diff --git a/commerce_paypal.module b/commerce_paypal.module
index 8767833..30efea0 100644
--- a/commerce_paypal.module
+++ b/commerce_paypal.module
@@ -471,6 +471,7 @@ function commerce_paypal_currencies($method_id) {
     case 'paypal_ppa':
       return drupal_map_assoc(array('AUD', 'CAD', 'EUR', 'GBP', 'JPY', 'USD'));
     case 'paypal_wps':
+    case 'paypal_apc':
       return drupal_map_assoc(array('AUD', 'BRL', 'CAD', 'CHF', 'CZK', 'DKK', 'EUR', 'GBP', 'HKD', 'HUF', 'ILS', 'JPY', 'MXN', 'MYR', 'NOK', 'NZD', 'PHP', 'PLN', 'SEK', 'SGD', 'THB', 'TRY', 'TWD', 'USD'));
   }
 }
diff --git a/modules/adaptive/README.md b/modules/adaptive/README.md
new file mode 100644
index 0000000..7ee1d2d
--- /dev/null
+++ b/modules/adaptive/README.md
@@ -0,0 +1,27 @@
+PayPal Adaptive Payments
+========================
+
+This module implements the [PayPal Adaptive Payments API][api] which allows for
+marketplace-style split transactions of up to 9 receivers. Transactions can be
+split or parallel and have different options for distributing fees and handling
+payments.
+
+On its own, this module will effectively act like a standard PayPal module and
+will not specify or create multiple transactions per order. In order to add
+extra receivers to an order is to use the alter hook defined in the API. You
+can find more information about that in the `commerce_paypal_adaptive.api.php`
+file in this directory.
+
+
+Setting Up
+----------
+
+You will need to [create Signature API credentials][credentials] in order to 
+use this module. Enter these API credentials into the payment configuration
+form and save it. You will also need to at least one PayPal address that can
+receive payments.
+
+
+
+ [api]: https://developer.paypal.com/docs/classic/products/adaptive-payments/
+ [credentials]: https://developer.paypal.com/docs/classic/api/apiCredentials/#creating-an-api-signature
diff --git a/modules/adaptive/commerce_paypal_adaptive.api.php b/modules/adaptive/commerce_paypal_adaptive.api.php
new file mode 100644
index 0000000..0a2af76
--- /dev/null
+++ b/modules/adaptive/commerce_paypal_adaptive.api.php
@@ -0,0 +1,62 @@
+<?php
+
+/**
+ * @file
+ * API documentation for Commerce PayPal Adaptive Payments.
+ */
+
+/**
+ * Allows a user to modify the PayPal Adaptive Payments order data.
+ *
+ * During the creation of an order, Adaptive Payments must first have an order
+ * created using a PayRequest API call. This call sets up the order that will
+ * then be executed by the sender on the following redirect.
+ *
+ * This form alter can be used by marketplace providers to add additional
+ * payment receivers or to otherwise modify the PayRequest before it gets
+ * processed by PayPal.
+ *
+ * @param array $data
+ *   The order array data structure. This data structure will be encoded as JSON
+ *   and then sent to the API. For more information, see the link below for
+ *   a full description of the PayRequest API Call.
+ *   - currencyCode: The PayPal currency code.
+ *   - actionType: The action being performed. Usually 'Pay'.
+ *   - ipnNotificationUrl: The URL that will be contacted when the order is
+ *     processed.
+ *   - cancelUrl: The URL that the customer will be sent to if they cancel the
+ *     transaction.
+ *   - returnUrl: The URL the customer will be forwarded to when they complete
+ *     the transaction.
+ *   - receiverList: Contains a single key:
+ *     - receiver: An array of arrays, 0-indexed. There can be up to 9 total
+ *       receivers listed for a single transaction. Each array will contain the
+ *       following keys:
+ *       - email: The email address of the recipient. Must be a PayPal member.
+ *       - amount: The amount that the recipient will receive. If using Chained
+ *         payments, the primary recipient's amount will be the total amount
+ *         charged to the customer and the secondary receivers will receive the
+ *         amount listed here. The primary receiver will ultimately receive the
+ *         "leftover" amount after all of the secondary receivers get their
+ *         amounts.
+ *       - primary: Optional. Defaults to false. This is automatically set by
+ *         the payment gateway. There can be only one per order. If there is no
+ *         primary receiver on an order, then it will process as a parallel and
+ *         not a chained payment.
+ *   - invoice: The unique ID given to this order for the IPN.
+ *   - requestEnvelope: A field required by the API. Please don't touch.
+ *   - memo: The memo field that will be shown on the PayPal transaction.
+ *   - feesPayer: Denotes who will pay the fees. See the API docs for further
+ *     details.
+ * @param object $order
+ *   The commerce order being considered.
+ *
+ * @see https://developer.paypal.com/docs/classic/api/adaptive-payments/Pay_API_Operation/
+ */
+function hook_commerce_paypal_apc_order_form_data_alter(&$data, $order) {
+  // Add another recipient.
+  $data['receiverList']['receiver'][] = array(
+    'email' => 'merchant@example.com',
+    'amount' => '5',
+  );
+}
diff --git a/modules/adaptive/commerce_paypal_adaptive.info b/modules/adaptive/commerce_paypal_adaptive.info
new file mode 100644
index 0000000..a61b28d
--- /dev/null
+++ b/modules/adaptive/commerce_paypal_adaptive.info
@@ -0,0 +1,9 @@
+name = PayPal Adaptive Payments
+description = Implements PayPal Adaptive Payments for use with Commerce Marketplace.
+package = Commerce (PayPal)
+dependencies[] = commerce
+dependencies[] = commerce_ui
+dependencies[] = commerce_payment
+dependencies[] = commerce_order
+dependencies[] = commerce_paypal
+core = 7.x
diff --git a/modules/adaptive/commerce_paypal_adaptive.install b/modules/adaptive/commerce_paypal_adaptive.install
new file mode 100644
index 0000000..23917bf
--- /dev/null
+++ b/modules/adaptive/commerce_paypal_adaptive.install
@@ -0,0 +1,6 @@
+<?php
+
+/**
+ * @file
+ * PayPal Adaptive Payments installation file.
+ */
diff --git a/modules/adaptive/commerce_paypal_adaptive.module b/modules/adaptive/commerce_paypal_adaptive.module
new file mode 100644
index 0000000..8e60b20
--- /dev/null
+++ b/modules/adaptive/commerce_paypal_adaptive.module
@@ -0,0 +1,471 @@
+<?php
+
+/**
+ * @file
+ * Module implementation file.
+ */
+
+/**
+ * Implements hook_commerce_payment_method_info().
+ */
+function commerce_paypal_adaptive_commerce_payment_method_info() {
+  $payment_methods = array();
+
+  $payment_methods['paypal_apc'] = array(
+    'base' => 'commerce_paypal_adaptive_chained',
+    'title' => t('PayPal Adaptive (Chained)'),
+    'short_title' => t('PayPal'),
+    'description' => t('PayPal Adaptive Payments (Chained)'),
+    'terminal' => FALSE,
+    'offsite' => TRUE,
+    'offsite_autoredirect' => TRUE,
+
+    // Because the order form generation code does not have access to a payment
+    // method info array, we set the bn directly there instead of making use of
+    // this buttonsource variable. It's here for consistency with other payment
+    // methods in this package.
+    'buttonsource' => 'CommerceGuys_Cart_APC',
+  );
+
+  return $payment_methods;
+}
+
+/**
+ * Returns the default settings for the PayPal WPS payment method.
+ */
+function commerce_paypal_adaptive_default_settings() {
+  $default_currency = commerce_default_currency();
+
+  return array(
+    'api_username' => '',
+    'api_password' => '',
+    'api_signature' => '',
+    'currency_code' => in_array($default_currency, array_keys(commerce_paypal_currencies('paypal_wps'))) ? $default_currency : 'USD',
+    'allow_supported_currencies' => FALSE,
+    'language' => 'US',
+    'server' => 'sandbox',
+    'action_type' => 'PAY',
+    'fees_payer' => 'SECONDARYONLY',
+    'ipn_logging' => 'notification',
+    'primary_receiver' => '',
+    'ipn_create_billing_profile' => FALSE,
+    'show_payment_instructions' => FALSE,
+  );
+}
+
+/**
+ * Payment method callback: settings form.
+ */
+function commerce_paypal_adaptive_chained_settings_form($settings = array()) {
+  $form = array();
+
+  // Merge default settings into the stored settings array.
+  $settings = (array) $settings + commerce_paypal_adaptive_default_settings();
+
+  $form['api_username'] = array(
+    '#type' => 'textfield',
+    '#title' => t('API username'),
+    '#default_value' => $settings['api_username'],
+  );
+  $form['api_password'] = array(
+    '#type' => 'textfield',
+    '#title' => t('API password'),
+    '#default_value' => $settings['api_password'],
+  );
+  $form['api_signature'] = array(
+    '#type' => 'textfield',
+    '#title' => t('Signature'),
+    '#default_value' => $settings['api_signature'],
+  );
+  $form['currency_code'] = array(
+    '#type' => 'select',
+    '#title' => t('Default currency'),
+    '#description' => t('Transactions in other currencies will be converted to this currency, so multi-currency sites must be configured to use appropriate conversion rates.'),
+    '#options' => commerce_paypal_currencies('paypal_apc'),
+    '#default_value' => $settings['currency_code'],
+  );
+  $form['allow_supported_currencies'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Allow transactions to use any currency in the options list above.'),
+    '#description' => t('Transactions in unsupported currencies will still be converted into the default currency.'),
+    '#default_value' => $settings['allow_supported_currencies'],
+  );
+  $form['server'] = array(
+    '#type' => 'radios',
+    '#title' => t('PayPal server'),
+    '#options' => array(
+      'sandbox' => ('Sandbox - use for testing, requires a PayPal Sandbox account'),
+      'live' => ('Live - use for processing real transactions'),
+    ),
+    '#default_value' => $settings['server'],
+  );
+  $form['action_type'] = array(
+    '#type' => 'radios',
+    '#title' => t('Payment action'),
+    '#options' => array(
+      'PAY' => t('Pay - capture and pay all receivers of a multi-receiver payment'),
+      'PAY_PRIMARY' => t('Pay Primary - pays the primary receiver of a chained payment'),
+    ),
+    '#default_value' => $settings['action_type'],
+  );
+  $form['fees_payer'] = array(
+    '#type' => 'radios',
+    '#title' => t('Who pays the fees?'),
+    '#options' => array(
+      'SENDER' => t('Sender pays the fees.'),
+      'PRIMARYRECEIVER' => t('Primary receiver pays all fees.'),
+      'EACHRECEIVER' => t('Each receiver pays their own fee.'),
+      'SECONDARYONLY' => t('Secondary receivers pay all fees.'),
+    ),
+    '#default_value' => $settings['fees_payer'],
+  );
+  $form['ipn_logging'] = array(
+    '#type' => 'radios',
+    '#title' => t('IPN logging'),
+    '#options' => array(
+      'notification' => t('Log notifications during IPN validation and processing.'),
+      'full_ipn' => t('Log notifications with the full IPN during validation and processing (used for debugging).'),
+    ),
+    '#default_value' => $settings['ipn_logging'],
+  );
+  $form['primary_receiver'] = array(
+    '#type' => 'textfield',
+    '#title' => t('PayPal primary receiver e-mail addresses'),
+    '#description' => t('Enter the primary e-mail address for your PayPal account if different from the one entered above or a comma separated list of all valid e-mail addresses on the account.') . '<br />' . t('IPNs that originate from payments made to a PayPal account whose e-mail address is not in this list will not be processed.'),
+    '#default_value' => $settings['primary_receiver'],
+  );
+  $form['ipn_create_billing_profile'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Create a billing profile based on name and country data in the IPN for any order that does not have one yet.'),
+    '#description' => t('This is most useful for sites that do not collect billing information locally but still want to have customer names on orders.'),
+    '#default_value' => $settings['ipn_create_billing_profile'],
+  );
+  $form['show_payment_instructions'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Show a message on the checkout form when PayPal Adaptive Payments is selected telling the customer to "Continue with checkout to complete payment via PayPal."'),
+    '#default_value' => $settings['show_payment_instructions'],
+  );
+
+  return $form;
+}
+
+/**
+ * Payment method callback.
+ *
+ * Adds a message to the submission form if enabled in the payment method
+ * settings.
+ */
+function commerce_paypal_adaptive_chained_submit_form($payment_method, $pane_values, $checkout_pane, $order) {
+  $form = array();
+
+  if (!empty($payment_method['settings']['show_payment_instructions'])) {
+    $form['paypal_apc_information'] = array(
+      '#markup' => '<span class="commerce-paypal-apc-info">' . t('(Continue with checkout to complete payment via PayPal.)') . '</span>',
+    );
+  }
+
+  return $form;
+}
+
+/**
+ * Implements hook_form_FORM_ID_alter().
+ */
+function commerce_paypal_adaptive_form_commerce_checkout_form_alter(&$form, &$form_state) {
+  // If this checkout form contains the payment method radios...
+  if (!empty($form['commerce_payment']['payment_method']['#options'])) {
+    // Loop over its options array looking for a PayPal WPS option.
+    foreach ($form['commerce_payment']['payment_method']['#options'] as $key => &$value) {
+      list($method_id, $rule_name) = explode('|', $key);
+
+      // If we find PayPal WPS...
+      if ($method_id == 'paypal_apc') {
+        // Prepare the replacement radio button text with icons.
+        $icons = commerce_paypal_icons();
+        $value = t('!logo PayPal - pay securely without sharing your financial information', array('!logo' => $icons['paypal']));
+        $value .= '<div class="commerce-paypal-icons"><span class="label">' . t('Includes:') . '</span>' . implode(' ', $icons) . '</div>';
+
+        // Add the CSS.
+        $form['commerce_payment']['payment_method']['#attached']['css'][] = drupal_get_path('module', 'commerce_paypal_adaptive') . '/theme/commerce_paypal_adaptive.theme.css';
+
+        break;
+      }
+    }
+  }
+}
+
+/**
+ * Payment method callback: redirect form.
+ */
+function commerce_paypal_adaptive_chained_redirect_form($form, &$form_state, $order, $payment_method) {
+  // Return an error if the enabling action's settings haven't been configured.
+  if (empty($payment_method['settings']['primary_receiver'])) {
+    drupal_set_message(t('PayPal Adaptive is not configured for use. No PayPal e-mail address has been specified.'), 'error');
+    return array();
+  }
+
+  $settings = array(
+    // Return to the previous page when payment is canceled.
+    'cancel_return' => url('checkout/' . $order->order_id . '/payment/back/' . $order->data['payment_redirect_key'], array('absolute' => TRUE)),
+    // Return to the payment redirect page for processing successful payments.
+    'return' => url('checkout/' . $order->order_id . '/payment/return/' . $order->data['payment_redirect_key'], array('absolute' => TRUE)),
+    // Specify the current payment method instance ID in the notify_url.
+    'payment_method' => $payment_method['instance_id'],
+  );
+
+  return commerce_paypal_adaptive_chained_order_form($form, $form_state, $order, $payment_method['settings'] + $settings);
+}
+
+/**
+ * Payment method callback: redirect form return validation.
+ */
+function commerce_paypal_adaptive_chained_redirect_form_validate($order, $payment_method) {
+  if (!empty($payment_method['settings']['ipn_logging']) &&
+    $payment_method['settings']['ipn_logging'] == 'full_ipn') {
+    watchdog('commerce_paypal_wps', 'Customer returned from PayPal with the following POST data: !ipn_data', array('!ipn_data' => '<pre>' . check_plain(print_r($_POST, TRUE)) . '</pre>'), WATCHDOG_NOTICE);
+  }
+
+  // This may be an unnecessary step, but if for some reason the user does end
+  // up returning at the success URL with a Failed payment, go back.
+  if (!empty($_POST['payment_status']) && $_POST['payment_status'] == 'Failed') {
+    return FALSE;
+  }
+}
+
+/**
+ * Payment method callback: redirect form return submission.
+ */
+function commerce_paypal_adaptive_chained_redirect_form_submit($order, $payment_method) {
+  // Nothing here yet.
+}
+
+/**
+ * Implements hook_commerce_paypal_ipn_process().
+ */
+function commerce_paypal_adaptive_commerce_paypal_ipn_process($order, $payment_method, $ipn) {
+  // @todo Implement.
+}
+
+/**
+ * Builds a Website Payments Standard form from an order object.
+ *
+ * @param object $order
+ *   The fully loaded order being paid for.
+ * @param array $settings
+ *   An array of settings used to build out the form, including:
+ *   - server: which server to use, either sandbox or live
+ *   - business: the PayPal e-mail address the payment submits to
+ *   - cancel_return: the URL PayPal should send the user to on cancellation
+ *   - return: the URL PayPal should send the user to on successful payment
+ *   - currency_code: the PayPal currency code to use for this payment if the
+ *     total for the order is in a non-PayPal supported currency
+ *   - language: the PayPal language code to use on the payment form
+ *   - action_type: the PayPal payment action to use: sale, authorization,
+ *     or order
+ *   - payment_method: optionally a payment method instance ID to include in the
+ *     IPN notify_url.
+ *
+ * @return array
+ *   A renderable form array.
+ */
+function commerce_paypal_adaptive_chained_order_form($form, &$form_state, $order, $settings) {
+  $wrapper = entity_metadata_wrapper('commerce_order', $order);
+
+  // Determine the currency code to use to actually process the transaction,
+  // which will either be the default currency code or the currency code of the
+  // order if it's supported by PayPal if that option is enabled.
+  $currency_code = $settings['currency_code'];
+  $order_currency_code = $wrapper->commerce_order_total->currency_code->value();
+
+  if (!empty($settings['allow_supported_currencies']) && in_array($order_currency_code, array_keys(commerce_paypal_currencies('paypal_wps')))) {
+    $currency_code = $order_currency_code;
+  }
+
+  $amount = $wrapper->commerce_order_total->amount->value();
+
+  // Ensure a default value for the payment_method setting.
+  $settings += array('payment_method' => '');
+
+  // Build the data array that will be translated into hidden form values.
+  $data = array(
+    // Specify the checkout experience to present to the user.
+    'actionType' => $settings['action_type'],
+    // The path PayPal should send the IPN to.
+    'ipnNotificationUrl' => commerce_paypal_ipn_url($settings['payment_method']),
+    // Return to the review page when payment is canceled.
+    'cancelUrl' => $settings['cancel_return'],
+    // Return to the payment redirect page for processing successful payments.
+    'returnUrl' => $settings['return'],
+    // Set the currency and language codes.
+    'currencyCode' => $currency_code,
+
+    // Primary Receiver information.
+    'receiverList' => array(
+      'receiver' => array(
+        array(
+          'email' => $settings['primary_receiver'],
+          'amount' => commerce_paypal_price_amount(commerce_currency_convert($amount, $order_currency_code, $currency_code), $currency_code),
+          'primary' => 'true',
+        ),
+      ),
+    ),
+
+    // Use the timestamp to generate a unique invoice number.
+    'invoice' => commerce_paypal_ipn_invoice($order),
+    // Required.
+    'requestEnvelope' => array(
+      'errorLanguage' => 'en_US',
+    ),
+    // Shown on the checkout page.
+    'memo' => t('Order #@order', array('@order' => $order->order_id)),
+    // Who is paying the fees?
+    'feesPayer' => $settings['fees_payer'],
+  );
+
+  // Allow modules to alter parameters of the API request.
+  drupal_alter('commerce_paypal_apc_order_form_data', $data, $order, $settings);
+
+  $response = commerce_paypal_adaptive_payrequest($data, $settings);
+
+  if ($response !== FALSE) {
+    if ($response['responseEnvelope']['ack'] == 'Success') {
+      $form['#action'] = commerce_paypal_adaptive_redirect_url($response['payKey'], $settings);
+      $form['submit'] = array(
+        '#type' => 'submit',
+        '#value' => t('Proceed to PayPal'),
+      );
+    }
+    else {
+      watchdog('commerce_paypal_adaptive', 'Error #!error_id creating transaction: !message<br />!error_object', array(
+        '!error_id' => $response['error'][0]['errorId'],
+        '!message' => $response['error'][0]['message'],
+        '!error_object' => '<pre>' . print_r($response['error'][0], TRUE) . '</pre>',
+      ), WATCHDOG_ERROR);
+      drupal_set_message(t('Unable to initialize transaction with PayPal.'), 'error');
+      drupal_goto($settings['cancel_return']);
+    }
+  }
+  else {
+    drupal_set_message(t('Unable to initialize transaction with PayPal.'), 'error');
+    drupal_goto($settings['cancel_return']);
+  }
+
+  return $form;
+}
+
+/**
+ * Returns the URL to the specified PayPal Adaptive server.
+ *
+ * @param string $server
+ *   Either sandbox or live indicating which server to get the URL for.
+ *
+ * @return string
+ *   The URL to use to submit requests to the PayPal Adaptive server.
+ */
+function commerce_paypal_adaptive_server_url($server) {
+  switch ($server) {
+    case 'sandbox':
+      return 'https://www.sandbox.paypal.com/cgi-bin/webscr';
+
+    case 'live':
+      return 'https://www.paypal.com/cgi-bin/webscr';
+  }
+}
+
+/**
+ * Perform a PayPal Adaptive Payments PayRequest Request.
+ *
+ * @param array $params
+ *   The parameters for the request. See the PayPal API page (linked below) for
+ *   more information. This structure will be converted to JSON and sent to the
+ *   PayPal API.
+ * @param array $settings
+ *   Payment method settings array.
+ *
+ * @return mixed
+ *   A response object or FALSE if the request could not be completed.
+ *
+ * @see https://developer.paypal.com/docs/classic/api/adaptive-payments/Pay_API_Operation/
+ */
+function commerce_paypal_adaptive_payrequest($params, $settings) {
+  if ($settings['ipn_logging'] == 'full_ipn') {
+    watchdog('commerce_paypal_adaptive', 'PayPal Adaptive PayRequest Request: !ipn_data', array('!ipn_data' => '<pre>' . check_plain(print_r($params, TRUE)) . '</pre>'));
+  }
+
+  $response = commerce_paypal_adaptive_post($params, 'Pay', $settings);
+
+  if ($settings['ipn_logging'] == 'full_ipn') {
+    watchdog('commerce_paypal_adaptive', 'PayPal Adaptive PayRequest Response: !ipn_data', array('!ipn_data' => '<pre>' . check_plain(print_r($response, TRUE)) . '</pre>'));
+  }
+
+  return $response;
+}
+
+/**
+ * Perform an API POST operation.
+ *
+ * @param array $post_data
+ *   The data to post to the API.
+ * @param string $type
+ *   The endpoint to post to. Usually 'Pay' or 'PaymentDetails'.
+ * @param array $settings
+ *   Payment method settings array.
+ *
+ * @return mixed
+ *   The decoded API response.
+ */
+function commerce_paypal_adaptive_post($post_data, $type, $settings) {
+  if ($type != 'Pay' && $type != 'PaymentDetails') {
+    drupal_set_message(t('Invalid PayPal Adaptive Payment request: @type.', array('@type' => $type)), 'error');
+    watchdog('commerce_paypal_adaptive', 'Invalid PayPal Adaptive Payment request: @type.', array('@type' => $type), WATCHDOG_ERROR);
+  }
+
+  if ($settings['server'] == 'sandbox') {
+    $url = 'https://svcs.sandbox.paypal.com/AdaptivePayments/';
+    $application_id = 'APP-80W284485P519543T';
+  }
+  else {
+    $url = 'https://svcs.paypal.com/AdaptivePayments/';
+    $application_id = $settings['application_id'];
+  }
+
+  $curl = curl_init($url . $type);
+
+  curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'POST');
+  curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
+  curl_setopt($curl, CURLOPT_POSTFIELDS, drupal_json_encode($post_data));
+  curl_setopt($curl, CURLOPT_HTTPHEADER, array(
+    'X-PAYPAL-SECURITY-USERID: ' . $settings['api_username'],
+    'X-PAYPAL-SECURITY-PASSWORD: ' . $settings['api_password'],
+    'X-PAYPAL-SECURITY-SIGNATURE: ' . $settings['api_signature'],
+    'X-PAYPAL-REQUEST-DATA-FORMAT: JSON',
+    'X-PAYPAL-RESPONSE-DATA-FORMAT: JSON',
+    'X-PAYPAL-APPLICATION-ID: ' . $application_id,
+  ));
+
+  $result = curl_exec($curl);
+
+  curl_close($curl);
+
+  return drupal_json_decode($result);
+}
+
+/**
+ * Generate the redirect URL for an Adaptive Payments payKey.
+ *
+ * @param string $pay_key
+ *   The payKey returned by a successful PayRequest.
+ * @param array $settings
+ *   Payment method settings array.
+ *
+ * @return string
+ *   The URL that the customer will be redirected to in order to complete their
+ *   transaction.
+ */
+function commerce_paypal_adaptive_redirect_url($pay_key, $settings) {
+  $server_url = commerce_paypal_adaptive_server_url($settings['server']);
+  $params = array(
+    'cmd' => '_ap-payment',
+    'paykey' => $pay_key,
+  );
+  return $server_url . '?' . http_build_query($params);
+}