diff --git a/functions.php b/functions.php
index ba40ad95..23ab9f75 100644
--- a/functions.php
+++ b/functions.php
@@ -523,7 +523,7 @@ if ( strpos( $_SERVER['REQUEST_URI'], 'wp-json/fictioneer/' ) !== false ) {
   require_once __DIR__ . '/includes/functions/comments/_comments_threads.php';
 }
 
-if ( is_admin() ) {
+if ( wp_doing_ajax() ) {
   // Required for AJAX
   require_once __DIR__ . '/includes/functions/comments/_comments_ajax.php';
   require_once __DIR__ . '/includes/functions/comments/_comments_form.php';
diff --git a/includes/functions/_module-epub.php b/includes/functions/_module-epub.php
index fc5d5491..4e13ebaf 100644
--- a/includes/functions/_module-epub.php
+++ b/includes/functions/_module-epub.php
@@ -1178,6 +1178,15 @@ function fictioneer_generate_epub() {
 }
 add_action( 'template_redirect', 'fictioneer_generate_epub', 10 );
 
+// =============================================================================
+// AJAX REQUESTS
+// > Return early if no AJAX functions are required.
+// =============================================================================
+
+if ( ! wp_doing_ajax() ) {
+  return;
+}
+
 // =============================================================================
 // AJAX - CHECK IF READY TO DOWNLOAD
 // =============================================================================
diff --git a/includes/functions/_utility.php b/includes/functions/_utility.php
index 22de4528..933bcc3a 100644
--- a/includes/functions/_utility.php
+++ b/includes/functions/_utility.php
@@ -1691,49 +1691,6 @@ function fictioneer_show_auth_content() {
     get_option( 'fictioneer_enable_ajax_authentication' );
 }
 
-// =============================================================================
-// AJAX AUTHENTICATION
-// =============================================================================
-
-/**
- * Send user authentication status via AJAX
- *
- * @since 5.7.0
- */
-
-function fictioneer_ajax_get_auth() {
-  // Enabled?
-  if ( ! get_option( 'fictioneer_enable_ajax_authentication' ) ) {
-    wp_send_json_error(
-      array( 'error' => __( 'Not allowed.', 'fictioneer' ) ),
-      403
-    );
-  }
-
-  // Setup
-  $user = wp_get_current_user();
-  $nonce = wp_create_nonce( 'fictioneer_nonce' );
-  $nonce_html = '<input id="fictioneer-ajax-nonce" name="fictioneer-ajax-nonce" type="hidden" value="' . $nonce . '">';
-
-  // Response
-  wp_send_json_success(
-    array(
-      'loggedIn' => is_user_logged_in(),
-      'isAdmin' => fictioneer_is_admin( $user->ID ),
-      'isModerator' => fictioneer_is_moderator( $user->ID ),
-      'isAuthor' => fictioneer_is_author( $user->ID ),
-      'isEditor' => fictioneer_is_editor( $user->ID ),
-      'nonce' => $nonce,
-      'nonceHtml' => $nonce_html
-    )
-  );
-}
-
-if ( get_option( 'fictioneer_enable_ajax_authentication' ) ) {
-  add_action( 'wp_ajax_fictioneer_ajax_get_auth', 'fictioneer_ajax_get_auth' );
-  add_action( 'wp_ajax_nopriv_fictioneer_ajax_get_auth', 'fictioneer_ajax_get_auth' );
-}
-
 // =============================================================================
 // FICTIONEER TRANSLATIONS
 // =============================================================================
@@ -3163,3 +3120,56 @@ function fictioneer_get_random_username( $unique = true ) {
   // Return username
   return $username;
 }
+
+// =============================================================================
+// AJAX REQUESTS
+// > Return early if no AJAX functions are required.
+// =============================================================================
+
+if ( ! wp_doing_ajax() ) {
+  return;
+}
+
+
+// =============================================================================
+// AJAX AUTHENTICATION
+// =============================================================================
+
+/**
+ * Send user authentication status via AJAX
+ *
+ * @since 5.7.0
+ */
+
+function fictioneer_ajax_get_auth() {
+  // Enabled?
+  if ( ! get_option( 'fictioneer_enable_ajax_authentication' ) ) {
+    wp_send_json_error(
+      array( 'error' => __( 'Not allowed.', 'fictioneer' ) ),
+      403
+    );
+  }
+
+  // Setup
+  $user = wp_get_current_user();
+  $nonce = wp_create_nonce( 'fictioneer_nonce' );
+  $nonce_html = '<input id="fictioneer-ajax-nonce" name="fictioneer-ajax-nonce" type="hidden" value="' . $nonce . '">';
+
+  // Response
+  wp_send_json_success(
+    array(
+      'loggedIn' => is_user_logged_in(),
+      'isAdmin' => fictioneer_is_admin( $user->ID ),
+      'isModerator' => fictioneer_is_moderator( $user->ID ),
+      'isAuthor' => fictioneer_is_author( $user->ID ),
+      'isEditor' => fictioneer_is_editor( $user->ID ),
+      'nonce' => $nonce,
+      'nonceHtml' => $nonce_html
+    )
+  );
+}
+
+if ( get_option( 'fictioneer_enable_ajax_authentication' ) ) {
+  add_action( 'wp_ajax_fictioneer_ajax_get_auth', 'fictioneer_ajax_get_auth' );
+  add_action( 'wp_ajax_nopriv_fictioneer_ajax_get_auth', 'fictioneer_ajax_get_auth' );
+}
diff --git a/includes/functions/users/_checkmarks.php b/includes/functions/users/_checkmarks.php
index 2e1b0b55..823dea71 100644
--- a/includes/functions/users/_checkmarks.php
+++ b/includes/functions/users/_checkmarks.php
@@ -103,6 +103,15 @@ if ( ! function_exists( 'fictioneer_count_chapter_checkmarks' ) ) {
   }
 }
 
+// =============================================================================
+// AJAX REQUESTS
+// > Return early if no AJAX functions are required.
+// =============================================================================
+
+if ( ! wp_doing_ajax() ) {
+  return;
+}
+
 // =============================================================================
 // SET CHECKMARKS - AJAX
 // =============================================================================
diff --git a/includes/functions/users/_follows.php b/includes/functions/users/_follows.php
index e9eb9977..de5df286 100644
--- a/includes/functions/users/_follows.php
+++ b/includes/functions/users/_follows.php
@@ -44,6 +44,73 @@ if ( ! function_exists( 'fictioneer_load_follows' ) ) {
   }
 }
 
+// =============================================================================
+// QUERY CHAPTERS OF FOLLOWED STORIES
+// =============================================================================
+
+if ( ! function_exists( 'fictioneer_query_followed_chapters' ) ) {
+  /**
+   * Query chapters of followed stories
+   *
+   * @since 4.3.0
+   *
+   * @param array        $story_ids   IDs of the followed stories.
+   * @param string|false $after_date  Optional. Only return chapters after this date, e.g. wp_date( 'c', $timestamp ).
+   * @param int          $count       Optional. Maximum number of chapters to be returned. Default 20.
+   *
+   * @return array Collection of chapters.
+   */
+
+  function fictioneer_query_followed_chapters( $story_ids, $after_date = false, $count = 20 ) {
+    // Setup
+    $query_args = array (
+      'post_type' => 'fcn_chapter',
+      'post_status' => 'publish',
+      'meta_query' => array(
+        array(
+          'key' => 'fictioneer_chapter_story',
+          'value' => $story_ids,
+          'compare' => 'IN',
+        )
+      ),
+      'numberposts' => $count,
+      'orderby' => 'date',
+      'order' => 'DESC',
+      'update_post_meta_cache' => true,
+      'update_post_term_cache' => false, // Improve performance
+      'no_found_rows' => true // Improve performance
+    );
+
+    if ( $after_date ) {
+      $query_args['date_query'] = array( 'after' => $after_date );
+    }
+
+    // Query
+    $all_chapters = get_posts( $query_args );
+
+    // Filter out hidden chapters (faster than meta query, highly unlikely to eliminate all)
+    $chapters = array_filter( $all_chapters, function ( $candidate ) {
+      // Chapter hidden?
+      $chapter_hidden = get_post_meta( $candidate->ID, 'fictioneer_chapter_hidden', true );
+
+      // Only keep if not hidden
+      return empty( $chapter_hidden ) || $chapter_hidden === '0';
+    });
+
+    // Return final results
+    return $chapters;
+  }
+}
+
+// =============================================================================
+// AJAX REQUESTS
+// > Return early if no AJAX functions are required.
+// =============================================================================
+
+if ( ! wp_doing_ajax() ) {
+  return;
+}
+
 // =============================================================================
 // TOGGLE FOLLOW - AJAX
 // =============================================================================
@@ -205,64 +272,6 @@ if ( get_option( 'fictioneer_enable_follows' ) ) {
   add_action( 'wp_ajax_fictioneer_ajax_mark_follows_read', 'fictioneer_ajax_mark_follows_read' );
 }
 
-// =============================================================================
-// QUERY CHAPTERS OF FOLLOWED STORIES
-// =============================================================================
-
-if ( ! function_exists( 'fictioneer_query_followed_chapters' ) ) {
-  /**
-   * Query chapters of followed stories
-   *
-   * @since 4.3.0
-   *
-   * @param array        $story_ids   IDs of the followed stories.
-   * @param string|false $after_date  Optional. Only return chapters after this date, e.g. wp_date( 'c', $timestamp ).
-   * @param int          $count       Optional. Maximum number of chapters to be returned. Default 20.
-   *
-   * @return array Collection of chapters.
-   */
-
-  function fictioneer_query_followed_chapters( $story_ids, $after_date = false, $count = 20 ) {
-    // Setup
-    $query_args = array (
-      'post_type' => 'fcn_chapter',
-      'post_status' => 'publish',
-      'meta_query' => array(
-        array(
-          'key' => 'fictioneer_chapter_story',
-          'value' => $story_ids,
-          'compare' => 'IN',
-        )
-      ),
-      'numberposts' => $count,
-      'orderby' => 'date',
-      'order' => 'DESC',
-      'update_post_meta_cache' => true,
-      'update_post_term_cache' => false, // Improve performance
-      'no_found_rows' => true // Improve performance
-    );
-
-    if ( $after_date ) {
-      $query_args['date_query'] = array( 'after' => $after_date );
-    }
-
-    // Query
-    $all_chapters = get_posts( $query_args );
-
-    // Filter out hidden chapters (faster than meta query, highly unlikely to eliminate all)
-    $chapters = array_filter( $all_chapters, function ( $candidate ) {
-      // Chapter hidden?
-      $chapter_hidden = get_post_meta( $candidate->ID, 'fictioneer_chapter_hidden', true );
-
-      // Only keep if not hidden
-      return empty( $chapter_hidden ) || $chapter_hidden === '0';
-    });
-
-    // Return final results
-    return $chapters;
-  }
-}
-
 // =============================================================================
 // GET FOLLOWS NOTIFICATIONS - AJAX
 // =============================================================================
diff --git a/includes/functions/users/_reminders.php b/includes/functions/users/_reminders.php
index ee47e458..a75cd59a 100644
--- a/includes/functions/users/_reminders.php
+++ b/includes/functions/users/_reminders.php
@@ -39,6 +39,15 @@ if ( ! function_exists( 'fictioneer_load_reminders' ) ) {
   }
 }
 
+// =============================================================================
+// AJAX REQUESTS
+// > Return early if no AJAX functions are required.
+// =============================================================================
+
+if ( ! wp_doing_ajax() ) {
+  return;
+}
+
 // =============================================================================
 // TOGGLE REMINDER - AJAX
 // =============================================================================