diff --git a/application/PluginManager.php b/application/plugin/PluginManager.php
similarity index 87%
rename from application/PluginManager.php
rename to application/plugin/PluginManager.php
index 1ed4db4..f7b24a8 100644
--- a/application/PluginManager.php
+++ b/application/plugin/PluginManager.php
@@ -1,4 +1,8 @@
 <?php
+namespace Shaarli\Plugin;
+
+use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\Exception\PluginFileNotFoundException;
 
 /**
  * Class PluginManager
@@ -9,12 +13,14 @@ class PluginManager
 {
     /**
      * List of authorized plugins from configuration file.
+     *
      * @var array $authorizedPlugins
      */
     private $authorizedPlugins;
 
     /**
      * List of loaded plugins.
+     *
      * @var array $loadedPlugins
      */
     private $loadedPlugins = array();
@@ -31,12 +37,14 @@ class PluginManager
 
     /**
      * Plugins subdirectory.
+     *
      * @var string $PLUGINS_PATH
      */
     public static $PLUGINS_PATH = 'plugins';
 
     /**
      * Plugins meta files extension.
+     *
      * @var string $META_EXT
      */
     public static $META_EXT = 'meta';
@@ -84,9 +92,9 @@ class PluginManager
     /**
      * Execute all plugins registered hook.
      *
-     * @param string        $hook   name of the hook to trigger.
-     * @param array         $data   list of data to manipulate passed by reference.
-     * @param array         $params additional parameters such as page target.
+     * @param string $hook   name of the hook to trigger.
+     * @param array  $data   list of data to manipulate passed by reference.
+     * @param array  $params additional parameters such as page target.
      *
      * @return void
      */
@@ -118,7 +126,7 @@ class PluginManager
      * @param string $pluginName plugin's name.
      *
      * @return void
-     * @throws PluginFileNotFoundException - plugin files not found.
+     * @throws \Shaarli\Plugin\Exception\PluginFileNotFoundException - plugin files not found.
      */
     private function loadPlugin($dir, $pluginName)
     {
@@ -204,8 +212,8 @@ class PluginManager
 
                 $metaData[$plugin]['parameters'][$param]['value'] = '';
                 // Optional parameter description in parameter.PARAM_NAME=
-                if (isset($metaData[$plugin]['parameter.'. $param])) {
-                    $metaData[$plugin]['parameters'][$param]['desc'] = t($metaData[$plugin]['parameter.'. $param]);
+                if (isset($metaData[$plugin]['parameter.' . $param])) {
+                    $metaData[$plugin]['parameters'][$param]['desc'] = t($metaData[$plugin]['parameter.' . $param]);
                 }
             }
         }
@@ -223,22 +231,3 @@ class PluginManager
         return $this->errors;
     }
 }
-
-/**
- * Class PluginFileNotFoundException
- *
- * Raise when plugin files can't be found.
- */
-class PluginFileNotFoundException extends Exception
-{
-    /**
-     * Construct exception with plugin name.
-     * Generate message.
-     *
-     * @param string $pluginName name of the plugin not found
-     */
-    public function __construct($pluginName)
-    {
-        $this->message = sprintf(t('Plugin "%s" files not found.'), $pluginName);
-    }
-}
diff --git a/application/plugin/exception/PluginFileNotFoundException.php b/application/plugin/exception/PluginFileNotFoundException.php
new file mode 100644
index 0000000..e5386f0
--- /dev/null
+++ b/application/plugin/exception/PluginFileNotFoundException.php
@@ -0,0 +1,23 @@
+<?php
+namespace Shaarli\Plugin\Exception;
+
+use Exception;
+
+/**
+ * Class PluginFileNotFoundException
+ *
+ * Raise when plugin files can't be found.
+ */
+class PluginFileNotFoundException extends Exception
+{
+    /**
+     * Construct exception with plugin name.
+     * Generate message.
+     *
+     * @param string $pluginName name of the plugin not found
+     */
+    public function __construct($pluginName)
+    {
+        $this->message = sprintf(t('Plugin "%s" files not found.'), $pluginName);
+    }
+}
diff --git a/composer.json b/composer.json
index c1f4731..a2df466 100644
--- a/composer.json
+++ b/composer.json
@@ -46,6 +46,8 @@
             "Shaarli\\Feed\\": "application/feed",
             "Shaarli\\Http\\": "application/http",
             "Shaarli\\Netscape\\": "application/netscape",
+            "Shaarli\\Plugin\\": "application/plugin",
+            "Shaarli\\Plugin\\Exception\\": "application/plugin/exception",
             "Shaarli\\Render\\": "application/render",
             "Shaarli\\Security\\": "application/security",
             "Shaarli\\Updater\\": "application/updater",
diff --git a/index.php b/index.php
index bff8e8f..633ab89 100644
--- a/index.php
+++ b/index.php
@@ -65,7 +65,6 @@ require_once 'application/updater/UpdaterUtils.php';
 require_once 'application/FileUtils.php';
 require_once 'application/TimeZone.php';
 require_once 'application/Utils.php';
-require_once 'application/PluginManager.php';
 
 use \Shaarli\ApplicationUtils;
 use \Shaarli\Bookmark\Exception\LinkNotFoundException;
@@ -76,6 +75,7 @@ use \Shaarli\Feed\FeedBuilder;
 use \Shaarli\History;
 use \Shaarli\Languages;
 use \Shaarli\Netscape\NetscapeBookmarkUtils;
+use \Shaarli\Plugin\PluginManager;
 use \Shaarli\Render\PageBuilder;
 use \Shaarli\Render\ThemeUtils;
 use \Shaarli\Router;
diff --git a/plugins/archiveorg/archiveorg.php b/plugins/archiveorg/archiveorg.php
index 5dcea5a..0ee1c73 100644
--- a/plugins/archiveorg/archiveorg.php
+++ b/plugins/archiveorg/archiveorg.php
@@ -5,6 +5,8 @@
  * Add an icon in the link list for archive.org.
  */
 
+use Shaarli\Plugin\PluginManager;
+
 /**
  * Add archive.org icon to link_plugin when rendering linklist.
  *
diff --git a/plugins/demo_plugin/demo_plugin.php b/plugins/demo_plugin/demo_plugin.php
index 94ce38f..95ea7fe 100644
--- a/plugins/demo_plugin/demo_plugin.php
+++ b/plugins/demo_plugin/demo_plugin.php
@@ -15,6 +15,7 @@
  */
 
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /**
diff --git a/plugins/isso/isso.php b/plugins/isso/isso.php
index 9bdd590..dab75dd 100644
--- a/plugins/isso/isso.php
+++ b/plugins/isso/isso.php
@@ -5,6 +5,7 @@
  */
 
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /**
diff --git a/plugins/markdown/markdown.php b/plugins/markdown/markdown.php
index 9928a48..628970d 100644
--- a/plugins/markdown/markdown.php
+++ b/plugins/markdown/markdown.php
@@ -7,6 +7,7 @@
  */
 
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /*
diff --git a/plugins/piwik/piwik.php b/plugins/piwik/piwik.php
index ca00c2b..17b1aec 100644
--- a/plugins/piwik/piwik.php
+++ b/plugins/piwik/piwik.php
@@ -4,6 +4,8 @@
  * Adds tracking code on each page.
  */
 
+use Shaarli\Plugin\PluginManager;
+
 /**
  * Initialization function.
  * It will be called when the plugin is loaded.
diff --git a/plugins/playvideos/playvideos.php b/plugins/playvideos/playvideos.php
index bb5b9e9..0341ed5 100644
--- a/plugins/playvideos/playvideos.php
+++ b/plugins/playvideos/playvideos.php
@@ -6,6 +6,7 @@
  * Note: this plugin adds jQuery.
  */
 
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /**
diff --git a/plugins/pubsubhubbub/pubsubhubbub.php b/plugins/pubsubhubbub/pubsubhubbub.php
index a7bd34c..2878c05 100644
--- a/plugins/pubsubhubbub/pubsubhubbub.php
+++ b/plugins/pubsubhubbub/pubsubhubbub.php
@@ -12,6 +12,7 @@
 use pubsubhubbub\publisher\Publisher;
 use Shaarli\Config\ConfigManager;
 use Shaarli\Feed\FeedBuilder;
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /**
diff --git a/plugins/qrcode/qrcode.php b/plugins/qrcode/qrcode.php
index 21908ce..34eef8b 100644
--- a/plugins/qrcode/qrcode.php
+++ b/plugins/qrcode/qrcode.php
@@ -5,6 +5,7 @@
  * Display a QRCode icon in link list.
  */
 
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 /**
diff --git a/plugins/wallabag/wallabag.php b/plugins/wallabag/wallabag.php
index a6476c7..5ba1611 100644
--- a/plugins/wallabag/wallabag.php
+++ b/plugins/wallabag/wallabag.php
@@ -6,6 +6,7 @@
 
 require_once 'WallabagInstance.php';
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 
 /**
  * Init function, return an error if the server is not set.
diff --git a/tests/PluginManagerTest.php b/tests/PluginManagerTest.php
index 01de959..71761ac 100644
--- a/tests/PluginManagerTest.php
+++ b/tests/PluginManagerTest.php
@@ -1,16 +1,12 @@
 <?php
+namespace Shaarli\Plugin;
+
 use Shaarli\Config\ConfigManager;
 
-/**
- * Plugin Manager tests
- */
-
-require_once 'application/PluginManager.php';
-
 /**
  * Unit tests for Plugins
  */
-class PluginManagerTest extends PHPUnit_Framework_TestCase
+class PluginManagerTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * Path to tests plugin.
diff --git a/tests/plugins/PluginAddlinkTest.php b/tests/plugins/PluginAddlinkTest.php
index f6fea7a..e0a0107 100644
--- a/tests/plugins/PluginAddlinkTest.php
+++ b/tests/plugins/PluginAddlinkTest.php
@@ -1,19 +1,14 @@
 <?php
 
-/**
- * PluginPlayvideosTest.php
- */
-
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 require_once 'plugins/addlink_toolbar/addlink_toolbar.php';
-require_once 'application/Router.php';
 
 /**
- * Class PluginAddlinkTest
  * Unit test for the Addlink toolbar plugin
  */
-class PluginAddlinkTest extends PHPUnit_Framework_TestCase
+class PluginAddlinkTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * Reset plugin path.
diff --git a/tests/plugins/PluginArchiveorgTest.php b/tests/plugins/PluginArchiveorgTest.php
index fecd5f2..d06bfa5 100644
--- a/tests/plugins/PluginArchiveorgTest.php
+++ b/tests/plugins/PluginArchiveorgTest.php
@@ -4,6 +4,8 @@
  * PluginArchiveorgTest.php
  */
 
+use Shaarli\Plugin\PluginManager;
+
 require_once 'plugins/archiveorg/archiveorg.php';
 
 /**
diff --git a/tests/plugins/PluginIssoTest.php b/tests/plugins/PluginIssoTest.php
index f5fa1da..7aee219 100644
--- a/tests/plugins/PluginIssoTest.php
+++ b/tests/plugins/PluginIssoTest.php
@@ -2,6 +2,7 @@
 
 use Shaarli\Bookmark\LinkDB;
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 
 require_once 'plugins/isso/isso.php';
 
diff --git a/tests/plugins/PluginMarkdownTest.php b/tests/plugins/PluginMarkdownTest.php
index d695186..90a19e7 100644
--- a/tests/plugins/PluginMarkdownTest.php
+++ b/tests/plugins/PluginMarkdownTest.php
@@ -1,5 +1,6 @@
 <?php
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 
 /**
  * PluginMarkdownTest.php
diff --git a/tests/plugins/PluginPlayvideosTest.php b/tests/plugins/PluginPlayvideosTest.php
index 7ee9240..aa3ad14 100644
--- a/tests/plugins/PluginPlayvideosTest.php
+++ b/tests/plugins/PluginPlayvideosTest.php
@@ -4,6 +4,7 @@
  * PluginPlayvideosTest.php
  */
 
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 require_once 'plugins/playvideos/playvideos.php';
diff --git a/tests/plugins/PluginPubsubhubbubTest.php b/tests/plugins/PluginPubsubhubbubTest.php
index 75f146f..4680513 100644
--- a/tests/plugins/PluginPubsubhubbubTest.php
+++ b/tests/plugins/PluginPubsubhubbubTest.php
@@ -1,5 +1,6 @@
 <?php
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 require_once 'plugins/pubsubhubbub/pubsubhubbub.php';
diff --git a/tests/plugins/PluginQrcodeTest.php b/tests/plugins/PluginQrcodeTest.php
index 419965e..325e310 100644
--- a/tests/plugins/PluginQrcodeTest.php
+++ b/tests/plugins/PluginQrcodeTest.php
@@ -3,6 +3,7 @@
  * PluginQrcodeTest.php
  */
 
+use Shaarli\Plugin\PluginManager;
 use Shaarli\Router;
 
 require_once 'plugins/qrcode/qrcode.php';
diff --git a/tests/plugins/PluginWallabagTest.php b/tests/plugins/PluginWallabagTest.php
index 76b7887..4e445ef 100644
--- a/tests/plugins/PluginWallabagTest.php
+++ b/tests/plugins/PluginWallabagTest.php
@@ -1,5 +1,6 @@
 <?php
 use Shaarli\Config\ConfigManager;
+use Shaarli\Plugin\PluginManager;
 
 /**
  * PluginWallabagTest.php.php
@@ -11,7 +12,7 @@ require_once 'plugins/wallabag/wallabag.php';
  * Class PluginWallabagTest
  * Unit test for the Wallabag plugin
  */
-class PluginWallabagTest extends PHPUnit_Framework_TestCase
+class PluginWallabagTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * Reset plugin path