diff --git a/includes/class-wp-notify-aggregate-factory.php b/includes/class-aggregate-factory.php
similarity index 96%
rename from includes/class-wp-notify-aggregate-factory.php
rename to includes/class-aggregate-factory.php
index 22343a5e..8a23d541 100644
--- a/includes/class-wp-notify-aggregate-factory.php
+++ b/includes/class-aggregate-factory.php
@@ -1,6 +1,8 @@
 <?php
 
-abstract class WP_Notify_Aggregate_Factory {
+namespace WP\Notifications;
+
+abstract class Aggregate_Factory {
 
 	/**
 	 * Array of factories that this aggregate factory represents.
diff --git a/includes/class-wp-notify-base-notification.php b/includes/class-base-notification.php
similarity index 67%
rename from includes/class-wp-notify-base-notification.php
rename to includes/class-base-notification.php
index 0cc21018..a797345f 100644
--- a/includes/class-wp-notify-base-notification.php
+++ b/includes/class-base-notification.php
@@ -1,6 +1,13 @@
 <?php
 
-class WP_Notify_Base_Notification implements WP_Notify_Notification {
+namespace WP\Notifications;
+
+use ReflectionClass;
+use WP\Notifications\Messages;
+use WP\Notifications\Recipients;
+use WP\Notifications\Senders;
+
+class Base_Notification implements Notification {
 
 	/**
 	 * ID of the notification.
@@ -12,7 +19,7 @@ class WP_Notify_Base_Notification implements WP_Notify_Notification {
 	/**
 	 * Sender of the notification.
 	 *
-	 * @var WP_Notify_Sender
+	 * @var Senders\Sender
 	 */
 	protected $sender;
 
@@ -26,14 +33,14 @@ class WP_Notify_Base_Notification implements WP_Notify_Notification {
 	/**
 	 * Collection of notification recipients.
 	 *
-	 * @var WP_Notify_Recipient_Collection
+	 * @var Recipients\Collection
 	 */
 	protected $recipients;
 
 	/**
 	 * Notification message.
 	 *
-	 * @var WP_Notify_Message
+	 * @var Messages\Message
 	 */
 	protected $message;
 
@@ -42,31 +49,22 @@ class WP_Notify_Base_Notification implements WP_Notify_Notification {
 	 *
 	 * @var string
 	 */
-	protected $status = WP_Notify_Status::UNREAD;
+	protected $status = Status::UNREAD;
 
 	/**
-	 * Instantiates a WPNotify_Base_Notification object.
+	 * Instantiates a Base_Notification object.
 	 *
-	 * @param WP_Notify_Sender               $sender     Sender that sent the
-	 *                                                  notification.
-	 * @param WP_Notify_Recipient_Collection $recipients Recipients that should
-	 *                                                 receive the
-	 *                                                 notification.
-	 * @param WP_Notify_Message              $message    Message of the
-	 *                                                  notification.
-	 * @param mixed                          $timestamp  Optional. Timestamp of
-	 *                                                   when the notification
-	 *                                                   was triggered. Defaults
-	 *                                                   to the moment of
-	 *                                                   instantiation.
-	 * @param int                            $id         Optional. ID of the
-	 *                                                   notification. Defaults
-	 *                                                   to -1.
+	 * @param Senders\Sender        $sender     Sender that sent the notification.
+	 * @param Recipients\Collection $recipients Recipients that should receive the notification.
+	 * @param Messages\Message      $message    Message of the notification.
+	 * @param mixed                 $timestamp  Optional. Timestamp of when the notification was
+	 *                                          triggered. Defaults to the moment of instantiation.
+	 * @param int                   $id         Optional. ID of the notification. Defaults to -1.
 	 */
 	public function __construct(
-		WP_Notify_Sender $sender,
-		WP_Notify_Recipient_Collection $recipients,
-		WP_Notify_Message $message,
+		Senders\Sender $sender,
+		Recipients\Collection $recipients,
+		Messages\Message $message,
 		$timestamp = null,
 		$id = - 1
 	) {
@@ -113,7 +111,7 @@ protected function validate_timestamp( $timestamp ) {
 	/**
 	 * Get the sender of the notification.
 	 *
-	 * @return WP_Notify_Sender Sender of the notification.
+	 * @return Senders\Sender Sender of the notification.
 	 */
 	public function get_sender() {
 		return $this->sender;
@@ -122,7 +120,7 @@ public function get_sender() {
 	/**
 	 * Gets the recipients for the notification.
 	 *
-	 * @return WP_Notify_Recipient_Collection Notification recipients.
+	 * @return Recipients\Collection Notification recipients.
 	 */
 	public function get_recipients() {
 		return $this->recipients;
@@ -131,7 +129,7 @@ public function get_recipients() {
 	/**
 	 * Gets the message for the notification.
 	 *
-	 * @return WP_Notify_Message Notification message.
+	 * @return Messages\Message Notification message.
 	 */
 	public function get_message() {
 		return $this->message;
diff --git a/includes/class-wp-notify-factory.php b/includes/class-factory.php
similarity index 77%
rename from includes/class-wp-notify-factory.php
rename to includes/class-factory.php
index 53e540e3..8774731c 100644
--- a/includes/class-wp-notify-factory.php
+++ b/includes/class-factory.php
@@ -1,6 +1,12 @@
 <?php
 
-class WP_Notify_Factory {
+namespace WP\Notifications;
+
+use WP\Notifications\Messages;
+use WP\Notifications\Recipients;
+use WP\Notifications\Senders;
+
+class Factory {
 
 	const MESSAGE    = 'message';
 	const RECIPIENTS = 'recipients';
@@ -8,28 +14,28 @@ class WP_Notify_Factory {
 	/**
 	 * Message factory implementation to use.
 	 *
-	 * @var WP_Notify_Message_Factory
+	 * @var Messages\Factory
 	 */
 	private $message_factory;
 
 	/**
 	 * Recipient factory implementation to use.
 	 *
-	 * @var WP_Notify_Recipient_Factory
+	 * @var Recipients\Factory
 	 */
 	private $recipient_factory;
 
 	/**
 	 * Sender factory implementation to use
 	 *
-	 * @var WP_Notify_Sender_Factory
+	 * @var Senders\Factory
 	 */
 	private $sender_factory;
 
 	public function __construct(
-		WP_Notify_Message_Factory $message_factory,
-		WP_Notify_Recipient_Factory $recipient_factory,
-		WP_Notify_Sender_Factory $sender_factory
+		Messages\Factory $message_factory,
+		Recipients\Factory $recipient_factory,
+		Senders\Factory $sender_factory
 	) {
 		$this->message_factory   = $message_factory;
 		$this->recipient_factory = $recipient_factory;
@@ -41,14 +47,14 @@ public function __construct(
 	 *
 	 * @param $args
 	 *
-	 * @return WP_Notify_Base_Notification
+	 * @return Base_Notification
 	 */
 	public function create( $args ) {
 
 		list( $message_args, $recipients_args, $sender_args ) = $this->validate( $args );
 
 		$sender     = $this->sender_factory->create( $sender_args );
-		$recipients = new WP_Notify_Recipient_Collection();
+		$recipients = new Recipients\Collection();
 		$message    = $this->message_factory->create( $message_args );
 
 		foreach ( $recipients_args as $type => $value ) {
@@ -57,7 +63,7 @@ public function create( $args ) {
 			);
 		}
 
-		return new WP_Notify_Base_Notification( $sender, $recipients, $message );
+		return new Base_Notification( $sender, $recipients, $message );
 	}
 
 	private function validate( $args ) {
diff --git a/includes/demo.php b/includes/demo.php
index 9de24668..d28bc33f 100644
--- a/includes/demo.php
+++ b/includes/demo.php
@@ -5,12 +5,17 @@
  * Development demo files
  **/
 
+namespace WP\Notifications;
+
+use WP_Admin_Bar;
+use WP_List_Table;
+
 /**
  * Adds WP Notify icon after the user avatar in the top admin bar in the "secondary" position
  *
  * @param WP_Admin_Bar $wp_admin_bar Toolbar instance.
  */
-function wp_admin_bar_wp_notify_item( WP_Admin_Bar $wp_admin_bar ) {
+function admin_bar_item( WP_Admin_Bar $wp_admin_bar ) {
 	if ( ! is_admin() ) {
 		return;
 	}
@@ -36,27 +41,27 @@ function wp_admin_bar_wp_notify_item( WP_Admin_Bar $wp_admin_bar ) {
 	);
 	$wp_admin_bar->add_node( $args );
 }
-add_action( 'admin_bar_menu', 'wp_admin_bar_wp_notify_item', 1 );
+add_action( 'admin_bar_menu', '\WP\Notifications\admin_bar_item', 1 );
 
 /**
  * Adds WP Notify area at the top of the dashboard
  */
-function wp_notify_admin_notice() {
+function admin_notice() {
 	echo '<div id="wp-notify-dashboard" class="wrap"></div>';
 }
-add_action( 'admin_notices', 'wp_notify_admin_notice' );
+add_action( 'admin_notices', '\WP\Notifications\admin_notice' );
 
 /**
  * Register and enqueue a wp notify scripts and stylesheet in WordPress admin.
  */
-function wp_notify_enqueue_admin_assets() {
+function enqueue_admin_assets() {
 	/* Load styles */
-	wp_register_style( 'wp_notify_css', WP_NOTIFICATION_CENTER_PLUGIN_DIR_URL . '/build/wp-notify.css', array(), WP_NOTIFICATION_CENTER_PLUGIN_VERSION );
+	wp_register_style( 'wp_notify_css', WP_FEATURE_NOTIFICATION_PLUGIN_DIR_URL . '/build/wp-notify.css', array(), WP_FEATURE_NOTIFICATION_PLUGIN_VERSION );
 	wp_enqueue_style( 'wp_notify_css' );
 
 	/* Load scripts */
-	$asset = include WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/build/wp-notify.asset.php';
-	wp_register_script( 'wp_notify_js', WP_NOTIFICATION_CENTER_PLUGIN_DIR_URL . '/build/wp-notify.js', $asset['dependencies'], WP_NOTIFICATION_CENTER_PLUGIN_VERSION, true );
+	$asset = include WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/build/wp-notify.asset.php';
+	wp_register_script( 'wp_notify_js', WP_FEATURE_NOTIFICATION_PLUGIN_DIR_URL . '/build/wp-notify.js', $asset['dependencies'], WP_FEATURE_NOTIFICATION_PLUGIN_VERSION, true );
 	wp_enqueue_script( 'wp_notify_js' );
 	wp_localize_script(
 		'wp_notify_js',
@@ -67,7 +72,7 @@ function wp_notify_enqueue_admin_assets() {
 	);
 }
 
-add_action( 'admin_enqueue_scripts', 'wp_notify_enqueue_admin_assets', 0 );
+add_action( 'admin_enqueue_scripts', '\WP\Notifications\enqueue_admin_assets', 0 );
 
 
 /**
@@ -75,17 +80,17 @@ function wp_notify_enqueue_admin_assets() {
  *
  * @return void
  */
-function wp_notify_add_admin_options_page() {
-	add_options_page( 'Notifications', 'Notifications', 'manage_options', 'wp-notify', 'wp_notify_render_admin_options_page' );
+function add_admin_options_page() {
+	add_options_page( 'Notifications', 'Notifications', 'manage_options', 'wp-notify', '\WP\Notifications\render_admin_options_page' );
 }
-add_action( 'admin_menu', 'wp_notify_add_admin_options_page' );
+add_action( 'admin_menu', '\WP\Notifications\add_admin_options_page' );
 
 
 
 /**
  * Renders the options page.
  */
-function wp_notify_render_admin_options_page() {    ?>
+function render_admin_options_page() {    ?>
 
 	<h1><?php _e( 'Notifications settings' ); ?></h1>
 
@@ -227,16 +232,16 @@ function init_table() {
 /**
  * Registers our dashboard widget.
  */
-function wp_notify_dashboard_widget() {
-	add_meta_box( 'wp_notify', __( 'WP Notify' ), 'wp_notify_render_dashboard_widget', 'dashboard', 'side', 'high' );
+function dashboard_widget() {
+	add_meta_box( 'wp_notify', __( 'WP Notify' ), '\WP\Notifications\render_dashboard_widget', 'dashboard', 'side', 'high' );
 }
-add_action( 'wp_dashboard_setup', 'wp_notify_dashboard_widget' );
+add_action( 'wp_dashboard_setup', '\WP\Notifications\dashboard_widget' );
 
 
 /**
  * Renders our dashboard widget.
  */
-function wp_notify_render_dashboard_widget() {
+function render_dashboard_widget() {
 	?>
 	<div id="wp-notification-metabox">
 		<form id="wp-notification-metabox-form" class="initial-form hide-if-no-js">
diff --git a/includes/exceptions/class-wp-notify-failed-to-add-recipient.php b/includes/exceptions/class-failed-to-add-recipient.php
similarity index 70%
rename from includes/exceptions/class-wp-notify-failed-to-add-recipient.php
rename to includes/exceptions/class-failed-to-add-recipient.php
index ca0836d7..11cc466b 100644
--- a/includes/exceptions/class-wp-notify-failed-to-add-recipient.php
+++ b/includes/exceptions/class-failed-to-add-recipient.php
@@ -1,6 +1,8 @@
 <?php
 
-class WP_Notify_Failed_To_Add_Recipient extends WP_Notify_Runtime_Exception {
+namespace WP\Notifications\Exceptions;
+
+class Failed_To_Add_Recipient extends Runtime_Exception {
 
 	public static function from_invalid_recipient(
 		$recipient
@@ -10,7 +12,7 @@ public static function from_invalid_recipient(
 		$message = sprintf(
 			/* translators: "%s" is a type of recipient. */
 			__(
-				'Failed to add invalid recipient type "%s" to recipient collection, only implementations of interface "WP_Notify_Recipient" allowed.',
+				'Failed to add invalid recipient type "%s" to recipient collection, only implementations of interface "Recipient" allowed.',
 				'wp-notification-center'
 			),
 			$type
diff --git a/includes/exceptions/class-wp-notify-invalid-recipient.php b/includes/exceptions/class-invalid-recipient.php
similarity index 85%
rename from includes/exceptions/class-wp-notify-invalid-recipient.php
rename to includes/exceptions/class-invalid-recipient.php
index e4d5dc9a..7975f157 100644
--- a/includes/exceptions/class-wp-notify-invalid-recipient.php
+++ b/includes/exceptions/class-invalid-recipient.php
@@ -1,6 +1,8 @@
 <?php
 
-class WP_Notify_Invalid_Recipient extends WP_Notify_Runtime_Exception {
+namespace WP\Notifications\Exceptions;
+
+class Invalid_Recipient extends Runtime_Exception {
 
 	public static function from_invalid_user_id( $user_id ) {
 		$type  = is_object( $user_id ) ? get_class( $user_id ) : gettype( $user_id );
diff --git a/includes/exceptions/class-wp-notify-invalid-type.php b/includes/exceptions/class-invalid-type.php
similarity index 87%
rename from includes/exceptions/class-wp-notify-invalid-type.php
rename to includes/exceptions/class-invalid-type.php
index 6e15b30b..aa442229 100644
--- a/includes/exceptions/class-wp-notify-invalid-type.php
+++ b/includes/exceptions/class-invalid-type.php
@@ -1,6 +1,8 @@
 <?php
 
-class WP_Notify_Invalid_Type extends WP_Notify_Runtime_Exception {
+namespace WP\Notifications\Exceptions;
+
+class Invalid_Type extends Runtime_Exception {
 
 	public static function from_message_type( $type ) {
 		$message = sprintf(
diff --git a/includes/exceptions/class-runtime-exception.php b/includes/exceptions/class-runtime-exception.php
new file mode 100644
index 00000000..dbfdcf97
--- /dev/null
+++ b/includes/exceptions/class-runtime-exception.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace WP\Notifications\Exceptions;
+
+class Runtime_Exception
+	extends \RuntimeException
+	implements Exception {
+
+}
diff --git a/includes/exceptions/class-wp-notify-runtime-exception.php b/includes/exceptions/class-wp-notify-runtime-exception.php
deleted file mode 100644
index 1696f652..00000000
--- a/includes/exceptions/class-wp-notify-runtime-exception.php
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-class WP_Notify_Runtime_Exception
-	extends RuntimeException
-	implements WP_Notify_Exception {
-
-}
diff --git a/includes/exceptions/interface-exception.php b/includes/exceptions/interface-exception.php
new file mode 100644
index 00000000..44a59b6b
--- /dev/null
+++ b/includes/exceptions/interface-exception.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace WP\Notifications\Exceptions;
+
+interface Exception {
+
+}
diff --git a/includes/exceptions/interface-wp-notify-exception.php b/includes/exceptions/interface-wp-notify-exception.php
deleted file mode 100644
index d28c2e8a..00000000
--- a/includes/exceptions/interface-wp-notify-exception.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-interface WP_Notify_Exception {
-
-}
diff --git a/includes/image/class-wp-notify-base-image.php b/includes/image/class-base-image.php
similarity index 89%
rename from includes/image/class-wp-notify-base-image.php
rename to includes/image/class-base-image.php
index a032289b..f2d94982 100644
--- a/includes/image/class-wp-notify-base-image.php
+++ b/includes/image/class-base-image.php
@@ -1,6 +1,8 @@
 <?php
 
-class WP_Notify_Base_Image implements WP_Notify_Image {
+namespace WP\Notifications\Image;
+
+class Base_Image implements Image {
 
 	/**
 	 * It can be and URL of an image file or and data/image source
@@ -62,11 +64,11 @@ public function get_alt() {
 	}
 
 	/**
-	 * Instantiates a WPNotify_BaseImage based on a JSON string
+	 * Instantiates a BaseImage based on a JSON string
 	 *
 	 * @param string $json
 	 *
-	 * @return WP_Notify_Json_Unserializable
+	 * @return Json_Unserializable
 	 */
 	public static function json_unserialize( $json ) {
 
diff --git a/includes/image/interface-image.php b/includes/image/interface-image.php
new file mode 100644
index 00000000..78d450ef
--- /dev/null
+++ b/includes/image/interface-image.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace WP\Notifications\Image;
+
+use JsonSerializable;
+
+use WP\Notifications;
+
+interface Image extends JsonSerializable, Notifications\Json_Unserializable {
+
+}
diff --git a/includes/image/interface-wp-notify-image.php b/includes/image/interface-wp-notify-image.php
deleted file mode 100644
index 7c8e2b52..00000000
--- a/includes/image/interface-wp-notify-image.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-interface WP_Notify_Image extends JsonSerializable, WP_Notify_Json_Unserializable {
-
-}
diff --git a/includes/interface-wp-notify-json-unserializable.php b/includes/interface-json-unserializable.php
similarity index 78%
rename from includes/interface-wp-notify-json-unserializable.php
rename to includes/interface-json-unserializable.php
index 5fa0b7bb..8a02f3e6 100644
--- a/includes/interface-wp-notify-json-unserializable.php
+++ b/includes/interface-json-unserializable.php
@@ -1,6 +1,8 @@
 <?php
 
-interface WP_Notify_Json_Unserializable {
+namespace WP\Notifications;
+
+interface Json_Unserializable {
 
 	/**
 	 * Creates a new instance from JSON-encoded data.
diff --git a/includes/interface-wp-notify-notification.php b/includes/interface-notification.php
similarity index 67%
rename from includes/interface-wp-notify-notification.php
rename to includes/interface-notification.php
index 8419c83c..354bfe42 100644
--- a/includes/interface-wp-notify-notification.php
+++ b/includes/interface-notification.php
@@ -1,6 +1,10 @@
 <?php
 
-interface WP_Notify_Notification extends JsonSerializable, WP_Notify_Json_Unserializable {
+namespace WP\Notifications;
+
+use JsonSerializable;
+
+interface Notification extends JsonSerializable, Json_Unserializable {
 
 	/**
 	 * Get the ID of the notification.
@@ -19,21 +23,21 @@ public function get_timestamp();
 	/**
 	 * Get the sender of the notification.
 	 *
-	 * @return WP_Notify_Sender Sender of the notification.
+	 * @return Sender Sender of the notification.
 	 */
 	public function get_sender();
 
 	/**
 	 * Get the recipients for the notification.
 	 *
-	 * @return WP_Notify_Recipient_Collection Notification recipients.
+	 * @return Recipient_Collection Notification recipients.
 	 */
 	public function get_recipients();
 
 	/**
 	 * Get the message for the notification.
 	 *
-	 * @return WP_Notify_Message Notification message.
+	 * @return Message Notification message.
 	 */
 	public function get_message();
 }
diff --git a/includes/interface-wp-notify-status.php b/includes/interface-status.php
similarity index 55%
rename from includes/interface-wp-notify-status.php
rename to includes/interface-status.php
index cb13ef24..27caaef6 100644
--- a/includes/interface-wp-notify-status.php
+++ b/includes/interface-status.php
@@ -1,6 +1,8 @@
 <?php
 
-interface WP_Notify_Status {
+namespace WP\Notifications;
+
+interface Status {
 
 	const UNREAD = 'unread';
 	const READ   = 'read';
diff --git a/includes/recipients/class-wp-notify-aggregate-recipient-factory.php b/includes/messages/class-aggregate-factory.php
similarity index 50%
rename from includes/recipients/class-wp-notify-aggregate-recipient-factory.php
rename to includes/messages/class-aggregate-factory.php
index e020b860..557d6980 100644
--- a/includes/recipients/class-wp-notify-aggregate-recipient-factory.php
+++ b/includes/messages/class-aggregate-factory.php
@@ -1,8 +1,12 @@
 <?php
 
-final class WP_Notify_Aggregate_Recipient_Factory
-	extends WP_Notify_Aggregate_Factory
-	implements WP_Notify_Recipient_Factory {
+namespace WP\Notifications\Messages;
+
+use WP\Notifications;
+
+final class Aggregate_Factory
+	extends Notifications\Aggregate_Factory
+	implements Factory {
 
 	/**
 	 * Get the interface that this aggregate factory can instantiate
@@ -11,6 +15,6 @@ final class WP_Notify_Aggregate_Recipient_Factory
 	 * @return string Class name of the interface.
 	 */
 	protected function get_interface() {
-		return 'WP_Notify_Recipient_Factory';
+		return '\WP\Notifications\Messages\Factory';
 	}
 }
diff --git a/includes/messages/class-wp-notify-base-message-factory.php b/includes/messages/class-base-factory.php
similarity index 79%
rename from includes/messages/class-wp-notify-base-message-factory.php
rename to includes/messages/class-base-factory.php
index 2c34b466..5fc699d1 100644
--- a/includes/messages/class-wp-notify-base-message-factory.php
+++ b/includes/messages/class-base-factory.php
@@ -1,6 +1,10 @@
 <?php
 
-class WP_Notify_Base_Message_Factory implements WP_Notify_Message_Factory {
+namespace WP\Notifications\Messages;
+
+use WP\Notifications\Exceptions;
+
+class Base_Factory implements Factory {
 
 	const TYPE_STANDARD = 'standard';
 
@@ -11,13 +15,13 @@ class WP_Notify_Base_Message_Factory implements WP_Notify_Message_Factory {
 	 * @param string $type  Optional. Type of the message. Defaults to
 	 *                      'standard'.
 	 *
-	 * @return WP_Notify_Message
+	 * @return Message
 	 *
-	 * @throws WP_Notify_Invalid_Type If the message type was not valid.
+	 * @throws Invalid_Type If the message type was not valid.
 	 */
 	public function create( $value, $type = 'standard' ) {
 		if ( ! $this->accepts( $type ) ) {
-			throw WP_Notify_Invalid_Type::from_message_type( $type );
+			throw Exceptions\Invalid_Type::from_message_type( $type );
 		}
 
 		list( $type, $value ) = $this->validate( $type, $value );
@@ -25,7 +29,7 @@ public function create( $value, $type = 'standard' ) {
 		switch ( $type ) {
 			case self::TYPE_STANDARD:
 			default:
-				return new WP_Notify_Base_Message( $value );
+				return new Base_Message( $value );
 		}
 	}
 
diff --git a/includes/messages/class-wp-notify-base-message.php b/includes/messages/class-base-message.php
similarity index 90%
rename from includes/messages/class-wp-notify-base-message.php
rename to includes/messages/class-base-message.php
index f0a55678..2300b3e3 100644
--- a/includes/messages/class-wp-notify-base-message.php
+++ b/includes/messages/class-base-message.php
@@ -1,6 +1,8 @@
 <?php
 
-class WP_Notify_Base_Message implements WP_Notify_Message {
+namespace WP\Notifications\Messages;
+
+class Base_Message implements Message {
 
 	/**
 	 * Message content.
@@ -10,7 +12,7 @@ class WP_Notify_Base_Message implements WP_Notify_Message {
 	protected $message;
 
 	/**
-	 * Instantiates a WPNotify_BaseMessage object.
+	 * Instantiates a BaseMessage object.
 	 *
 	 * @param string $message Message content.
 	 */
diff --git a/includes/messages/class-wp-notify-aggregate-message-factory.php b/includes/messages/class-wp-notify-aggregate-message-factory.php
deleted file mode 100644
index 6705809b..00000000
--- a/includes/messages/class-wp-notify-aggregate-message-factory.php
+++ /dev/null
@@ -1,16 +0,0 @@
-<?php
-
-final class WP_Notify_Aggregate_Message_Factory
-	extends WP_Notify_Aggregate_Factory
-	implements WP_Notify_Message_Factory {
-
-	/**
-	 * Get the interface that this aggregate factory can instantiate
-	 * implementations of.
-	 *
-	 * @return string Class name of the interface.
-	 */
-	protected function get_interface() {
-		return 'WP_Notify_Message_Factory';
-	}
-}
diff --git a/includes/messages/interface-wp-notify-message-factory.php b/includes/messages/interface-factory.php
similarity index 87%
rename from includes/messages/interface-wp-notify-message-factory.php
rename to includes/messages/interface-factory.php
index deb02d79..1e6aaa10 100644
--- a/includes/messages/interface-wp-notify-message-factory.php
+++ b/includes/messages/interface-factory.php
@@ -1,6 +1,8 @@
 <?php
 
-interface WP_Notify_Message_Factory {
+namespace WP\Notifications\Messages;
+
+interface Factory {
 
 	/**
 	 * Create a new instance of a notification message.
@@ -9,7 +11,7 @@ interface WP_Notify_Message_Factory {
 	 * @param string $type  Optional. Type of the message. Defaults to
 	 *                      'standard'.
 	 *
-	 * @return WP_Notify_Message
+	 * @return Message
 	 */
 	public function create( $value, $type = 'standard' );
 
diff --git a/includes/messages/interface-wp-notify-message.php b/includes/messages/interface-message.php
similarity index 69%
rename from includes/messages/interface-wp-notify-message.php
rename to includes/messages/interface-message.php
index f32a82ec..4e886032 100644
--- a/includes/messages/interface-wp-notify-message.php
+++ b/includes/messages/interface-message.php
@@ -1,8 +1,14 @@
 <?php
 
-interface WP_Notify_Message
+namespace WP\Notifications\Messages;
+
+use JsonSerializable;
+
+use WP\Notifications;
+
+interface Message
 	extends JsonSerializable,
-			WP_Notify_Json_Unserializable {
+	Notifications\Json_Unserializable {
 
 	/**
 	 * Get the message content.
diff --git a/includes/persistence/class-wp-notify-abstract-notification-repository.php b/includes/persistence/class-abstract-notification-repository.php
similarity index 66%
rename from includes/persistence/class-wp-notify-abstract-notification-repository.php
rename to includes/persistence/class-abstract-notification-repository.php
index 91ec59cb..cd66ec55 100644
--- a/includes/persistence/class-wp-notify-abstract-notification-repository.php
+++ b/includes/persistence/class-abstract-notification-repository.php
@@ -1,7 +1,13 @@
 <?php
 
-abstract class WP_Notify_Abstract_Notification_Repository
-	implements WP_Notify_Notification_Repository {
+namespace WP\Notifications\Persistence;
+
+use DateTime;
+use DateInterval;
+use WP\Notifications;
+
+abstract class Abstract_Notification_Repository
+	implements Notification_Repository {
 
 	/**
 	 * Find the latest notifications for a given date range.
@@ -12,8 +18,8 @@ abstract class WP_Notify_Abstract_Notification_Repository
 	 * @param int          $offset     Optional. Offset into the result set.
 	 *                                 Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array if
+	 *                                      none found.
 	 */
 	public function find_latest(
 		DateInterval $interval,
@@ -27,7 +33,7 @@ public function find_latest(
 		return $this->find_by_date_range(
 			$start,
 			$end,
-			WP_Notify_Order::DESCENDING,
+			Order::DESCENDING,
 			$pagination,
 			$offset
 		);
diff --git a/includes/persistence/class-wp-notify-wpdb-notification-repository.php b/includes/persistence/class-wpdb-notification-repository.php
similarity index 52%
rename from includes/persistence/class-wp-notify-wpdb-notification-repository.php
rename to includes/persistence/class-wpdb-notification-repository.php
index 5fd834ef..67ac44c4 100644
--- a/includes/persistence/class-wp-notify-wpdb-notification-repository.php
+++ b/includes/persistence/class-wpdb-notification-repository.php
@@ -1,15 +1,22 @@
 <?php
 
-class WP_Notify_Wpdb_Notification_Repository
-	extends WP_Notify_Abstract_Notification_Repository {
+namespace WP\Notifications\Persistence;
+
+use DateTimeInterface;
+
+use WP\Notifications;
+use WP\Notifications\Recipients;
+
+class Wpdb_Notification_Repository
+	extends Abstract_Notification_Repository {
 
 	/**
 	 * Find a notification by ID.
 	 *
 	 * @param int $id ID to look for.
 	 *
-	 * @return WP_Notify_Notification|false Notification that matches the ID, or
-	 *                                     false if not found.
+	 * @return Notifications\Notification|false Notification that matches the ID, or
+	 *                                          false if not found.
 	 */
 	public function find_by_id( $id ) {
 		if ( ! is_int( $id ) ) {
@@ -23,18 +30,18 @@ public function find_by_id( $id ) {
 	/**
 	 * Find all notifications for a given recipient.
 	 *
-	 * @param WP_Notify_Recipient $recipient  Recipient to retrieve the
-	 *                                       notifications for.
-	 * @param int                 $pagination Optional. Number of elements per
-	 *                                        page. Defaults to 10.
-	 * @param int                 $offset     Optional. Offset into the result
-	 *                                        set. Defaults to 0.
+	 * @param Recipients\Recipient $recipient  Recipient to retrieve the
+	 *                                         notifications for.
+	 * @param int                  $pagination Optional. Number of elements per
+	 *                                         page. Defaults to 10.
+	 * @param int                  $offset     Optional. Offset into the result
+	 *                                         set. Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array if
+	 *                                      none found.
 	 */
 	public function find_by_recipient(
-		WP_Notify_Recipient $recipient,
+		Recipients\Recipient $recipient,
 		$pagination = 10,
 		$offset = 0
 	) {
@@ -47,21 +54,20 @@ public function find_by_recipient(
 	 *
 	 * @param DateTimeInterface $start      Start date of the date range.search.
 	 * @param DateTimeInterface $end        End date of the date range.search.
-	 * @param string            $order      Optional. Sorting order, defaults
-	 *                                      to
+	 * @param string            $order      Optional. Sorting order, defaults to
 	 *                                      descending.
 	 * @param int               $pagination Optional. Number of elements per
 	 *                                      page. Defaults to 10.
 	 * @param int               $offset     Optional. Offset into the result
 	 *                                      set. Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array if
+	 *                                      none found.
 	 */
 	public function find_by_date_range(
 		DateTimeInterface $start,
 		DateTimeInterface $end,
-		$order = WP_Notify_Order::DESCENDING,
+		$order = Order::DESCENDING,
 		$pagination = 10,
 		$offset = 0
 	) {
@@ -72,11 +78,11 @@ public function find_by_date_range(
 	/**
 	 * Add a new notification to the repository.
 	 *
-	 * @param WP_Notify_Notification $notification Notification to add.
+	 * @param Notifications\Notification $notification Notification to add.
 	 *
 	 * @return int ID that the notification was stored under.
 	 */
-	public function add( WP_Notify_Notification $notification ) {
+	public function add( Notifications\Notification $notification ) {
 		// TODO: Implement query.
 		return -1;
 	}
diff --git a/includes/persistence/interface-wp-notify-notification-repository.php b/includes/persistence/interface-notification-repository.php
similarity index 55%
rename from includes/persistence/interface-wp-notify-notification-repository.php
rename to includes/persistence/interface-notification-repository.php
index 72053a87..5188e225 100644
--- a/includes/persistence/interface-wp-notify-notification-repository.php
+++ b/includes/persistence/interface-notification-repository.php
@@ -1,32 +1,41 @@
 <?php
 
-interface WP_Notify_Notification_Repository {
+namespace WP\Notifications\Persistence;
+
+use DateInterval;
+use DateTimeInterface;
+
+use WP\Notifications;
+use WP\Notifications\Recipients;
+
+
+interface Notification_Repository {
 
 	/**
 	 * Find a notification by ID.
 	 *
 	 * @param int $id ID to look for.
 	 *
-	 * @return WP_Notify_Notification|false Notification that matches the ID, or
-	 *                                     false if not found.
+	 * @return Notifications\Notification|false Notification that matches the ID, or
+	 *                                          false if not found.
 	 */
 	public function find_by_id( $id );
 
 	/**
 	 * Find all notifications for a given recipient.
 	 *
-	 * @param WP_Notify_Recipient $recipient  Recipient to retrieve the
-	 *                                       notifications for.
-	 * @param int                 $pagination Optional. Number of elements per
-	 *                                        page. Defaults to 10.
-	 * @param int                 $offset     Optional. Offset into the result
-	 *                                        set. Defaults to 0.
+	 * @param Recipients\Recipient $recipient  Recipient to retrieve the
+	 *                                         notifications for.
+	 * @param int                  $pagination Optional. Number of elements per
+	 *                                         page. Defaults to 10.
+	 * @param int                  $offset     Optional. Offset into the result
+	 *                                         set. Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array if
+	 *                                      none found.
 	 */
 	public function find_by_recipient(
-		WP_Notify_Recipient $recipient,
+		Recipients\Recipient $recipient,
 		$pagination = 10,
 		$offset = 0
 	);
@@ -44,13 +53,13 @@ public function find_by_recipient(
 	 * @param int               $offset     Optional. Offset into the result
 	 *                                      set. Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array if
+	 *                                      none found.
 	 */
 	public function find_by_date_range(
 		DateTimeInterface $start,
 		DateTimeInterface $end,
-		$order = WP_Notify_Order::DESCENDING,
+		$order = Order::DESCENDING,
 		$pagination = 10,
 		$offset = 0
 	);
@@ -64,8 +73,8 @@ public function find_by_date_range(
 	 * @param int          $offset     Optional. Offset into the result set.
 	 *                                 Defaults to 0.
 	 *
-	 * @return WP_Notify_Notification[] Array of notifications, empty array if
-	 *                                 none found.
+	 * @return Notifications\Notification[] Array of notifications, empty array
+	 *                                      if none found.
 	 */
 	public function find_latest(
 		DateInterval $interval,
@@ -76,9 +85,9 @@ public function find_latest(
 	/**
 	 * Add a new notification to the repository.
 	 *
-	 * @param WP_Notify_Notification $notification Notification to add.
+	 * @param Notifications\Notification $notification Notification to add.
 	 *
 	 * @return int ID that the notification was stored under.
 	 */
-	public function add( WP_Notify_Notification $notification );
+	public function add( Notifications\Notification $notification );
 }
diff --git a/includes/persistence/interface-wp-notify-order.php b/includes/persistence/interface-order.php
similarity index 52%
rename from includes/persistence/interface-wp-notify-order.php
rename to includes/persistence/interface-order.php
index ca70fb8f..3d5fee9f 100644
--- a/includes/persistence/interface-wp-notify-order.php
+++ b/includes/persistence/interface-order.php
@@ -1,6 +1,8 @@
 <?php
 
-interface WP_Notify_Order {
+namespace WP\Notifications\Persistence;
+
+interface Order {
 
 	const ASCENDING  = 'asc';
 	const DESCENDING = 'desc';
diff --git a/includes/recipients/class-aggregate-factory.php b/includes/recipients/class-aggregate-factory.php
new file mode 100644
index 00000000..33dd1733
--- /dev/null
+++ b/includes/recipients/class-aggregate-factory.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace WP\Notifications\Recipients;
+
+use WP\Notifications;
+
+final class Aggregate_Factory
+	extends Notifications\Aggregate_Factory
+	implements Factory {
+
+	/**
+	 * Get the interface that this aggregate factory can instantiate
+	 * implementations of.
+	 *
+	 * @return string Class name of the interface.
+	 */
+	protected function get_interface() {
+		return 'WP\Notifications\Recipients\Factory';
+	}
+}
diff --git a/includes/recipients/class-wp-notify-base-recipient-factory.php b/includes/recipients/class-base-factory.php
similarity index 75%
rename from includes/recipients/class-wp-notify-base-recipient-factory.php
rename to includes/recipients/class-base-factory.php
index 26494c4b..ba987a0f 100644
--- a/includes/recipients/class-wp-notify-base-recipient-factory.php
+++ b/includes/recipients/class-base-factory.php
@@ -1,6 +1,10 @@
 <?php
 
-final class WP_Notify_Base_Recipient_Factory implements WP_Notify_Recipient_Factory {
+namespace WP\Notifications\Recipients;
+
+use WP\Notifications\Exceptions;
+
+final class Base_Factory implements Factory {
 
 	const TYPE_USER = 'user';
 	const TYPE_ROLE = 'role';
@@ -11,13 +15,12 @@ final class WP_Notify_Base_Recipient_Factory implements WP_Notify_Recipient_Fact
 	 * @param mixed  $value Value of the recipient.
 	 * @param string $type  Optional. Type of the recipient. Defaults to 'user'.
 	 *
-	 * @return WP_Notify_Recipient
-	 *
-	 * @throws WP_Notify_Invalid_Type If the recipient type was not valid.
+	 * @return Recipient The created recipient instance.
+	 * @throws Exceptions\Invalid_Type If the recipient type was not valid.
 	 */
 	public function create( $value, $type = self::TYPE_USER ) {
 		if ( ! $this->accepts( $type ) ) {
-			throw WP_Notify_Invalid_Type::from_recipient_type( $type );
+			throw Exceptions\Invalid_Type::from_recipient_type( $type );
 		}
 
 		list( $type, $value ) = $this->validate( $type, $value );
@@ -44,11 +47,11 @@ public function accepts( $type ) {
 	 * @param string $type Type to get the implementation class for.
 	 *
 	 * @return string Implementation class.
-	 * @throws WP_Notify_Invalid_Type If the recipient type was not valid.
+	 * @throws Exceptions\Invalid_Type If the recipient type was not valid.
 	 */
 	public function get_implementation_for_type( $type ) {
 		if ( ! $this->accepts( $type ) ) {
-			throw WP_Notify_Invalid_Type::from_recipient_type( $type );
+			throw Exceptions\Invalid_Type::from_recipient_type( $type );
 		}
 
 		$mappings = $this->get_type_mappings();
@@ -77,10 +80,10 @@ private function validate( $type, $value ) {
 	 */
 	private function get_type_mappings() {
 		return apply_filters(
-			'wp_notify_recipient_type_mappings',
+			'wp_feature_notifications_recipient_type_mappings',
 			array(
-				self::TYPE_USER => 'WP_Notify_User_Recipient',
-				self::TYPE_ROLE => 'WP_Notify_Role_Recipient',
+				self::TYPE_USER => 'User_Recipient',
+				self::TYPE_ROLE => 'Role_Recipient',
 			)
 		);
 	}
diff --git a/includes/recipients/class-wp-notify-recipient-collection.php b/includes/recipients/class-collection.php
similarity index 75%
rename from includes/recipients/class-wp-notify-recipient-collection.php
rename to includes/recipients/class-collection.php
index 011d403f..d5ef6c4b 100644
--- a/includes/recipients/class-wp-notify-recipient-collection.php
+++ b/includes/recipients/class-collection.php
@@ -1,20 +1,29 @@
 <?php
 
-class WP_Notify_Recipient_Collection
+namespace WP\Notifications\Recipients;
+
+use Iterator;
+use Countable;
+use JsonSerializable;
+
+use WP\Notifications;
+use WP\Notifications\Exceptions;
+
+class Collection
 	implements Iterator,
 		Countable,
 		JsonSerializable,
-		WP_Notify_Json_Unserializable {
+		Notifications\Json_Unserializable {
 
 	/**
 	 * Internal array of recipients.
 	 *
-	 * @var WP_Notify_Recipient[]
+	 * @var Recipient[]
 	 */
 	protected $recipients = array();
 
 	/**
-	 * Instantiates a WPNotify_RecipientCollection object.
+	 * Instantiates a Collection object.
 	 *
 	 * @param array $recipients Array of recipients to instantiate the
 	 *                          collection with.
@@ -26,13 +35,11 @@ public function __construct( $recipients = array() ) {
 	/**
 	 * Validate the recipients.
 	 *
-	 * @param WP_Notify_Recipient|array $recipients Recipient or array of
-	 *                                                    recipients to
-	 *                                                    validate.
+	 * @param Recipient|array $recipients Recipient or array of
+	 *                                    recipients to validate.
 	 *
 	 * @return array Validated array of recipients.
-	 *
-	 * @throws WP_Notify_Failed_To_Add_Recipient If a recipient could not be added.
+	 * @throws Failed_To_Add_Recipient If a recipient could not be added.
 	 */
 	protected function validate_recipients( $recipients ) {
 		if ( ! is_array( $recipients ) ) {
@@ -40,26 +47,26 @@ protected function validate_recipients( $recipients ) {
 		}
 
 		foreach ( $recipients as $recipient ) {
-			if ( ! $recipient instanceof WP_Notify_Recipient ) {
-				throw WP_Notify_Failed_To_Add_Recipient::from_invalid_recipient( $recipient );
+			if ( ! $recipient instanceof Recipient ) {
+				throw Exceptions\Failed_To_Add_Recipient::from_invalid_recipient( $recipient );
 			}
 		}
 
 		return $recipients;
 	}
 
-	public function add( WP_Notify_Recipient $recipient ) {
+	public function add( Recipient $recipient ) {
 		$this->recipients[] = $recipient;
 	}
 
-	public function count() {
+	public function count(): int {
 		return count( $this->recipients );
 	}
 
 	/**
 	 * Return the current recipient.
 	 *
-	 * @return WP_Notify_Recipient Recipient
+	 * @return Recipient Recipient
 	 */
 	public function current() {
 		return current( $this->recipients );
diff --git a/includes/recipients/class-wp-notify-role-recipient.php b/includes/recipients/class-role.php
similarity index 65%
rename from includes/recipients/class-wp-notify-role-recipient.php
rename to includes/recipients/class-role.php
index bb6a639e..78273cd3 100644
--- a/includes/recipients/class-wp-notify-role-recipient.php
+++ b/includes/recipients/class-role.php
@@ -1,6 +1,8 @@
 <?php
 
-final class WP_Notify_Role_Recipient implements WP_Notify_Recipient {
+namespace WP\Notifications\Recipients;
+
+final class Role implements Recipient {
 
 	private $role;
 
diff --git a/includes/recipients/class-wp-notify-user-recipient.php b/includes/recipients/class-user.php
similarity index 71%
rename from includes/recipients/class-wp-notify-user-recipient.php
rename to includes/recipients/class-user.php
index 94f73598..41c31c78 100644
--- a/includes/recipients/class-wp-notify-user-recipient.php
+++ b/includes/recipients/class-user.php
@@ -1,6 +1,12 @@
 <?php
 
-final class WP_Notify_User_Recipient implements WP_Notify_Recipient {
+namespace WP\Notifications\Recipients;
+
+use WP_User;
+
+use WP\Notifications\Exceptions\Invalid_Recipient;
+
+final class User implements Recipient {
 
 	private $user_id;
 	private $user_object;
@@ -24,7 +30,7 @@ public function get_user_object() {
 	private function validate( $user_id ) {
 		if ( ! is_numeric( $user_id )
 			|| ! ( ( (int) $user_id ) > 0 ) ) {
-			throw WP_Notify_Invalid_Recipient::from_invalid_user_id( $user_id );
+			throw Invalid_Recipient::from_invalid_user_id( $user_id );
 		}
 
 		return $user_id;
diff --git a/includes/recipients/interface-wp-notify-recipient-factory.php b/includes/recipients/interface-factory.php
similarity index 85%
rename from includes/recipients/interface-wp-notify-recipient-factory.php
rename to includes/recipients/interface-factory.php
index 348d58d5..378e1f8d 100644
--- a/includes/recipients/interface-wp-notify-recipient-factory.php
+++ b/includes/recipients/interface-factory.php
@@ -1,6 +1,8 @@
 <?php
 
-interface WP_Notify_Recipient_Factory {
+namespace WP\Notifications\Recipients;
+
+interface Factory {
 
 	/**
 	 * Create a new instance of a notification recipient.
@@ -8,7 +10,7 @@ interface WP_Notify_Recipient_Factory {
 	 * @param mixed  $value Value of the recipient.
 	 * @param string $type  Optional. Type of the recipient. Defaults to 'user'.
 	 *
-	 * @return WP_Notify_Recipient
+	 * @return Recipient
 	 */
 	public function create( $value, $type = 'user' );
 
diff --git a/includes/recipients/interface-recipient.php b/includes/recipients/interface-recipient.php
new file mode 100644
index 00000000..529c8633
--- /dev/null
+++ b/includes/recipients/interface-recipient.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace WP\Notifications\Recipients;
+
+interface Recipient {
+
+}
diff --git a/includes/recipients/interface-wp-notify-recipient.php b/includes/recipients/interface-wp-notify-recipient.php
deleted file mode 100644
index 5188e0af..00000000
--- a/includes/recipients/interface-wp-notify-recipient.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-interface WP_Notify_Recipient {
-
-}
diff --git a/includes/senders/class-wp-notify-base-sender.php b/includes/senders/class-base-sender.php
similarity index 76%
rename from includes/senders/class-wp-notify-base-sender.php
rename to includes/senders/class-base-sender.php
index 0b0c5a9c..a650cc13 100644
--- a/includes/senders/class-wp-notify-base-sender.php
+++ b/includes/senders/class-base-sender.php
@@ -1,6 +1,12 @@
 <?php
 
-class WP_Notify_Base_Sender implements WP_Notify_Sender, WP_Notify_Json_Unserializable {
+namespace WP\Notifications\Senders;
+
+use WP\Notifications;
+
+use ReflectionClass;
+
+class Base_Sender implements Sender, Notifications\Json_Unserializable {
 
 	/**
 	 * @var string
@@ -8,15 +14,15 @@ class WP_Notify_Base_Sender implements WP_Notify_Sender, WP_Notify_Json_Unserial
 	protected $name;
 
 	/**
-	 * @var WP_Notify_Base_Image
+	 * @var Base_Image
 	 */
 	protected $image;
 
 	/**
-	 * WPNotify_BaseSender constructor.
+	 * BaseSender constructor.
 	 *
-	 * @param string                    $name
-	 * @param WP_Notify_Base_Image|null $image
+	 * @param string          $name
+	 * @param Base_Image|null $image
 	 */
 	public function __construct( $name, $image = null ) {
 		$this->name  = $name;
@@ -59,7 +65,7 @@ public static function json_unserialize( $json ) {
 
 		$image = null;
 
-		if ( ! empty( $image_data ) && is_subclass_of( $class_name, 'WP_Notify_Image' ) ) {
+		if ( ! empty( $image_data ) && is_subclass_of( $class_name, 'Image' ) ) {
 			$image_reflection = new ReflectionClass( $class_name );
 			$image            = $image_reflection->newInstanceArgs( array_values( $image_data ) );
 		}
@@ -78,7 +84,7 @@ public function get_name() {
 	}
 
 	/**
-	 * @return WP_Notify_Base_Image|null
+	 * @return Base_Image|null
 	 */
 	public function get_image() {
 		return $this->image;
diff --git a/includes/senders/interface-wp-notify-sender-factory.php b/includes/senders/interface-factory.php
similarity index 63%
rename from includes/senders/interface-wp-notify-sender-factory.php
rename to includes/senders/interface-factory.php
index eeaa2a13..8391844b 100644
--- a/includes/senders/interface-wp-notify-sender-factory.php
+++ b/includes/senders/interface-factory.php
@@ -1,13 +1,15 @@
 <?php
 
-interface WP_Notify_Sender_Factory {
+namespace WP\Notifications\Senders;
+
+interface Factory {
 
 	/**
 	 * Create a new instance of notification sender
 	 *
 	 * @param string $name
 	 *
-	 * @return WP_Notify_Sender
+	 * @return Sender
 	 */
 	public function create( $name );
 }
diff --git a/includes/senders/interface-sender.php b/includes/senders/interface-sender.php
new file mode 100644
index 00000000..60522dc6
--- /dev/null
+++ b/includes/senders/interface-sender.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace WP\Notifications\Senders;
+
+use JsonSerializable;
+
+interface Sender extends JsonSerializable {
+
+}
diff --git a/includes/senders/interface-wp-notify-sender.php b/includes/senders/interface-wp-notify-sender.php
deleted file mode 100644
index ef0fbab3..00000000
--- a/includes/senders/interface-wp-notify-sender.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-interface WP_Notify_Sender extends JsonSerializable {
-
-}
diff --git a/tests/phpunit/includes/bootstrap.php b/tests/phpunit/includes/bootstrap.php
index 7aa3af6b..c0249c57 100644
--- a/tests/phpunit/includes/bootstrap.php
+++ b/tests/phpunit/includes/bootstrap.php
@@ -39,4 +39,4 @@ function handle_wp_setup_failure( $message ) {
 remove_filter( 'wp_die_handler', 'handle_wp_setup_failure' );
 
 require dirname( __FILE__ ) . '/class-dummy-message.php';
-require dirname( __FILE__ ) . '/class-wp-notify-test-case.php';
+require dirname( __FILE__ ) . '/class-test-case.php';
diff --git a/tests/phpunit/includes/class-dummy-message.php b/tests/phpunit/includes/class-dummy-message.php
index ee9eb53f..ac719d90 100644
--- a/tests/phpunit/includes/class-dummy-message.php
+++ b/tests/phpunit/includes/class-dummy-message.php
@@ -1,6 +1,10 @@
 <?php
 
-class Dummy_Message implements WP_Notify_Message {
+namespace WP\Notifications\Tests;
+
+use WP\Notifications\Messages;
+
+class Dummy_Message implements Messages\Message {
 
 	public function serialize() {
 		return ''; }
diff --git a/tests/phpunit/includes/class-test-case.php b/tests/phpunit/includes/class-test-case.php
new file mode 100644
index 00000000..1082b57b
--- /dev/null
+++ b/tests/phpunit/includes/class-test-case.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+class TestCase extends \PHPUnit\Framework\TestCase {
+
+}
diff --git a/tests/phpunit/includes/class-wp-notify-test-case.php b/tests/phpunit/includes/class-wp-notify-test-case.php
deleted file mode 100644
index 9edce3d6..00000000
--- a/tests/phpunit/includes/class-wp-notify-test-case.php
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-use PHPUnit\Framework\TestCase;
-
-class WP_Notify_TestCase extends TestCase {
-
-}
diff --git a/tests/phpunit/tests/test-wp-notify-base-image.php b/tests/phpunit/tests/test-base-image.php
similarity index 85%
rename from tests/phpunit/tests/test-wp-notify-base-image.php
rename to tests/phpunit/tests/test-base-image.php
index 62c34e18..8422f283 100644
--- a/tests/phpunit/tests/test-wp-notify-base-image.php
+++ b/tests/phpunit/tests/test-base-image.php
@@ -1,6 +1,10 @@
 <?php
 
-class Test_WP_Notify_BaseImage extends WP_Notify_TestCase {
+namespace WP\Notifications\Tests;
+
+use WP\Notifications\Image;
+
+class Test_BaseImage extends TestCase {
 
 	/**
 	 * @param array  $image_data
@@ -13,7 +17,7 @@ public function test_it_can_be_json_encoded( $image_data, $expected_json ) {
 		$source = $image_data['source'];
 		$alt    = $image_data['alt'];
 
-		$image_instance = new WP_Notify_Base_Image( $source, $alt );
+		$image_instance = new Image\Base_Image( $source, $alt );
 		$encoded_image  = json_encode( $image_instance );
 
 		$this->assertEquals( $expected_json, $encoded_image );
@@ -29,11 +33,11 @@ public function test_it_can_be_json_encoded( $image_data, $expected_json ) {
 	 */
 	public function test_it_can_be_instantiated_from_json( $image_data, $json ) {
 
-		$test_instance = WP_Notify_Base_Image::json_unserialize( $json );
+		$test_instance = Image\Base_Image::json_unserialize( $json );
 
 		list( $source, $alt ) = array_values( $image_data );
 
-		$instance = new WP_Notify_Base_Image( $source, $alt );
+		$instance = new Image\Base_Image( $source, $alt );
 
 		$this->assertEquals( $instance->get_source(), $test_instance->get_source() );
 		$this->assertEquals( $instance->get_alt(), $test_instance->get_alt() );
diff --git a/tests/phpunit/tests/test-base-message.php b/tests/phpunit/tests/test-base-message.php
new file mode 100644
index 00000000..6811b5fc
--- /dev/null
+++ b/tests/phpunit/tests/test-base-message.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+use WP\Notifications\Messages;
+
+class Test_Base_Message extends TestCase {
+
+	public function test_it_can_be_instantiated() {
+		$testee = new Messages\Base_Message( 'Message' );
+		$this->assertInstanceOf( '\WP\Notifications\Messages\Base_Message', $testee );
+	}
+
+	public function test_it_implements_the_interface() {
+		$testee = new Messages\Base_Message( 'Message' );
+		$this->assertInstanceOf( '\WP\Notifications\Messages\Message', $testee );
+	}
+
+	public function test_it_can_return_its_content() {
+		$testee = new Messages\Base_Message( 'Message' );
+		$this->assertEquals( 'Message', $testee->get_content() );
+	}
+
+	public function test_it_can_be_cast_to_string() {
+		$testee = new Messages\Base_Message( 'Message' );
+		$this->assertEquals( 'Message', (string) $testee );
+	}
+}
diff --git a/tests/phpunit/tests/test-base-notification.php b/tests/phpunit/tests/test-base-notification.php
new file mode 100644
index 00000000..cb509f1c
--- /dev/null
+++ b/tests/phpunit/tests/test-base-notification.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+use WP\Notifications;
+
+class Test_Base_Notification extends TestCase {
+
+	public function test_it_can_be_instantiated() {
+		$sender_mock     = $this->createMock( '\WP\Notifications\Senders\Base_Sender' );
+		$recipients_mock = $this->createMock( '\WP\Notifications\Recipients\Collection' );
+		$testee          = new Notifications\Base_Notification(
+			$sender_mock,
+			$recipients_mock,
+			new Dummy_Message()
+		);
+		$this->assertInstanceOf( '\WP\Notifications\Base_Notification', $testee );
+	}
+
+	public function test_it_implements_the_interface() {
+		$sender_mock     = $this->createMock( '\WP\Notifications\Senders\Base_Sender' );
+		$recipients_mock = $this->createMock( '\WP\Notifications\Recipients\Collection' );
+		$testee          = new Notifications\Base_Notification(
+			$sender_mock,
+			$recipients_mock,
+			new Dummy_Message()
+		);
+		$this->assertInstanceOf( '\WP\Notifications\Notification', $testee );
+	}
+
+	public function test_it_can_return_its_content() {
+		$sender_mock     = $this->createMock( '\WP\Notifications\Senders\Base_Sender' );
+		$recipients_mock = $this->createMock( '\WP\Notifications\Recipients\Collection' );
+		$dummy_message   = new Dummy_Message();
+		$testee          = new Notifications\Base_Notification(
+			$sender_mock,
+			$recipients_mock,
+			$dummy_message
+		);
+		$this->assertEquals( $recipients_mock, $testee->get_recipients() );
+		$this->assertEquals( $dummy_message, $testee->get_message() );
+	}
+}
diff --git a/tests/phpunit/tests/test-wp-notify-factory.php b/tests/phpunit/tests/test-factory.php
similarity index 53%
rename from tests/phpunit/tests/test-wp-notify-factory.php
rename to tests/phpunit/tests/test-factory.php
index 763c734b..61caaf75 100644
--- a/tests/phpunit/tests/test-wp-notify-factory.php
+++ b/tests/phpunit/tests/test-factory.php
@@ -1,28 +1,31 @@
 <?php
 
-class Test_WP_Notify_Factory extends WP_Notify_TestCase {
+namespace WP\Notifications\Tests;
 
+use WP\Notifications;
+
+class Test_Factory extends TestCase {
 
 	public function test_create_with_vendor_sender() {
 
-		$vendor_sender = $this->createMock( 'WP_Notify_Sender' );
+		$vendor_sender = $this->createMock( '\WP\Notifications\Senders\Sender' );
 
-		$message_factory = $this->getMockBuilder( 'WP_Notify_Message_Factory' )
+		$message_factory = $this->getMockBuilder( '\WP\Notifications\Messages\Factory' )
 								->setMethods( array( 'create', 'accepts' ) )
 								->getMock();
 
-		$message_factory->method( 'create' )->willReturn( $this->createMock( 'WP_Notify_Message' ) );
+		$message_factory->method( 'create' )->willReturn( $this->createMock( '\WP\Notifications\Messages\Message' ) );
 		$message_factory->method( 'accepts' )->willReturn( true );
 
-		$sender_factory = $this->getMockBuilder( 'WP_Notify_Sender_Factory' )
+		$sender_factory = $this->getMockBuilder( '\WP\Notifications\Senders\Factory' )
 			->setMethods( array( 'create' ) )
 			->getMock();
 
-		$sender_factory->method( 'create' )->willReturn( $this->createMock( 'WP_Notify_Sender' ) );
+		$sender_factory->method( 'create' )->willReturn( $this->createMock( '\WP\Notifications\Senders\Sender' ) );
 
-		$factory = new WP_Notify_Factory(
+		$factory = new Notifications\Factory(
 			$message_factory,
-			$this->createMock( 'WP_Notify_Recipient_Factory' ),
+			$this->createMock( '\WP\Notifications\Recipients\Factory' ),
 			$sender_factory
 		);
 
diff --git a/tests/phpunit/tests/test-wp-notify-notification-repository.php b/tests/phpunit/tests/test-notification-repository.php
similarity index 66%
rename from tests/phpunit/tests/test-wp-notify-notification-repository.php
rename to tests/phpunit/tests/test-notification-repository.php
index d112b755..19dc9e89 100644
--- a/tests/phpunit/tests/test-wp-notify-notification-repository.php
+++ b/tests/phpunit/tests/test-notification-repository.php
@@ -1,10 +1,16 @@
 <?php
 
-class Test_WP_Notify_Wpdb_Notification_Repository extends WP_Notify_TestCase {
+namespace WP\Notifications\Tests;
+
+use stdClass;
+
+use WP\Notifications\Persistence;
+
+class Test_Wpdb_Notification_Repository extends TestCase {
 
 	/** @dataProvider data_provider_it_returns_false_on_invalid_ids */
 	public function test_it_returns_false_on_invalid_ids( $id ) {
-		$testee = new WP_Notify_Wpdb_Notification_Repository();
+		$testee = new Persistence\Wpdb_Notification_Repository();
 		$result = $testee->find_by_id( $id );
 		$this->assertFalse( $result );
 	}
diff --git a/tests/phpunit/tests/test-recipient-collection.php b/tests/phpunit/tests/test-recipient-collection.php
new file mode 100644
index 00000000..a28423b4
--- /dev/null
+++ b/tests/phpunit/tests/test-recipient-collection.php
@@ -0,0 +1,97 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+use stdClass;
+
+use WP\Notifications\Recipients;
+
+class Test_Recipient_Collection extends TestCase {
+
+	public function test_it_can_be_instantiated() {
+		$testee = new Recipients\Collection();
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Collection', $testee );
+	}
+
+	public function test_it_is_countable() {
+		$testee = new Recipients\Collection();
+		$this->assertInstanceOf( 'Countable', $testee );
+	}
+
+	public function test_it_is_traversable() {
+		$testee = new Recipients\Collection();
+		$this->assertInstanceOf( 'Traversable', $testee );
+	}
+
+	public function test_it_is_empty_when_instantiated_without_arguments() {
+		$testee = new Recipients\Collection();
+		$this->assertCount( 0, $testee );
+	}
+
+	public function test_it_can_accept_a_singular_recipient() {
+		$mock_recipient = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$testee         = new Recipients\Collection( $mock_recipient );
+		$this->assertCount( 1, $testee );
+	}
+
+	public function test_it_can_accept_an_array_of_recipients() {
+		$mock_recipient_1 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$mock_recipient_2 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$mock_recipient_3 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$testee           = new Recipients\Collection(
+			array(
+				$mock_recipient_1,
+				$mock_recipient_2,
+				$mock_recipient_3,
+			)
+		);
+		$this->assertCount( 3, $testee );
+	}
+
+	public function test_recipients_can_be_added() {
+		$mock_recipient_1 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$mock_recipient_2 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$mock_recipient_3 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$testee           = new Recipients\Collection( $mock_recipient_1 );
+		$this->assertCount( 1, $testee );
+		$testee->add( $mock_recipient_2 );
+		$this->assertCount( 2, $testee );
+		$testee->add( $mock_recipient_3 );
+		$this->assertCount( 3, $testee );
+	}
+
+	/** @dataProvider data_provider_it_throws_on_invalid_type */
+	public function test_it_throws_on_invalid_type( $invalid_recipient ) {
+		$this->expectException( '\WP\Notifications\Exceptions\Runtime_Exception' );
+		new Recipients\Collection( $invalid_recipient );
+	}
+
+	public function data_provider_it_throws_on_invalid_type() {
+		$mock_recipient_1 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+		$mock_recipient_2 = $this->createMock( '\WP\Notifications\Recipients\Recipient' );
+
+		return array(
+			array( null ),
+			array( true ),
+			array( new stdClass ),
+			array( 'invalid' ),
+			array( array( 1, 2, 3 ) ),
+			array( array( $mock_recipient_1, 'invalid', $mock_recipient_2 ) ),
+		);
+	}
+
+	public function test_it_can_be_json_encoded() {
+		$testee = new Recipients\Collection( array() );
+		$this->assertEquals(
+			'[]',
+			json_encode( $testee )
+		);
+	}
+
+	public function test_it_can_be_instantiated_from_json() {
+		$json   = '[]';
+		$testee = Recipients\Collection::json_unserialize( $json );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Collection', $testee );
+		$this->assertEquals( 0, $testee->count() );
+	}
+}
diff --git a/tests/phpunit/tests/test-role-recipient.php b/tests/phpunit/tests/test-role-recipient.php
new file mode 100644
index 00000000..d92a6092
--- /dev/null
+++ b/tests/phpunit/tests/test-role-recipient.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+use WP\Notifications\Recipients;
+
+class Test_Role_Recipient extends TestCase {
+
+	public function test_it_can_be_instantiated() {
+		$testee = new Recipients\Role( 1 );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Role', $testee );
+	}
+
+	public function test_it_implements_the_interface() {
+		$testee = new Recipients\Role( 1 );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Recipient', $testee );
+	}
+}
diff --git a/tests/phpunit/tests/test-user-recipient.php b/tests/phpunit/tests/test-user-recipient.php
new file mode 100644
index 00000000..60ed2d72
--- /dev/null
+++ b/tests/phpunit/tests/test-user-recipient.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace WP\Notifications\Tests;
+
+use stdClass;
+
+use WP\Notifications\Recipients;
+
+class Test_User_Recipient extends TestCase {
+
+	public function test_it_can_be_instantiated() {
+		$testee = new Recipients\User( 1 );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\User', $testee );
+	}
+
+	public function test_it_implements_the_recipient_interface() {
+		$testee = new Recipients\User( 1 );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Recipient', $testee );
+	}
+
+	public function test_it_accepts_a_user_id_as_a_string() {
+		$testee = new Recipients\User( '1' );
+		$this->assertInstanceOf( '\WP\Notifications\Recipients\Recipient', $testee );
+	}
+
+	/** @dataProvider data_provider_it_throws_on_invalid_type */
+	public function test_it_throws_on_invalid_type( $invalid_user_id ) {
+		$this->expectException( '\WP\Notifications\Exceptions\Invalid_Recipient' );
+		new Recipients\User( $invalid_user_id );
+	}
+
+	public function data_provider_it_throws_on_invalid_type() {
+		return array(
+			array( null ),
+			array( - 1 ),
+			array( 0 ),
+			array( 'invalid' ),
+			array( new stdClass ),
+			array( array( 1, 2 ) ),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/test-wp-notify-base-message.php b/tests/phpunit/tests/test-wp-notify-base-message.php
deleted file mode 100644
index 025f759a..00000000
--- a/tests/phpunit/tests/test-wp-notify-base-message.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php
-
-class Test_WP_Notify_Base_Message extends WP_Notify_TestCase {
-
-	const SERIALIZED = 'C:20:"WPNotify_BaseMessage":14:{s:7:"Message";}';
-
-	public function test_it_can_be_instantiated() {
-		$testee = new WP_Notify_Base_Message( 'Message' );
-		$this->assertInstanceOf( 'WP_Notify_Base_Message', $testee );
-	}
-
-	public function test_it_implements_the_interface() {
-		$testee = new WP_Notify_Base_Message( 'Message' );
-		$this->assertInstanceOf( 'WP_Notify_Message', $testee );
-	}
-
-	public function test_it_can_return_its_content() {
-		$testee = new WP_Notify_Base_Message( 'Message' );
-		$this->assertEquals( 'Message', $testee->get_content() );
-	}
-
-	public function test_it_can_be_cast_to_string() {
-		$testee = new WP_Notify_Base_Message( 'Message' );
-		$this->assertEquals( 'Message', (string) $testee );
-	}
-
-	public function test_it_can_be_json_encoded() {
-		$testee = new WP_Notify_Base_Message( 'Message' );
-		$this->assertEquals(
-			'"Message"',
-			json_encode( $testee )
-		);
-	}
-
-	public function test_it_can_be_instantiated_from_json() {
-		$json   = '"Message"';
-		$testee = WP_Notify_Base_Message::json_unserialize( $json );
-		$this->assertInstanceOf( 'WP_Notify_Base_Message', $testee );
-		$this->assertEquals( 'Message', $testee->get_content() );
-	}
-}
diff --git a/tests/phpunit/tests/test-wp-notify-base-notification.php b/tests/phpunit/tests/test-wp-notify-base-notification.php
deleted file mode 100644
index f442622a..00000000
--- a/tests/phpunit/tests/test-wp-notify-base-notification.php
+++ /dev/null
@@ -1,73 +0,0 @@
-<?php
-
-class Test_WP_Notify_Base_Notification extends WP_Notify_TestCase {
-
-	const JSON_SERIALIZED = '{"WP_Notify_Recipient_Collection":[],"WP_Notify_Base_Message":"Message","WP_Notify_Base_Sender":{"name":"Name 1"}}';
-
-	public function test_it_can_be_instantiated() {
-		$sender_mock     = $this->createMock( 'WP_Notify_Base_Sender' );
-		$recipients_mock = $this->createMock( 'WP_Notify_Recipient_Collection' );
-		$testee          = new WP_Notify_Base_Notification(
-			$sender_mock,
-			$recipients_mock,
-			new Dummy_Message()
-		);
-		$this->assertInstanceOf( 'WP_Notify_Base_Notification', $testee );
-	}
-
-	public function test_it_implements_the_interface() {
-		$sender_mock     = $this->createMock( 'WP_Notify_Base_Sender' );
-		$recipients_mock = $this->createMock( 'WP_Notify_Recipient_Collection' );
-		$testee          = new WP_Notify_Base_Notification(
-			$sender_mock,
-			$recipients_mock,
-			new Dummy_Message()
-		);
-		$this->assertInstanceOf( 'WP_Notify_Notification', $testee );
-	}
-
-	public function test_it_can_return_its_content() {
-		$sender_mock     = $this->createMock( 'WP_Notify_Base_Sender' );
-		$recipients_mock = $this->createMock( 'WP_Notify_Recipient_Collection' );
-		$dummy_message   = new Dummy_Message();
-		$testee          = new WP_Notify_Base_Notification(
-			$sender_mock,
-			$recipients_mock,
-			$dummy_message
-		);
-		$this->assertEquals( $recipients_mock, $testee->get_recipients() );
-		$this->assertEquals( $dummy_message, $testee->get_message() );
-	}
-
-	public function test_it_can_be_json_encoded() {
-		$sender_mock      = new WP_Notify_Base_Sender( 'Name 1' );
-		$empty_recipients = new WP_Notify_Recipient_Collection();
-		$message          = new WP_Notify_Base_Message( 'Message' );
-		$testee           = new WP_Notify_Base_Notification(
-			$sender_mock,
-			$empty_recipients,
-			$message
-		);
-		$this->assertEquals(
-			self::JSON_SERIALIZED,
-			json_encode( $testee )
-		);
-	}
-
-	public function test_it_can_be_instantiated_from_json() {
-		$testee = WP_Notify_Base_Notification::json_unserialize( self::JSON_SERIALIZED );
-		$this->assertInstanceOf( 'WP_Notify_Base_Notification', $testee );
-		$this->assertInstanceOf(
-			'WP_Notify_Recipient_Collection',
-			$testee->get_recipients()
-		);
-		$this->assertInstanceOf(
-			'WP_Notify_Base_Message',
-			$testee->get_message()
-		);
-		$this->assertInstanceOf(
-			'WP_Notify_Base_Sender',
-			$testee->get_sender()
-		);
-	}
-}
diff --git a/tests/phpunit/tests/test-wp-notify-base-sender.php b/tests/phpunit/tests/test-wp-notify-base-sender.php
deleted file mode 100644
index 0581fb50..00000000
--- a/tests/phpunit/tests/test-wp-notify-base-sender.php
+++ /dev/null
@@ -1,70 +0,0 @@
-<?php
-
-class Test_WP_Notify_Base_Sender extends WP_Notify_TestCase {
-
-	/**
-	 * @param array  $sender_params
-	 * @param string $expected_json
-	 *
-	 * @dataProvider data_provider_senders
-	 */
-	public function test_it_can_be_json_encoded( $sender_params, $expected_json ) {
-
-		$sender_reflection = new ReflectionClass( 'WP_Notify_Base_Sender' );
-		$sender            = $sender_reflection->newInstanceArgs( array_values( $sender_params ) );
-
-		$sender_encoded = json_encode( $sender );
-
-		$this->assertEquals( $expected_json, $sender_encoded );
-	}
-
-	/**
-	 * @param array  $sender_params
-	 * @param string $json
-	 *
-	 * @dataProvider data_provider_senders
-	 */
-	public function test_it_can_be_instantiated_from_json( $sender_params, $json ) {
-
-		$testee = WP_Notify_Base_Sender::json_unserialize( $json );
-
-		$sender_reflection = new ReflectionClass( 'WP_Notify_Base_Sender' );
-		/** @var WP_Notify_Base_Sender $sender */
-		$sender = $sender_reflection->newInstanceArgs( array_values( (array) $sender_params ) );
-
-		$this->assertInstanceOf( 'WP_Notify_Base_Sender', $testee );
-		$this->assertEquals( $sender->get_name(), $testee->get_name() );
-
-		$this->assertEquals( $sender->get_image(), $testee->get_image() );
-
-		/**
-		 * If an Image has been sent
-		 */
-		if ( $testee->get_image() ) {
-			$this->assertInstanceOf( get_class( $sender->get_image() ), $testee->get_image() );
-			$this->assertEquals( $sender->get_image()->get_source(), $testee->get_image()->get_source() );
-			$this->assertEquals( $sender->get_image()->get_alt(), $testee->get_image()->get_alt() );
-		}
-	}
-
-	public function data_provider_senders() {
-
-		return array(
-
-			'sender without image' => array(
-				array(
-					'Name 1',
-				),
-				'{"name":"Name 1"}',
-			),
-
-			'sender with image'    => array(
-				array(
-					'name'                 => 'Name 2',
-					'WP_Notify_Base_Image' => new WP_Notify_Base_Image( 'img-source', 'img-alt' ),
-				),
-				'{"name":"Name 2","WP_Notify_Base_Image":{"source":"img-source","alt":"img-alt"}}',
-			),
-		);
-	}
-}
diff --git a/tests/phpunit/tests/test-wp-notify-recipient-collection.php b/tests/phpunit/tests/test-wp-notify-recipient-collection.php
deleted file mode 100644
index c9a93c93..00000000
--- a/tests/phpunit/tests/test-wp-notify-recipient-collection.php
+++ /dev/null
@@ -1,93 +0,0 @@
-<?php
-
-class Test_WP_Notify_Recipient_Collection extends WP_Notify_TestCase {
-
-	const SERIALIZED = 'C:28:"WPNotify_RecipientCollection":6:{a:0:{}}';
-
-	public function test_it_can_be_instantiated() {
-		$testee = new WP_Notify_Recipient_Collection();
-		$this->assertInstanceOf( 'WP_Notify_Recipient_Collection', $testee );
-	}
-
-	public function test_it_is_countable() {
-		$testee = new WP_Notify_Recipient_Collection();
-		$this->assertInstanceOf( 'Countable', $testee );
-	}
-
-	public function test_it_is_traversable() {
-		$testee = new WP_Notify_Recipient_Collection();
-		$this->assertInstanceOf( 'Traversable', $testee );
-	}
-
-	public function test_it_is_empty_when_instantiated_without_arguments() {
-		$testee = new WP_Notify_Recipient_Collection();
-		$this->assertCount( 0, $testee );
-	}
-
-	public function test_it_can_accept_a_singular_recipient() {
-		$mock_recipient = $this->createMock( 'WP_Notify_Recipient' );
-		$testee         = new WP_Notify_Recipient_Collection( $mock_recipient );
-		$this->assertCount( 1, $testee );
-	}
-
-	public function test_it_can_accept_an_array_of_recipients() {
-		$mock_recipient_1 = $this->createMock( 'WP_Notify_Recipient' );
-		$mock_recipient_2 = $this->createMock( 'WP_Notify_Recipient' );
-		$mock_recipient_3 = $this->createMock( 'WP_Notify_Recipient' );
-		$testee           = new WP_Notify_Recipient_Collection(
-			array(
-				$mock_recipient_1,
-				$mock_recipient_2,
-				$mock_recipient_3,
-			)
-		);
-		$this->assertCount( 3, $testee );
-	}
-
-	public function test_recipients_can_be_added() {
-		$mock_recipient_1 = $this->createMock( 'WP_Notify_Recipient' );
-		$mock_recipient_2 = $this->createMock( 'WP_Notify_Recipient' );
-		$mock_recipient_3 = $this->createMock( 'WP_Notify_Recipient' );
-		$testee           = new WP_Notify_Recipient_Collection( $mock_recipient_1 );
-		$this->assertCount( 1, $testee );
-		$testee->add( $mock_recipient_2 );
-		$this->assertCount( 2, $testee );
-		$testee->add( $mock_recipient_3 );
-		$this->assertCount( 3, $testee );
-	}
-
-	/** @dataProvider data_provider_it_throws_on_invalid_type */
-	public function test_it_throws_on_invalid_type( $invalid_recipient ) {
-		$this->expectException( 'WP_Notify_Runtime_Exception' );
-		new WP_Notify_Recipient_Collection( $invalid_recipient );
-	}
-
-	public function data_provider_it_throws_on_invalid_type() {
-		$mock_recipient_1 = $this->createMock( 'WP_Notify_Recipient' );
-		$mock_recipient_2 = $this->createMock( 'WP_Notify_Recipient' );
-
-		return array(
-			array( null ),
-			array( true ),
-			array( new stdClass ),
-			array( 'invalid' ),
-			array( array( 1, 2, 3 ) ),
-			array( array( $mock_recipient_1, 'invalid', $mock_recipient_2 ) ),
-		);
-	}
-
-	public function test_it_can_be_json_encoded() {
-		$testee = new WP_Notify_Recipient_Collection( array() );
-		$this->assertEquals(
-			'[]',
-			json_encode( $testee )
-		);
-	}
-
-	public function test_it_can_be_instantiated_from_json() {
-		$json   = '[]';
-		$testee = WP_Notify_Recipient_Collection::json_unserialize( $json );
-		$this->assertInstanceOf( 'WP_Notify_Recipient_Collection', $testee );
-		$this->assertEquals( 0, $testee->count() );
-	}
-}
diff --git a/tests/phpunit/tests/test-wp-notify-role-recipient.php b/tests/phpunit/tests/test-wp-notify-role-recipient.php
deleted file mode 100644
index 194e3d28..00000000
--- a/tests/phpunit/tests/test-wp-notify-role-recipient.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-class Test_WP_Notify_Role_Recipient extends WP_Notify_TestCase {
-
-	public function test_it_can_be_instantiated() {
-		$testee = new WP_Notify_Role_Recipient( 1 );
-		$this->assertInstanceOf( 'WP_Notify_Role_Recipient', $testee );
-	}
-
-	public function test_it_implements_the_interface() {
-		$testee = new WP_Notify_Role_Recipient( 1 );
-		$this->assertInstanceOf( 'WP_Notify_Recipient', $testee );
-	}
-}
diff --git a/tests/phpunit/tests/test-wp-notify-user-recipient.php b/tests/phpunit/tests/test-wp-notify-user-recipient.php
deleted file mode 100644
index 5a6497f5..00000000
--- a/tests/phpunit/tests/test-wp-notify-user-recipient.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php
-
-class Test_WP_Notify_User_Recipient extends WP_Notify_TestCase {
-
-	public function test_it_can_be_instantiated() {
-		$testee = new WP_Notify_User_Recipient( 1 );
-		$this->assertInstanceOf( 'WP_Notify_User_Recipient', $testee );
-	}
-
-	public function test_it_implements_the_recipient_interface() {
-		$testee = new WP_Notify_User_Recipient( 1 );
-		$this->assertInstanceOf( 'WP_Notify_Recipient', $testee );
-	}
-
-	public function test_it_accepts_a_user_id_as_a_string() {
-		$testee = new WP_Notify_User_Recipient( '1' );
-		$this->assertInstanceOf( 'WP_Notify_Recipient', $testee );
-	}
-
-	/** @dataProvider data_provider_it_throws_on_invalid_type */
-	public function test_it_throws_on_invalid_type( $invalid_user_id ) {
-		$this->expectException( 'WP_Notify_Invalid_Recipient' );
-		new WP_Notify_User_Recipient( $invalid_user_id );
-	}
-
-	public function data_provider_it_throws_on_invalid_type() {
-		return array(
-			array( null ),
-			array( - 1 ),
-			array( 0 ),
-			array( 'invalid' ),
-			array( new stdClass ),
-			array( array( 1, 2 ) ),
-		);
-	}
-}
diff --git a/wp-feature-notifications.php b/wp-feature-notifications.php
index 94764b3e..0132681f 100644
--- a/wp-feature-notifications.php
+++ b/wp-feature-notifications.php
@@ -15,52 +15,53 @@
  * @package wp-feature-notifications
  */
 
+namespace WP\Notifications;
+
 use WP\Notifications\REST;
 
-if ( ! defined( 'WP_NOTIFICATION_CENTER_PLUGIN_VERSION' ) ) {
-	define( 'WP_NOTIFICATION_CENTER_PLUGIN_VERSION', '0.0.1' );
+if ( ! defined( 'WP_FEATURE_NOTIFICATION_PLUGIN_VERSION' ) ) {
+	define( 'WP_FEATURE_NOTIFICATION_PLUGIN_VERSION', '0.0.1' );
 }
 
-if ( ! defined( 'WP_NOTIFICATION_CENTER_PLUGIN_DIR' ) ) {
-	define( 'WP_NOTIFICATION_CENTER_PLUGIN_DIR', dirname( __FILE__ ) );
+if ( ! defined( 'WP_FEATURE_NOTIFICATION_PLUGIN_DIR' ) ) {
+	define( 'WP_FEATURE_NOTIFICATION_PLUGIN_DIR', dirname( __FILE__ ) );
 }
 
-if ( ! defined( 'WP_NOTIFICATION_CENTER_PLUGIN_DIR_URL' ) ) {
-	define( 'WP_NOTIFICATION_CENTER_PLUGIN_DIR_URL', plugin_dir_url( __FILE__ ) );
+if ( ! defined( 'WP_FEATURE_NOTIFICATION_PLUGIN_DIR_URL' ) ) {
+	define( 'WP_FEATURE_NOTIFICATION_PLUGIN_DIR_URL', plugin_dir_url( __FILE__ ) );
 }
 
 // Require interface/class declarations..
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/exceptions/interface-wp-notify-exception.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/exceptions/class-wp-notify-runtime-exception.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/exceptions/class-wp-notify-invalid-recipient.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/exceptions/class-wp-notify-failed-to-add-recipient.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/interface-wp-notify-json-unserializable.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/interface-wp-notify-status.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/interface-wp-notify-notification.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/class-wp-notify-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/class-wp-notify-aggregate-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/class-wp-notify-base-notification.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/image/interface-wp-notify-image.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/image/class-wp-notify-base-image.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/senders/interface-wp-notify-sender.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/senders/class-wp-notify-base-sender.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/interface-wp-notify-recipient.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/class-wp-notify-recipient-collection.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/class-wp-notify-user-recipient.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/class-wp-notify-role-recipient.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/interface-wp-notify-recipient-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/class-wp-notify-base-recipient-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/recipients/class-wp-notify-aggregate-recipient-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/messages/interface-wp-notify-message.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/messages/class-wp-notify-base-message.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/messages/interface-wp-notify-message-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/messages/class-wp-notify-base-message-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/messages/class-wp-notify-aggregate-message-factory.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/persistence/interface-wp-notify-notification-repository.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/persistence/class-wp-notify-abstract-notification-repository.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/persistence/class-wp-notify-wpdb-notification-repository.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/demo.php';
-require_once WP_NOTIFICATION_CENTER_PLUGIN_DIR . '/includes/restapi/class-notification-controller.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/exceptions/interface-exception.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/exceptions/class-runtime-exception.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/exceptions/class-invalid-recipient.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/exceptions/class-failed-to-add-recipient.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/interface-json-unserializable.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/interface-status.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/interface-notification.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/class-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/class-aggregate-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/class-base-notification.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/image/interface-image.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/image/class-base-image.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/senders/interface-sender.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/senders/class-base-sender.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/interface-recipient.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/class-collection.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/class-user.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/class-role.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/interface-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/class-base-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/recipients/class-aggregate-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/messages/interface-message.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/messages/class-base-message.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/messages/interface-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/messages/class-base-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/messages/class-aggregate-factory.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/persistence/interface-notification-repository.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/persistence/class-abstract-notification-repository.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/persistence/class-wpdb-notification-repository.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/demo.php';
+require_once WP_FEATURE_NOTIFICATION_PLUGIN_DIR . '/includes/restapi/class-notification-controller.php';
 
-// TODO: Standardise structure and/or autoloading.
 new REST\Notification_Controller();