diff --git a/assets/js/src/subscribers/importExport/import.js b/assets/js/src/subscribers/importExport/import.js
index 1a34d6331b..cf2fee7c91 100644
--- a/assets/js/src/subscribers/importExport/import.js
+++ b/assets/js/src/subscribers/importExport/import.js
@@ -191,39 +191,33 @@ define(
           mailChimpKeyVerifyButtonElement.click(function () {
             MailPoet.Modal.loading(true);
             MailPoet.Ajax.post({
-              endpoint: 'ImportExport',
+              endpoint: 'importExport',
               action: 'getMailChimpLists',
-              data: {api_key: mailChimpKeyInputElement.val()}
-            }).done(function (response) {
-              if (response.result === false) {
-                MailPoet.Notice.hide();
-                MailPoet.Notice.error(response.errors);
-                jQuery('.mailpoet_mailchimp-key-status')
-                    .removeClass()
-                    .addClass('mailpoet_mailchimp-key-status mailpoet_mailchimp-error');
+              data: {
+                api_key: mailChimpKeyInputElement.val()
+              }
+            }).always(function() {
+              MailPoet.Modal.loading(false);
+            }).done(function(response) {
+              jQuery('.mailpoet_mailchimp-key-status')
+                  .html('')
+                  .removeClass()
+                  .addClass('mailpoet_mailchimp-key-status mailpoet_mailchimp-ok');
+              if (response.data.length === 0) {
+                jQuery('.mailpoet_mailchimp-key-status').html(MailPoet.I18n.t('noMailChimpLists'));
                 mailChimpListsContainerElement.hide();
                 toggleNextStepButton(mailChimpProcessButtonElement, 'off');
               } else {
-                jQuery('.mailpoet_mailchimp-key-status')
-                    .html('')
-                    .removeClass()
-                    .addClass('mailpoet_mailchimp-key-status mailpoet_mailchimp-ok');
-                if (!response.data) {
-                  jQuery('.mailpoet_mailchimp-key-status').html(MailPoet.I18n.t('noMailChimpLists'));
-                  mailChimpListsContainerElement.hide();
-                  toggleNextStepButton(mailChimpProcessButtonElement, 'off');
-                } else {
-                  displayMailChimpLists(response.data);
-                }
+                displayMailChimpLists(response.data);
+              }
+            }).fail(function(response) {
+              if (response.errors.length > 0) {
+                MailPoet.Notice.error(
+                  response.errors.map(function(error) { return error.message; }),
+                  { scroll: true }
+                );
               }
-              MailPoet.Modal.loading(false);
-            }).fail(function (error) {
-              MailPoet.Modal.loading(false);
-              MailPoet.Notice.error(
-                  MailPoet.I18n.t('serverError') + error.statusText.toLowerCase() + '.'
-              );
             });
-            MailPoet.Modal.loading(false);
           });
 
           mailChimpProcessButtonElement.click(function () {
@@ -232,27 +226,24 @@ define(
             }
             MailPoet.Modal.loading(true);
             MailPoet.Ajax.post({
-              endpoint: 'ImportExport',
+              endpoint: 'importExport',
               action: 'getMailChimpSubscribers',
               data: {
                 api_key: mailChimpKeyInputElement.val(),
                 lists: mailChimpListsContainerElement.find('select').val()
               }
+            }).always(function(response) {
+              MailPoet.Modal.loading(false);
             }).done(function (response) {
-              if (response.result === true) {
-                importData.step1 = response.data;
-                router.navigate('step2', {trigger: true});
-              }
-              else {
-                MailPoet.Notice.hide();
-                MailPoet.Notice.error(response.errors);
-              }
-              MailPoet.Modal.loading(false);
+              importData.step1 = response.data;
+              router.navigate('step2', {trigger: true});
             }).fail(function () {
-              MailPoet.Modal.loading(false);
-              MailPoet.Notice.error(
-                  MailPoet.I18n.t('serverError') + result.statusText.toLowerCase() + '.'
-              );
+              if (response.errors.length > 0) {
+                MailPoet.Notice.error(
+                  response.errors.map(function(error) { return error.message; }),
+                  { scroll: true }
+                );
+              }
             });
           });
 
@@ -571,79 +562,54 @@ define(
                 })
           }
 
-          jQuery('.mailpoet_create_segment').click(function () {
+          jQuery('.mailpoet_create_segment').click(function() {
             MailPoet.Modal.popup({
               title: MailPoet.I18n.t('addNewList'),
               template: jQuery('#new_segment_template').html()
             })
-            jQuery('#new_segment_name').keypress(function (e) {
+            jQuery('#new_segment_name').keypress(function(e) {
               if (e.which == 13) {
                 jQuery('#new_segment_process').click();
               }
             });
             jQuery('#new_segment_process').click(function () {
-              var segmentName = jQuery('#new_segment_name').val().trim(),
-                  segmentDescription = jQuery('#new_segment_description').val().trim(),
-                  isDuplicateListName = ( jQuery.map(mailpoetSegments, function (el) {
-                    if (el.name.toLowerCase() === segmentName.toLowerCase()) {
-                      return true;
-                    }
-                  }).length && segmentName) ? true : false;
-              if (segmentName === '') {
-                jQuery('.mailpoet_validation_error[data-error="segment_name_required"]:hidden').show();
-              } else {
-                jQuery('.mailpoet_validation_error[data-error="segment_name_required"]:visible').hide();
-              }
-              if (isDuplicateListName) {
-                jQuery('.mailpoet_validation_error[data-error="segment_name_not_unique"]:hidden').show();
-              } else {
-                jQuery('.mailpoet_validation_error[data-error="segment_name_not_unique"]:visible').hide();
-              }
-              if (segmentName && !isDuplicateListName) {
-                jQuery('.mailpoet_validation_error[data-error="segment_name_required"]:visible').hide();
-                MailPoet.Ajax
-                    .post({
-                      endpoint: 'ImportExport',
-                      action: 'addSegment',
-                      data: {
-                        name: segmentName,
-                        description: segmentDescription
-                      }
-                    })
-                    .done(function (response) {
-                      if (response.result === true) {
-                        mailpoetSegments.push({
-                          'id': response.segment.id,
-                          'name': response.segment.name
-                        });
+              var segmentName = jQuery('#new_segment_name').val().trim();
+              var segmentDescription = jQuery('#new_segment_description').val().trim();
 
-                        var selected_values = segmentSelectElement.val();
-                        if (selected_values === null) {
-                          selected_values = [response.segment.id]
-                        } else {
-                          selected_values.push(response.segment.id);
-                        }
+              MailPoet.Ajax.post({
+                endpoint: 'ImportExport',
+                action: 'addSegment',
+                data: {
+                  name: segmentName,
+                  description: segmentDescription
+                }
+              }).done(function(response) {
+                mailpoetSegments.push({
+                  'id': response.data.id,
+                  'name': response.data.name
+                });
 
-                        enableSegmentSelection(mailpoetSegments);
-                        segmentSelectElement.val(selected_values).trigger('change');
-                        jQuery('.mailpoet_segments:hidden').show();
-                        jQuery('.mailpoet_no_segments:visible').hide();
-                        MailPoet.Modal.close();
-                      }
-                      else {
-                        MailPoet.Modal.close();
-                        MailPoet.Notice.error(
-                            MailPoet.I18n.t('segmentCreateError') + response.message + '.'
-                        );
-                      }
-                    })
-                    .fail(function (error) {
-                      MailPoet.Modal.close();
-                      MailPoet.Notice.error(
-                          MailPoet.I18n.t('serverError') + error.statusText.toLowerCase() + '.'
-                      );
-                    });
-              }
+                var selected_values = segmentSelectElement.val();
+                if (selected_values === null) {
+                  selected_values = [response.data.id]
+                } else {
+                  selected_values.push(response.data.id);
+                }
+
+                enableSegmentSelection(mailpoetSegments);
+                segmentSelectElement.val(selected_values).trigger('change');
+                jQuery('.mailpoet_segments:hidden').show();
+                jQuery('.mailpoet_no_segments:visible').hide();
+                MailPoet.Modal.close();
+              }).fail(function(response) {
+                if (response.errors.length > 0) {
+                  MailPoet.Notice.hide();
+                  MailPoet.Notice.error(
+                    response.errors.map(function(error) { return error.message; }),
+                    { positionAfter: '#new_segment_name' }
+                  );
+                }
+              });
             });
             jQuery('#new_segment_cancel').click(function () {
               MailPoet.Modal.close();
@@ -769,51 +735,49 @@ define(
                       action: 'save',
                       data: data
                     }).done(function(response) {
-                      if(response.result === true) {
-                        var new_column_data = {
-                          'id': response.field.id,
-                          'name': response.field.name,
-                          'type': response.field.type,
-                          'params': response.field.params,
-                          'custom': true
-                        };
-                        // if this is the first custom column, create an "optgroup"
-                        if (mailpoetColumnsSelect2.length === 2) {
-                          mailpoetColumnsSelect2.push({
-                            'name': MailPoet.I18n.t('userColumns'),
-                            'children': []
-                          });
-                        }
-                        mailpoetColumnsSelect2[2].children.push(new_column_data);
-                        mailpoetColumns.push(new_column_data);
-                        jQuery('select.mailpoet_subscribers_column_data_match')
-                          .each(function () {
-                            jQuery(this)
-                              .html('')
-                              .select2('destroy')
-                              .select2({
-                                data: mailpoetColumnsSelect2,
-                                width: '15em',
-                                templateResult: function (item) {
-                                  return item.name;
-                                },
-                                templateSelection: function (item) {
-                                  return item.name;
-                                }
-                              })
-                          });
-                        jQuery(selectElement).data('column-id', new_column_data.id);
-                        jQuery(selectElement).data('validation-rule', false);
-                        filterSubscribers();
-                        // close popup
-                        MailPoet.Modal.close();
+                      var new_column_data = {
+                        'id': response.data.id,
+                        'name': response.data.name,
+                        'type': response.data.type,
+                        'params': response.data.params,
+                        'custom': true
+                      };
+                      // if this is the first custom column, create an "optgroup"
+                      if (mailpoetColumnsSelect2.length === 2) {
+                        mailpoetColumnsSelect2.push({
+                          'name': MailPoet.I18n.t('userColumns'),
+                          'children': []
+                        });
                       }
-                      else {
-                        if(response.errors.length > 0) {
-                          jQuery(response.errors).each(function(i, error) {
-                            MailPoet.Notice.error(error, {positionAfter: '#field_name'});
-                          });
-                        }
+                      mailpoetColumnsSelect2[2].children.push(new_column_data);
+                      mailpoetColumns.push(new_column_data);
+                      jQuery('select.mailpoet_subscribers_column_data_match')
+                        .each(function () {
+                          jQuery(this)
+                            .html('')
+                            .select2('destroy')
+                            .select2({
+                              data: mailpoetColumnsSelect2,
+                              width: '15em',
+                              templateResult: function (item) {
+                                return item.name;
+                              },
+                              templateSelection: function (item) {
+                                return item.name;
+                              }
+                            })
+                        });
+                      jQuery(selectElement).data('column-id', new_column_data.id);
+                      jQuery(selectElement).data('validation-rule', false);
+                      filterSubscribers();
+                      // close popup
+                      MailPoet.Modal.close();
+                    }).fail(function(response) {
+                      if (response.errors.length > 0) {
+                        MailPoet.Notice.error(
+                          response.errors.map(function(error) { return error.message; }),
+                          { positionAfter: '#field_name' }
+                        );
                       }
                     });
                     return false;
@@ -975,11 +939,11 @@ define(
             nextStepButton.addClass(disabled);
           }
 
-          previousStepButton.off().click(function () {
-            router.navigate('step1', {trigger: true});
+          previousStepButton.off().on('click', function () {
+            router.navigate('step1', { trigger: true });
           });
 
-          nextStepButton.off().click(function () {
+          nextStepButton.off().on('click', function () {
             if (jQuery(this).hasClass('button-disabled')) {
               return;
             }
@@ -1019,37 +983,33 @@ define(
               });
 
             _.each(subscribers, function () {
-              queue.add(function (queue) {
+              queue.add(function(queue) {
                 queue.pause();
-                MailPoet.Ajax
-                  .post({
-                    endpoint: 'ImportExport',
-                    action: 'processImport',
-                    data: JSON.stringify({
-                      columns: columns,
-                      subscribers: subscribers[batchNumber],
-                      timestamp: timestamp,
-                      segments: segmentSelectElement.val(),
-                      updateSubscribers: (jQuery(':radio[name="subscriber_update_option"]:checked').val() === 'yes') ? true : false
-                    })
+                MailPoet.Ajax.post({
+                  endpoint: 'ImportExport',
+                  action: 'processImport',
+                  data: JSON.stringify({
+                    columns: columns,
+                    subscribers: subscribers[batchNumber],
+                    timestamp: timestamp,
+                    segments: segmentSelectElement.val(),
+                    updateSubscribers: (jQuery(':radio[name="subscriber_update_option"]:checked').val() === 'yes') ? true : false
                   })
-                  .done(function (response) {
-                    if (response.result === false) {
-                      importResults.errors.push(response.errors);
-                    } else {
-                      importResults.created = response.data.created;
-                      importResults.updated = response.data.updated;
-                      importResults.segments = response.data.segments;
-                      importResults.added_to_segment_with_welcome_notification = response.data.added_to_segment_with_welcome_notification;
-                    }
-                    queue.run();
-                  })
-                  .fail(function (error) {
-                    importResults.errors.push(
-                      MailPoet.I18n.t('serverError') + error.statusText.toLowerCase() + '.'
+                }).done(function(response) {
+                  importResults.created = response.data.created;
+                  importResults.updated = response.data.updated;
+                  importResults.segments = response.data.segments;
+                  importResults.added_to_segment_with_welcome_notification = response.data.added_to_segment_with_welcome_notification;
+                  queue.run();
+                }).fail(function(response) {
+                  MailPoet.Modal.loading(false);
+                  if (response.errors.length > 0) {
+                    MailPoet.Notice.error(
+                      response.errors.map(function(error) { return error.message; }),
+                      { scroll: true }
                     );
-                    queue.run();
-                  });
+                  }
+                });
                 batchNumber++;
               })
             });
diff --git a/lib/API/Endpoints/ImportExport.php b/lib/API/Endpoints/ImportExport.php
index a538ae65d5..07be60eb49 100644
--- a/lib/API/Endpoints/ImportExport.php
+++ b/lib/API/Endpoints/ImportExport.php
@@ -1,5 +1,7 @@
 <?php
 namespace MailPoet\API\Endpoints;
+use \MailPoet\API\Endpoint as APIEndpoint;
+use \MailPoet\API\Error as APIError;
 
 use MailPoet\Subscribers\ImportExport\Import\MailChimp;
 use MailPoet\Models\CustomField;
@@ -7,42 +9,69 @@ use MailPoet\Models\Segment;
 
 if(!defined('ABSPATH')) exit;
 
-class ImportExport {
+class ImportExport extends APIEndpoint {
   function getMailChimpLists($data) {
-    $mailChimp = new MailChimp($data['api_key']);
-    return $mailChimp->getLists();
+    try {
+      $mailChimp = new MailChimp($data['api_key']);
+      $lists = $mailChimp->getLists();
+      return $this->successResponse($lists);
+    } catch(\Exception $e) {
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
   }
 
   function getMailChimpSubscribers($data) {
-    $mailChimp = new MailChimp($data['api_key']);
-    return $mailChimp->getSubscribers($data['lists']);
+    try {
+      $mailChimp = new MailChimp($data['api_key']);
+      $subscribers = $mailChimp->getSubscribers($data['lists']);
+      return $this->successResponse($subscribers);
+   } catch(\Exception $e) {
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
   }
 
   function addSegment($data) {
     $segment = Segment::createOrUpdate($data);
-    return (
-      ($segment->id) ?
-        array(
-          'result' => true,
-          'segment' => $segment->asArray()
-        ) :
-        array(
-          'result' => false
-        )
-    );
+    $errors = $segment->getErrors();
+
+    if(!empty($errors)) {
+      return $this->errorResponse($errors);
+    } else {
+      return $this->successResponse(
+        Segment::findOne($segment->id)->asArray()
+      );
+    }
   }
 
   function processImport($data) {
-    $import = new \MailPoet\Subscribers\ImportExport\Import\Import(
-      json_decode($data, true)
-    );
-    return $import->process();
+    try {
+      $import = new \MailPoet\Subscribers\ImportExport\Import\Import(
+        json_decode($data, true)
+      );
+      $process = $import->process();
+      return $this->successResponse($process);
+    } catch(\Exception $e) {
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
   }
 
   function processExport($data) {
-    $export = new \MailPoet\Subscribers\ImportExport\Export\Export(
-      json_decode($data, true)
-    );
-    return $export->process();
+    try {
+      $export = new \MailPoet\Subscribers\ImportExport\Export\Export(
+        json_decode($data, true)
+      );
+      $process = $export->process();
+      return $this->successResponse($process);
+    } catch(\Exception $e) {
+      return $this->errorResponse(array(
+        $e->getCode() => $e->getMessage()
+      ));
+    }
   }
 }
\ No newline at end of file
diff --git a/lib/Subscribers/ImportExport/Import/Import.php b/lib/Subscribers/ImportExport/Import/Import.php
index 1639fdb619..0dea607aae 100644
--- a/lib/Subscribers/ImportExport/Import/Import.php
+++ b/lib/Subscribers/ImportExport/Import/Import.php
@@ -19,7 +19,6 @@ class Import {
   public $subscribers_count;
   public $created_at;
   public $updated_at;
-  public $profiler_start;
 
   public function __construct($data) {
     $this->subscribers_data = $this->transformSubscribersData(
@@ -40,7 +39,6 @@ class Import {
     $this->subscribers_count = count(reset($this->subscribers_data));
     $this->created_at = date('Y-m-d H:i:s', (int)$data['timestamp']);
     $this->updated_at = date('Y-m-d H:i:s', (int)$data['timestamp'] + 1);
-    $this->profiler_start = microtime(true);
   }
 
   function getSubscriberFieldsValidationRules($subscriber_fields) {
@@ -92,10 +90,7 @@ class Import {
         }
       }
     } catch(\PDOException $e) {
-      return array(
-        'result' => false,
-        'errors' => array($e->getMessage())
-      );
+      throw new \Exception($e->getMessage());
     }
     $import_factory = new ImportExportFactory('import');
     $segments = $import_factory->getSegments();
@@ -104,15 +99,11 @@ class Import {
         Newsletter::getWelcomeNotificationsForSegments($this->segments) :
         false;
     return array(
-      'result' => true,
-      'data' => array(
-        'created' => count($created_subscribers),
-        'updated' => count($updated_subscribers),
-        'segments' => $segments,
-        'added_to_segment_with_welcome_notification' =>
-          ($welcome_notifications_in_segments) ? true : false
-      ),
-      'profiler' => $this->timeExecution()
+      'created' => count($created_subscribers),
+      'updated' => count($updated_subscribers),
+      'segments' => $segments,
+      'added_to_segment_with_welcome_notification' =>
+        ($welcome_notifications_in_segments) ? true : false
     );
   }
 
@@ -415,9 +406,4 @@ class Import {
       );
     }
   }
-
-  function timeExecution() {
-    $profiler_end = microtime(true);
-    return ($profiler_end - $this->profiler_start) / 60;
-  }
 }
diff --git a/lib/Subscribers/ImportExport/Import/MailChimp.php b/lib/Subscribers/ImportExport/Import/MailChimp.php
index 1aae5c4377..f5491b8d1f 100644
--- a/lib/Subscribers/ImportExport/Import/MailChimp.php
+++ b/lib/Subscribers/ImportExport/Import/MailChimp.php
@@ -14,13 +14,13 @@ class MailChimp {
 
   function getLists() {
     if(!$this->api_key || !$this->data_center) {
-      return $this->processError('API');
+      return $this->throwException('API');
     }
 
     $connection = @fopen(sprintf($this->lists_url, $this->data_center, $this->api_key), 'r');
 
     if(!$connection) {
-      return $this->processError('connection');
+      return $this->throwException('connection');
     } else {
       $response = '';
       while(!feof($connection)) {
@@ -35,7 +35,7 @@ class MailChimp {
     $response = json_decode($response);
 
     if(!$response) {
-      return $this->processError('API');
+      return $this->throwException('API');
     }
 
     foreach($response->data as $list) {
@@ -45,19 +45,16 @@ class MailChimp {
       );
     }
 
-    return array(
-      'result' => true,
-      'data' => $lists
-    );
+    return $lists;
   }
 
   function getSubscribers($lists = array()) {
     if(!$this->api_key || !$this->data_center) {
-      return $this->processError('API');
+      return $this->throwException('API');
     }
 
     if(!$lists) {
-      return $this->processError('lists');
+      return $this->throwException('lists');
     }
 
     $bytes_fetched = 0;
@@ -65,7 +62,7 @@ class MailChimp {
       $url = sprintf($this->export_url, $this->data_center, $this->api_key, $list);
       $connection = @fopen($url, 'r');
       if(!$connection) {
-        return $this->processError('connection');
+        return $this->throwException('connection');
       }
       $i = 0;
       $header = array();
@@ -76,13 +73,13 @@ class MailChimp {
           if($i === 0) {
             $header = $obj;
             if(is_object($header) && isset($header->error)) {
-              return $this->processError('lists');
+              return $this->throwException('lists');
             }
             if(!isset($header_hash)) {
               $header_hash = md5(implode(',', $header));
             } else {
               if(md5(implode(',', $header) !== $header_hash)) {
-                return $this->processError('headers');
+                return $this->throwException('headers');
               }
             }
           } else {
@@ -92,25 +89,22 @@ class MailChimp {
         }
         $bytes_fetched += strlen($buffer);
         if($bytes_fetched > $this->max_post_size) {
-          return $this->processError('size');
+          return $this->throwException('size');
         }
       }
       fclose($connection);
     }
 
     if(!count($subscribers)) {
-      return $this->processError('subscribers');
+      return $this->throwException('subscribers');
     }
 
     return array(
-      'result' => true,
-      'data' => array(
-        'subscribers' => $subscribers,
-        'invalid' => false,
-        'duplicate' => false,
-        'header' => $header,
-        'subscribersCount' => count($subscribers)
-      )
+      'subscribers' => $subscribers,
+      'invalid' => false,
+      'duplicate' => false,
+      'header' => $header,
+      'subscribersCount' => count($subscribers)
     );
   }
 
@@ -125,7 +119,7 @@ class MailChimp {
     return (preg_match('/[a-zA-Z0-9]{32}-[a-zA-Z0-9]{3,}/', $APIKey)) ? $APIKey : false;
   }
 
-  function processError($error) {
+  function throwException($error) {
     switch($error) {
       case 'API':
         $errorMessage = __('Invalid API Key.');
@@ -146,9 +140,6 @@ class MailChimp {
         $errorMessage = __('Did not find any valid lists');
         break;
     }
-    return array(
-      'result' => false,
-      'errors' => array($errorMessage)
-    );
+    throw new \Exception($errorMessage);
   }
 }