWrappers
+ */
+function constituentsonly_civicrm_apiWrappers(&$wrappers, $apiRequest) {
+  if ($apiRequest['entity'] == 'Contact' && strtolower($apiRequest['action']) == 'getlist') {
+    $wrappers[] = new CRM_ConstituentsOnly_BAO_APIWrapper();
+  }
+}
+
 /**
  * Implements hook_civicrm_contactListQuery().
  *