diff --git a/src/api/blog.php b/src/api/blog.php
index 2b9ebbfd..a9a378b4 100644
--- a/src/api/blog.php
+++ b/src/api/blog.php
@@ -32,7 +32,7 @@ switch ($_SERVER['REQUEST_METHOD']) {
             $html .= '<div class="item">';
             $html .= '    <i class="large rss middle aligned icon"></i>';
             $html .= '    <div class="content">';
-            $html .= '         <a class="header" href="/?page=post&slug=' . $post->slug . '">' . $post->title->rendered . '</a>';
+            $html .= '         <a class="header" href="' . Page::PAGE_POST . '&slug=' . $post->slug . '">' . $post->title->rendered . '</a>';
             $html .= '         <div class="description">' . sprintf(__('Posted on %s'), $date) . '</div>';
             $html .= '    </div>';
             $html .= '</div>';
diff --git a/src/classes/page.php b/src/classes/page.php
index ef8ca156..5b661748 100644
--- a/src/classes/page.php
+++ b/src/classes/page.php
@@ -21,9 +21,25 @@ class Page
 {
     /**
      * Static
-     *
-     * @return string
      */
+    public const PAGE_BLOG            = '/?page=blog';
+    public const PAGE_CHANGELOG       = '/?page=changelog';
+    public const PAGE_HOME            = '/?page=home';
+    public const PAGE_INSTALL         = '/?page=install';
+    public const PAGE_LOGIN_AS        = '/?page=login-as';
+    public const PAGE_LOGIN           = '/?page=login';
+    public const PAGE_LOGOUT          = '/?page=logout';
+    public const PAGE_MAINTENANCE     = '/?page=maintenance';
+    public const PAGE_POST            = '/?page=post';
+    public const PAGE_POWER           = '/?page=power';
+    public const PAGE_PROFILE         = '/?page=profile';
+    public const PAGE_REGISTER        = '/?page=register';
+    public const PAGE_SETTINGS        = '/?page=settings';
+    public const PAGE_UPDATE          = '/?page=update';
+    public const PAGE_WISHLIST        = '/?page=wishlist';
+    public const PAGE_WISHLISTS_SAVED = '/?page=wishlists-saved';
+    public const PAGE_WISHLISTS       = '/?page=wishlists';
+
     public static function message(string $content = '', string $header = '', string $type = ''): string
     {
         ob_start();
@@ -137,14 +153,14 @@ class Page
             && isset($_SESSION['_GET']['page'])
             && !in_array($_SESSION['_GET']['page'], $ignorePower)
         ) {
-            redirect('/?page=login');
+            redirect(Page::PAGE_LOGIN);
         }
 
         /**
          * Power
          */
         if (isset($user->power) && $user->power < $this->power) {
-            redirect('/?page=power&required=' . $this->power);
+            redirect(Page::PAGE_POWER . '&required=' . $this->power);
         }
 
         /**
@@ -159,9 +175,9 @@ class Page
 
         if ($options && $options->getOption('updateAvailable') && !in_array($this->name, $ignoreUpdateRedirect)) {
             if (100 === $user->power) {
-                redirect('/?page=update');
+                redirect(Page::PAGE_UPDATE);
             } else {
-                redirect('/?page=maintenance');
+                redirect(Page::PAGE_MAINTENANCE);
             }
         }
 
@@ -460,7 +476,7 @@ class Page
                 'items'     => array(
                     array(
                         'text' => __('Blog'),
-                        'url'  => '/?page=blog',
+                        'url'  => self::PAGE_BLOG,
                         'icon' => 'rss',
                     ),
                 ),
@@ -486,12 +502,12 @@ class Page
                 'items'     => array(
                     array(
                         'text' => __('My lists'),
-                        'url'  => '/?page=wishlists',
+                        'url'  => Page::PAGE_WISHLISTS,
                         'icon' => 'list',
                     ),
                     array(
                         'text' => __('Saved lists'),
-                        'url'  => '/?page=wishlists-saved',
+                        'url'  => Page::PAGE_WISHLISTS_SAVED,
                         'icon' => 'heart',
                     ),
                 ),
@@ -501,19 +517,19 @@ class Page
         if ($user->isLoggedIn()) {
             $pages[$account]['items'][] = array(
                 'text' => __('Profile'),
-                'url'  => '/?page=profile',
+                'url'  => Page::PAGE_PROFILE,
                 'icon' => 'user circle alternate',
             );
             if (100 === $user->power) {
                 $pages[$account]['items'][] = array(
                     'text' => __('Login as'),
-                    'url'  => '/?page=login-as',
+                    'url'  => Page::PAGE_LOGIN_AS,
                     'icon' => 'sign out alternate',
                 );
             }
             $pages[$account]['items'][] = array(
                 'text' => __('Logout'),
-                'url'  => '/?page=logout',
+                'url'  => Page::PAGE_LOGOUT,
                 'icon' => 'sign out alternate',
             );
         } else {
@@ -523,7 +539,7 @@ class Page
                 'items'     => array(
                     array(
                         'text' => __('Login'),
-                        'url'  => '/?page=login',
+                        'url'  => Page::PAGE_LOGIN,
                         'icon' => 'sign in alternate',
                     )
                 ),
@@ -534,7 +550,7 @@ class Page
                 'items'     => array(
                     array(
                         'text' => __('Register'),
-                        'url'  => '/?page=register',
+                        'url'  => Page::PAGE_REGISTER,
                         'icon' => 'user plus alternate',
                     )
                 ),
@@ -544,7 +560,7 @@ class Page
         if (isset($user->power) && 100 === $user->power) {
             $pages[$system]['items'][] = array(
                 'text' => __('Settings'),
-                'url'  => '/?page=settings',
+                'url'  => Page::PAGE_SETTINGS,
                 'icon' => 'cog',
             );
         }
@@ -557,7 +573,7 @@ class Page
         <div class="ui attached stackable vertical menu sidebar">
             <div class="ui container">
 
-                <a class="item home" href="/?page=home"><?= $svgLogo ?></a>
+                <a class="item home" href="<?= Page::PAGE_HOME ?>"><?= $svgLogo ?></a>
 
                 <?php foreach ($pages as $page) { ?>
                     <?php foreach ($page['items'] as $item) { ?>
@@ -574,7 +590,7 @@ class Page
         <div class="pusher">
             <div class="ui attached menu desktop">
                 <div class="ui container">
-                    <a class="item home" href="/?page=home"><?= $svgLogo ?></a>
+                    <a class="item home" href="<?= Page::PAGE_HOME ?>"><?= $svgLogo ?></a>
 
                     <?php foreach ($pages as $page) { ?>
                         <?php if ('left' === $page['alignment']) { ?>
@@ -685,7 +701,7 @@ class Page
                             </div>
 
                             <a class="item"
-                               href="/?page=changelog"
+                               href="<?= Page::PAGE_CHANGELOG ?>"
                                title="<?= __('Changelog') ?>"
                             >
                                 <i class="newspaper icon"></i>
diff --git a/src/pages/blog.php b/src/pages/blog.php
index 3199af17..b51ccedf 100644
--- a/src/pages/blog.php
+++ b/src/pages/blog.php
@@ -32,7 +32,7 @@ $posts = Blog::getPosts();
                 );
                 $mediaHTML      = isset($post->featured_media) ? Blog::getMediaHTML($post->featured_media) : '';
                 $categoriesHTML = Blog::getCategoriesHTML($post->categories);
-                $postLink       = '/?page=post&slug=' . $post->slug;
+                $postLink       = Page::PAGE_POST . '&slug=' . $post->slug;
                 ?>
                 <div class="column">
                     <div class="ui fluid card stretch">
diff --git a/src/pages/home.php b/src/pages/home.php
index 3c7d4f3b..563b8041 100644
--- a/src/pages/home.php
+++ b/src/pages/home.php
@@ -29,7 +29,7 @@ $page->navigation();
                         <?php if ($user->isLoggedIn()) { ?>
                             <div class="column">
                                 <a class="ui fluid primary button"
-                                href="/?page=wishlists"
+                                href="<?= Page::PAGE_WISHLISTS ?>"
                                 title="<?= __('My lists') ?>"
                                 >
                                     <?= __('My lists') ?>
@@ -38,7 +38,7 @@ $page->navigation();
                         <?php } else { ?>
                             <div class="column">
                                 <a class="ui fluid primary button"
-                                href="/?page=register"
+                                href="<?= Page::PAGE_REGISTER ?>"
                                 title="<?= __('Register now') ?>"
                                 >
                                     <?= __('Register now') ?>
@@ -46,7 +46,7 @@ $page->navigation();
                             </div>
                             <div class="column">
                                 <a class="ui fluid button"
-                                href="/?page=login"
+                                href="<?= Page::PAGE_LOGIN ?>"
                                 title="<?= __('Login') ?>"
                                 >
                                     <?= __('Login') ?>
diff --git a/src/pages/install.php b/src/pages/install.php
index f99d0b4c..290fab89 100644
--- a/src/pages/install.php
+++ b/src/pages/install.php
@@ -9,7 +9,7 @@
 namespace wishthis;
 
 if ($options && $options->getOption('isInstalled')) {
-    redirect('/?page=home');
+    redirect(Page::PAGE_HOME);
 }
 
 $page = new Page(__FILE__, __('Install'));
@@ -31,7 +31,7 @@ switch ($step) {
                     <p><?= __('Welcome to the wishthis installer.') ?></p>
                     <p><?= __('wishthis needs a database to function properly. Please enter your credentials.') ?></p>
 
-                    <form class="ui form" action="/?page=install" method="POST">
+                    <form class="ui form" action="<?= Page::PAGE_INSTALL ?>" method="POST">
                         <input type="hidden" name="install" value="true" />
                         <input type="hidden" name="step" value="<?= $step + 1; ?>" />
 
@@ -101,7 +101,7 @@ switch ($step) {
                     <h2 class="ui header"><?= sprintf(__('Step %d'), $step) ?></h2>
                     <p><?= __('Click continue to test the database connection.') ?></p>
 
-                    <form class="ui form" action="?page=install" method="POST">
+                    <form class="ui form" action="<?= Page::PAGE_INSTALL ?>" method="POST">
                         <input type="hidden" name="install" value="true" />
                         <input type="hidden" name="step" value="<?= $step + 1; ?>" />
 
@@ -229,7 +229,7 @@ switch ($step) {
                     <h1 class="ui header"><?= __('Success') ?></h1>
                     <p>
                         <a class="ui primary button"
-                           href="/?page=register"
+                           href="<? Page::PAGE_REGISTER ?>"
                            title="<?= __('Register') ?>"
                         >
                             <?= __('Register') ?>
diff --git a/src/pages/login.php b/src/pages/login.php
index 109fd1f7..0e3ba3f2 100644
--- a/src/pages/login.php
+++ b/src/pages/login.php
@@ -40,7 +40,7 @@ if (isset($_POST['login'], $_POST['email'], $_POST['password'])) {
 }
 
 if (isset($_SESSION['user'])) {
-    redirect('/?page=home');
+    redirect(Page::PAGE_HOME);
 }
 
 /**
@@ -89,7 +89,7 @@ if (isset($_POST['reset'], $_POST['email'])) {
             'password-reset-link',
             $_SERVER['REQUEST_SCHEME'] . '://' .
             $_SERVER['HTTP_HOST'] .
-            '/?page=register&password-reset=' . $_POST['email'] . '&token=' . $token,
+            Page::PAGE_REGISTER . '&password-reset=' . $_POST['email'] . '&token=' . $token,
             $mjml
         );
 
@@ -146,7 +146,7 @@ $page->navigation();
                                    title="<?= __('Login') ?>"
                             />
                             <a class="ui tertiary button"
-                               href="/?page=register"
+                               href="<?= Page::PAGE_REGISTER ?>"
                                title="<?= __('Register') ?>"
                             >
                                 <?= __('Register') ?>
diff --git a/src/pages/logout.php b/src/pages/logout.php
index 346af798..a4c1cda5 100644
--- a/src/pages/logout.php
+++ b/src/pages/logout.php
@@ -13,7 +13,7 @@ $page = new Page(__FILE__, __('Logout'));
 if (PHP_SESSION_ACTIVE === session_status()) {
     session_destroy();
 
-    redirect('/?page=home');
+    redirect(Page::PAGE_HOME);
 }
 
 $page->header();
diff --git a/src/pages/register.php b/src/pages/register.php
index 7a7ca154..3eaf4a4a 100644
--- a/src/pages/register.php
+++ b/src/pages/register.php
@@ -225,7 +225,7 @@ $page->navigation();
                                    title="<?= $buttonSubmit ?>"
                             />
                             <a class="ui tertiary button"
-                               href="/?page=login"
+                               href="<?= Page::PAGE_LOGIN ?>"
                                title="<?= __('Login') ?>"
                             >
                                 <?= __('Login') ?>
diff --git a/src/pages/wishlists-saved.php b/src/pages/wishlists-saved.php
index 09fd7d3a..1aa25982 100644
--- a/src/pages/wishlists-saved.php
+++ b/src/pages/wishlists-saved.php
@@ -28,7 +28,7 @@ $page->navigation();
                     <div class="item">
                         <i class="large heart middle aligned icon"></i>
                         <div class="content">
-                            <a class="header" href="/?page=wishlist&hash=<?= $wishlist->hash ?>"><?= $wishlist->getTitle(); ?></a>
+                            <a class="header" href="<?= Page::PAGE_WISHLIST ?>&hash=<?= $wishlist->hash ?>"><?= $wishlist->getTitle(); ?></a>
                             <div class="description"><?= $wishlist_user->getDisplayName(); ?></div>
                         </div>
                     </div>