diff --git a/include/common.inc.php b/include/common.inc.php
index e40129c9f..d9b6f2420 100644
--- a/include/common.inc.php
+++ b/include/common.inc.php
@@ -253,6 +253,30 @@ if (isset($page['auth_key_invalid']) and $page['auth_key_invalid'])
     ;
 }
 
+// check if we need to notified user about api_key expiration
+if (isset($page['notify_api_key_expiration']) and is_array($page['notify_api_key_expiration']))
+{
+  $is_mail_send = notification_api_key_expiration(
+    $user['username'],
+    $user['email'],
+    $page['notify_api_key_expiration']['days_left']
+  );
+
+  if ($is_mail_send)
+  {
+    single_update(
+      USER_AUTH_KEYS_TABLE,
+      array('last_notified_on' => $page['notify_api_key_expiration']['dbnow']),
+      array(
+        'user_id' => $user['id'],
+        'auth_key' => $page['notify_api_key_expiration']['auth_key']
+      ),   
+    );
+  }
+
+  unset($page['notify_api_key_expiration']);
+}
+
 // template instance
 if (defined('IN_ADMIN') and IN_ADMIN )
 {// Admin template
diff --git a/include/functions_user.inc.php b/include/functions_user.inc.php
index ac19032c7..6ec16e686 100644
--- a/include/functions_user.inc.php
+++ b/include/functions_user.inc.php
@@ -1694,7 +1694,10 @@ function auth_key_login($auth_key, $connection_by_header=false)
 SELECT
     *,
     '.$conf['user_fields']['username'].' AS username,
-    NOW() AS dbnow
+    '.$conf['user_fields']['email'].' AS email,
+    NOW() AS dbnow,
+    DATEDIFF(uak.expired_on, NOW()) AS days_left,
+    SUBDATE(NOW(), INTERVAL 48 HOUR) AS 48h_ago
   FROM '.USER_AUTH_KEYS_TABLE.' AS uak
     JOIN '.USER_INFOS_TABLE.' AS ui ON uak.user_id = ui.user_id
     JOIN '.USERS_TABLE.' AS u ON u.'.$conf['user_fields']['id'].' = ui.user_id
@@ -1709,6 +1712,19 @@ SELECT
   
   $key = $keys[0];
 
+  // is the key still valid?
+  if (strtotime($key['expired_on']) < strtotime($key['dbnow']))
+  {
+    $page['auth_key_invalid'] = true;
+    return false;
+  }
+
+  // admin/webmaster/guest can't get connected with authentication keys
+  if ('auth_key' === $valid_key and !in_array($key['status'], array('normal','generic')))
+  {
+    return false;
+  }
+
   // the key is an api_key
   if ('api_key' === $valid_key)
   {
@@ -1723,19 +1739,24 @@ SELECT
     {
       return false;
     }
-  }
 
-  // is the key still valid?
-  if (strtotime($key['expired_on']) < strtotime($key['dbnow']))
-  {
-    $page['auth_key_invalid'] = true;
-    return false;
-  }
-
-  // admin/webmaster/guest can't get connected with authentication keys
-  if ('auth_key' === $valid_key and !in_array($key['status'], array('normal','generic')))
-  {
-    return false;
+    // check if we need to notificate the user
+    $days_left = intval($key['days_left']);
+    if (
+      $days_left <= 7 // the key expire in max 7 days
+      and !empty($key['email']) // the user have an email
+      and (
+        null === $key['last_notified_on'] // we never send an email for this key
+        or strtotime($key['last_notified_on']) < strtotime($key['48h_ago']) // OR when the last email was sent more than 48 hours ago
+      )
+    )
+    {
+      $page['notify_api_key_expiration'] = array(
+        'days_left' => $days_left,
+        'dbnow' => $key['dbnow'],
+        'auth_key' => $key['auth_key']
+      );
+    }
   }
 
   $user['id'] = $key['user_id'];
@@ -2655,4 +2676,36 @@ function connected_with_pwg_ui()
   }
   return false;
 }
+
+/**
+ * Notify an user when his api key is about to expire
+ *
+ * @since 16
+ * @return bool
+ */
+function notification_api_key_expiration($username, $email, $days_left)
+{
+  global $conf;
+
+  include_once(PHPWG_ROOT_PATH . 'include/functions_mail.inc.php');
+  $days_left_str = $days_left <= 1 ? 
+    l10n('Your API key will expire in %d day.', $days_left)
+    : l10n('Your API key will expire in %d days.', $days_left);
+
+  $message = '<p style="margin: 20px 0">' . l10n('Hello %s,', $username) . '</p>';
+  $message .= '<p style="margin: 20px 0">' . $days_left_str . '</p>';
+  $message .= '<p style="margin: 20px 0">' . l10n('To continue using the API, please renew your key before it expires.') . '</p>';
+  $message .= '<p style="margin: 20px 0">' . l10n('You can manage your API keys in your <a href="%s">account settings.</a>', get_absolute_root_url().'profile.php') . '</p>';
+
+  $result = @pwg_mail(
+    $email,
+    array(
+      'subject' => '[' . $conf['gallery_title'] . '] ' . l10n('Your API key will expire soon'),
+      'content' => $message,
+      'content_format' => 'text/html',
+    )
+  );
+
+  return $result;
+}
 ?>
diff --git a/install/db/179-database.php b/install/db/179-database.php
new file mode 100644
index 000000000..bb9eb8407
--- /dev/null
+++ b/install/db/179-database.php
@@ -0,0 +1,24 @@
+<?php
+// +-----------------------------------------------------------------------+
+// | This file is part of Piwigo.                                          |
+// |                                                                       |
+// | For copyright and license information, please view the COPYING.txt    |
+// | file that was distributed with this source code.                      |
+// +-----------------------------------------------------------------------+
+
+if (!defined('PHPWG_ROOT_PATH'))
+{
+  die('Hacking attempt!');
+}
+
+$upgrade_description = 'Modification to the user_auth_key table to add last_notified_on';
+
+// For API KEY, add a column last_notified_on, to know when the last email (for the moment)
+// notifying of an upcoming expiration date was sent.
+pwg_query(
+'ALTER TABLE `'.PREFIX_TABLE.'user_auth_keys` 
+  ADD COLUMN `last_notified_on` datetime DEFAULT NULL
+;');
+
+echo "\n".$upgrade_description."\n";
+?>
\ No newline at end of file
diff --git a/language/en_UK/common.lang.php b/language/en_UK/common.lang.php
index 441599f9f..7fbc3af55 100644
--- a/language/en_UK/common.lang.php
+++ b/language/en_UK/common.lang.php
@@ -518,3 +518,8 @@ $lang['Do you really want to revoke the "%s" API key?'] = 'Do you really want to
 $lang['To manage your API keys, please log in with your username/password.'] = 'To manage your API keys, please log in with your username/password.';
 $lang['3xlarge'] = '3XL - extra huge';
 $lang['4xlarge'] = '4XL - gigantic';
+$lang['Your API key will expire soon'] = 'Your API key will expire soon';
+$lang['Your API key will expire in %d day.'] = 'Your API key will expire in %d day.';
+$lang['Your API key will expire in %d days.'] = 'Your API key will expire in %d days.';
+$lang['To continue using the API, please renew your key before it expires.'] = 'To continue using the API, please renew your key before it expires.';
+$lang['You can manage your API keys in your <a href="%s">account settings.</a>'] = 'You can manage your API keys in your <a href="%s">account settings.</a>';
diff --git a/language/fr_FR/common.lang.php b/language/fr_FR/common.lang.php
index f139b2c5e..79a0e6cc5 100644
--- a/language/fr_FR/common.lang.php
+++ b/language/fr_FR/common.lang.php
@@ -517,3 +517,8 @@ $lang['Do you really want to revoke the "%s" API key?'] = 'Voulez-vous vraiment
 $lang['To manage your API keys, please log in with your username/password.'] = 'Pour gérer vos clés API, veuillez vous connecter avec votre nom d\'utilisateur/mot de passe.';
 $lang['3xlarge'] = '3XL - très énorme';
 $lang['4xlarge'] = '4XL - gigantesque';
+$lang['Your API key will expire soon'] = 'Votre clé API va bientôt expirer';
+$lang['Your API key will expire in %d day.'] = 'Votre clé API expirera dans %d jour.';
+$lang['Your API key will expire in %d days.'] = 'Votre clé API expirera dans %d jours.';
+$lang['To continue using the API, please renew your key before it expires.'] = 'Pour continuer à utiliser l\'API, veuillez renouveler votre clé avant son expiration.';
+$lang['You can manage your API keys in your <a href="%s">account settings.</a>'] = 'Vous pouvez gérer vos clés API dans les <a href="%s">paramètres de votre compte.</a>';