diff --git a/activitypub.php b/activitypub.php
index c07103e3a..b15eedc35 100644
--- a/activitypub.php
+++ b/activitypub.php
@@ -80,6 +80,7 @@ function plugin_init() {
 	\add_action( 'init', array( __NAMESPACE__ . '\Migration', 'init' ), 1 );
 	\add_action( 'init', array( __NAMESPACE__ . '\Move', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Options', 'init' ) );
+	\add_action( 'init', array( __NAMESPACE__ . '\Post_Types', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Scheduler', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Search', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Signature', 'init' ) );
diff --git a/includes/class-activitypub.php b/includes/class-activitypub.php
index b1e1bb0e4..d2af98adb 100644
--- a/includes/class-activitypub.php
+++ b/includes/class-activitypub.php
@@ -7,14 +7,10 @@
 
 namespace Activitypub;
 
-use Activitypub\Activity\Activity;
 use Activitypub\Collection\Actors;
-use Activitypub\Collection\Extra_Fields;
 use Activitypub\Collection\Followers;
 use Activitypub\Collection\Following;
-use Activitypub\Collection\Inbox;
 use Activitypub\Collection\Outbox;
-use Activitypub\Collection\Remote_Actors;
 
 /**
  * ActivityPub Class.
@@ -29,9 +25,6 @@ public static function init() {
 		\add_action( 'init', array( self::class, 'add_rewrite_rules' ), 11 );
 		\add_action( 'init', array( self::class, 'theme_compat' ), 11 );
 		\add_action( 'init', array( self::class, 'register_user_meta' ), 11 );
-		\add_action( 'init', array( self::class, 'register_post_types' ), 11 );
-
-		\add_action( 'rest_api_init', array( self::class, 'register_ap_actor_rest_field' ) );
 
 		\add_filter( 'template_include', array( self::class, 'render_activitypub_template' ), 99 );
 		\add_action( 'template_redirect', array( self::class, 'template_redirect' ) );
@@ -45,18 +38,8 @@ public static function init() {
 
 		\add_action( 'user_register', array( self::class, 'user_register' ) );
 
-		\add_filter( 'add_post_metadata', array( self::class, 'prevent_empty_post_meta' ), 10, 4 );
-		\add_filter( 'update_post_metadata', array( self::class, 'prevent_empty_post_meta' ), 10, 4 );
-		\add_filter( 'default_post_metadata', array( self::class, 'default_post_metadata' ), 10, 3 );
-
-		\add_filter( 'activitypub_get_actor_extra_fields', array( Extra_Fields::class, 'default_actor_extra_fields' ), 10, 2 );
 		\add_action( 'activitypub_add_user_block', array( Followers::class, 'remove_blocked_actors' ), 10, 3 );
 		\add_action( 'activitypub_add_user_block', array( Following::class, 'remove_blocked_actors' ), 10, 3 );
-
-		// Add support for ActivityPub to custom post types.
-		foreach ( \get_option( 'activitypub_support_post_types', array( 'post' ) ) as $post_type ) {
-			\add_post_type_support( $post_type, 'activitypub' );
-		}
 	}
 
 	/**
@@ -471,369 +454,6 @@ public static function theme_compat() {
 		}
 	}
 
-	/**
-	 * Register Custom Post Types.
-	 */
-	public static function register_post_types() {
-		\register_post_type(
-			Remote_Actors::POST_TYPE,
-			array(
-				'labels'           => array(
-					'name'          => _x( 'Followers', 'post_type plural name', 'activitypub' ),
-					'singular_name' => _x( 'Follower', 'post_type single name', 'activitypub' ),
-				),
-				'public'           => false,
-				'show_in_rest'     => true,
-				'hierarchical'     => false,
-				'rewrite'          => false,
-				'query_var'        => false,
-				'delete_with_user' => false,
-				'can_export'       => true,
-				'supports'         => array(),
-			)
-		);
-
-		\register_post_meta(
-			Remote_Actors::POST_TYPE,
-			'_activitypub_inbox',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'sanitize_callback' => 'sanitize_url',
-			)
-		);
-
-		\register_post_meta(
-			Remote_Actors::POST_TYPE,
-			'_activitypub_errors',
-			array(
-				'type'              => 'string',
-				'single'            => false,
-				'sanitize_callback' => function ( $value ) {
-					if ( ! is_string( $value ) ) {
-						throw new \Exception( 'Error message is no valid string' );
-					}
-
-					return esc_sql( $value );
-				},
-			)
-		);
-
-		\register_post_meta(
-			Remote_Actors::POST_TYPE,
-			Followers::FOLLOWER_META_KEY,
-			array(
-				'type'              => 'string',
-				'single'            => false,
-				'sanitize_callback' => function ( $value ) {
-					return esc_sql( $value );
-				},
-			)
-		);
-
-		// Register Inbox Post-Type.
-		\register_post_type(
-			Inbox::POST_TYPE,
-			array(
-				'labels'              => array(
-					'name'          => _x( 'Inbox', 'post_type plural name', 'activitypub' ),
-					'singular_name' => _x( 'Inbox Item', 'post_type single name', 'activitypub' ),
-				),
-				'capabilities'        => array(
-					'create_posts' => false,
-				),
-				'map_meta_cap'        => true,
-				'public'              => false,
-				'show_in_rest'        => true,
-				'rewrite'             => false,
-				'query_var'           => false,
-				'supports'            => array( 'title', 'editor', 'author', 'custom-fields' ),
-				'delete_with_user'    => true,
-				'can_export'          => true,
-				'exclude_from_search' => true,
-			)
-		);
-
-		// Register Inbox Post-Meta.
-		\register_post_meta(
-			Inbox::POST_TYPE,
-			'_activitypub_object_id',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'description'       => 'The ID (ActivityPub URI) of the object that the inbox item is about.',
-				'sanitize_callback' => 'sanitize_url',
-			)
-		);
-
-		\register_post_meta(
-			Inbox::POST_TYPE,
-			'_activitypub_activity_type',
-			array(
-				'type'              => 'string',
-				'description'       => 'The type of the activity',
-				'single'            => true,
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$value  = ucfirst( strtolower( $value ) );
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => Activity::TYPES,
-						'default' => 'Create',
-					);
-
-					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		\register_post_meta(
-			Inbox::POST_TYPE,
-			'_activitypub_activity_actor',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'description'       => 'The type of the local actor that received the activity.',
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => array( 'application', 'blog', 'user' ),
-						'default' => 'user',
-					);
-
-					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		\register_post_meta(
-			Inbox::POST_TYPE,
-			'_activitypub_activity_remote_actor',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'description'       => 'The ID (ActivityPub URI) of the remote actor that sent the activity.',
-				'sanitize_callback' => 'sanitize_url',
-			)
-		);
-
-		\register_post_meta(
-			Inbox::POST_TYPE,
-			'activitypub_content_visibility',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'description'       => 'The visibility of the content.',
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => array( 'public', 'unlisted', 'private', 'direct' ),
-						'default' => 'public',
-					);
-
-					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		// Register Outbox Post-Type.
-		\register_post_type(
-			Outbox::POST_TYPE,
-			array(
-				'labels'              => array(
-					'name'          => _x( 'Outbox', 'post_type plural name', 'activitypub' ),
-					'singular_name' => _x( 'Outbox Item', 'post_type single name', 'activitypub' ),
-				),
-				'capabilities'        => array(
-					'create_posts' => false,
-				),
-				'map_meta_cap'        => true,
-				'public'              => false,
-				'show_in_rest'        => true,
-				'rewrite'             => false,
-				'query_var'           => false,
-				'supports'            => array( 'title', 'editor', 'author', 'custom-fields' ),
-				'delete_with_user'    => true,
-				'can_export'          => true,
-				'exclude_from_search' => true,
-			)
-		);
-
-		/**
-		 * Register Activity Type meta for Outbox items.
-		 *
-		 * @see https://www.w3.org/TR/activitystreams-vocabulary/#activity-types
-		 */
-		\register_post_meta(
-			Outbox::POST_TYPE,
-			'_activitypub_activity_type',
-			array(
-				'type'              => 'string',
-				'description'       => 'The type of the activity',
-				'single'            => true,
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$value  = ucfirst( strtolower( $value ) );
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => Activity::TYPES,
-						'default' => 'Announce',
-					);
-
-					if ( is_wp_error( rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		\register_post_meta(
-			Outbox::POST_TYPE,
-			'_activitypub_activity_actor',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => array( 'application', 'blog', 'user' ),
-						'default' => 'user',
-					);
-
-					if ( is_wp_error( rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		\register_post_meta(
-			Outbox::POST_TYPE,
-			'_activitypub_outbox_offset',
-			array(
-				'type'              => 'integer',
-				'single'            => true,
-				'description'       => 'Keeps track of the followers offset when processing outbox items.',
-				'sanitize_callback' => 'absint',
-				'default'           => 0,
-			)
-		);
-
-		\register_post_meta(
-			Outbox::POST_TYPE,
-			'_activitypub_object_id',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'description'       => 'The ID (ActivityPub URI) of the object that the outbox item is about.',
-				'sanitize_callback' => 'sanitize_url',
-			)
-		);
-
-		\register_post_meta(
-			Outbox::POST_TYPE,
-			'activitypub_content_visibility',
-			array(
-				'type'              => 'string',
-				'single'            => true,
-				'show_in_rest'      => true,
-				'sanitize_callback' => function ( $value ) {
-					$schema = array(
-						'type'    => 'string',
-						'enum'    => array( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL ),
-						'default' => ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
-					);
-
-					if ( is_wp_error( rest_validate_enum( $value, $schema, '' ) ) ) {
-						return $schema['default'];
-					}
-
-					return $value;
-				},
-			)
-		);
-
-		// Both User and Blog Extra Fields types have the same args.
-		$extra_field_args = array(
-			'labels'              => array(
-				'name'          => _x( 'Extra fields', 'post_type plural name', 'activitypub' ),
-				'singular_name' => _x( 'Extra field', 'post_type single name', 'activitypub' ),
-				'add_new'       => __( 'Add new', 'activitypub' ),
-				'add_new_item'  => __( 'Add new extra field', 'activitypub' ),
-				'new_item'      => __( 'New extra field', 'activitypub' ),
-				'edit_item'     => __( 'Edit extra field', 'activitypub' ),
-				'view_item'     => __( 'View extra field', 'activitypub' ),
-				'all_items'     => __( 'All extra fields', 'activitypub' ),
-			),
-			'public'              => false,
-			'hierarchical'        => false,
-			'query_var'           => false,
-			'has_archive'         => false,
-			'publicly_queryable'  => false,
-			'show_in_menu'        => false,
-			'delete_with_user'    => true,
-			'can_export'          => true,
-			'exclude_from_search' => true,
-			'show_in_rest'        => true,
-			'map_meta_cap'        => true,
-			'show_ui'             => true,
-			'supports'            => array( 'title', 'editor', 'page-attributes' ),
-		);
-
-		\register_post_type( Extra_Fields::USER_POST_TYPE, $extra_field_args );
-		\register_post_type( Extra_Fields::BLOG_POST_TYPE, $extra_field_args );
-
-		/**
-		 * Fires after ActivityPub custom post types have been registered.
-		 */
-		\do_action( 'activitypub_after_register_post_type' );
-	}
-
-	/**
-	 * Register REST field for ap_actor posts.
-	 */
-	public static function register_ap_actor_rest_field() {
-		\register_rest_field(
-			Remote_Actors::POST_TYPE,
-			'activitypub_json',
-			array(
-				/**
-				 * Get the raw post content without WordPress content filtering.
-				 *
-				 * @param array $response Prepared response array.
-				 * @return string The raw post content.
-				 */
-				'get_callback' => function ( $response ) {
-					return \get_post_field( 'post_content', $response['id'] );
-				},
-				'schema'       => array(
-					'description' => 'Raw ActivityPub JSON data without WordPress content filtering',
-					'type'        => 'string',
-					'context'     => array( 'view', 'edit' ),
-				),
-			)
-		);
-	}
-
 	/**
 	 * Add the 'activitypub' capability to users who can publish posts.
 	 *
@@ -846,67 +466,6 @@ public static function user_register( $user_id ) {
 		}
 	}
 
-	/**
-	 * Prevent empty or default meta values.
-	 *
-	 * @param null|bool $check      Whether to allow updating metadata for the given type.
-	 * @param int       $object_id  ID of the object metadata is for.
-	 * @param string    $meta_key   Metadata key.
-	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.
-	 */
-	public static function prevent_empty_post_meta( $check, $object_id, $meta_key, $meta_value ) {
-		$post_metas = array(
-			'activitypub_content_visibility'       => '',
-			'activitypub_content_warning'          => '',
-			'activitypub_interaction_policy_quote' => ACTIVITYPUB_INTERACTION_POLICY_ANYONE,
-			'activitypub_max_image_attachments'    => (string) \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ),
-		);
-
-		if ( isset( $post_metas[ $meta_key ] ) && $post_metas[ $meta_key ] === (string) $meta_value ) {
-			if ( 'update_post_metadata' === current_action() ) {
-				\delete_post_meta( $object_id, $meta_key );
-			}
-
-			$check = true;
-		}
-
-		return $check;
-	}
-
-	/**
-	 * Adjusts default post meta values.
-	 *
-	 * @param mixed  $meta_value The meta value.
-	 * @param int    $object_id  ID of the object metadata is for.
-	 * @param string $meta_key   Metadata key.
-	 *
-	 * @return mixed The meta value.
-	 */
-	public static function default_post_metadata( $meta_value, $object_id, $meta_key ) {
-		// Check if the meta key is `activitypub_content_visibility`.
-		if ( 'activitypub_content_visibility' !== $meta_key ) {
-			return $meta_value;
-		}
-
-		// If meta value is already explicitly set, respect the author's choice.
-		if ( null !== $meta_value ) {
-			return $meta_value;
-		}
-
-		// If the post is federated, return the default visibility.
-		if ( 'federated' === \get_post_meta( $object_id, 'activitypub_status', true ) ) {
-			return $meta_value;
-		}
-
-		// If the post is not federated and older than a year, return local visibility.
-		$date = \get_the_date( 'U', $object_id );
-		if ( $date < \strtotime( '-1 month' ) ) {
-			return ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL;
-		}
-
-		return $meta_value;
-	}
-
 	/**
 	 * Register user meta.
 	 */
@@ -950,7 +509,7 @@ public static function register_user_meta() {
 			$blog_prefix . 'activitypub_description',
 			array(
 				'type'              => 'string',
-				'description'       => 'The user’s description.',
+				'description'       => 'The user description.',
 				'single'            => true,
 				'default'           => '',
 				'sanitize_callback' => function ( $value ) {
@@ -964,7 +523,7 @@ public static function register_user_meta() {
 			$blog_prefix . 'activitypub_icon',
 			array(
 				'type'              => 'integer',
-				'description'       => 'The attachment ID for user’s profile image.',
+				'description'       => 'The attachment ID for user profile image.',
 				'single'            => true,
 				'default'           => 0,
 				'sanitize_callback' => 'absint',
@@ -976,7 +535,7 @@ public static function register_user_meta() {
 			$blog_prefix . 'activitypub_header_image',
 			array(
 				'type'              => 'integer',
-				'description'       => 'The attachment ID for the user’s header image.',
+				'description'       => 'The attachment ID for the user header image.',
 				'single'            => true,
 				'default'           => 0,
 				'sanitize_callback' => 'absint',
diff --git a/includes/class-blocks.php b/includes/class-blocks.php
index 5d574422c..4c1a2430e 100644
--- a/includes/class-blocks.php
+++ b/includes/class-blocks.php
@@ -23,7 +23,6 @@ public static function init() {
 		\add_action( 'load-post-new.php', array( self::class, 'handle_in_reply_to_get_param' ) );
 		// Add editor plugin.
 		\add_action( 'enqueue_block_editor_assets', array( self::class, 'enqueue_editor_assets' ) );
-		\add_action( 'init', array( self::class, 'register_postmeta' ), 11 );
 		\add_action( 'rest_api_init', array( self::class, 'register_rest_fields' ) );
 
 		\add_filter( 'activitypub_import_mastodon_post_data', array( self::class, 'filter_import_mastodon_post_data' ), 10, 2 );
@@ -32,83 +31,6 @@ public static function init() {
 		\add_filter( 'activitypub_the_content', array( self::class, 'remove_post_transformation_callbacks' ) );
 	}
 
-	/**
-	 * Register post meta for content warnings.
-	 */
-	public static function register_postmeta() {
-		$ap_post_types = \get_post_types_by_support( 'activitypub' );
-		foreach ( $ap_post_types as $post_type ) {
-			\register_post_meta(
-				$post_type,
-				'activitypub_content_warning',
-				array(
-					'show_in_rest'      => true,
-					'single'            => true,
-					'type'              => 'string',
-					'sanitize_callback' => 'sanitize_text_field',
-				)
-			);
-
-			\register_post_meta(
-				$post_type,
-				'activitypub_content_visibility',
-				array(
-					'type'              => 'string',
-					'single'            => true,
-					'show_in_rest'      => true,
-					'sanitize_callback' => function ( $value ) {
-						$schema = array(
-							'type'    => 'string',
-							'enum'    => array( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL ),
-							'default' => ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
-						);
-
-						if ( is_wp_error( rest_validate_enum( $value, $schema, '' ) ) ) {
-							return $schema['default'];
-						}
-
-						return $value;
-					},
-				)
-			);
-
-			\register_post_meta(
-				$post_type,
-				'activitypub_max_image_attachments',
-				array(
-					'type'              => 'integer',
-					'single'            => true,
-					'show_in_rest'      => true,
-					'default'           => \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ),
-					'sanitize_callback' => 'absint',
-				)
-			);
-
-			\register_post_meta(
-				$post_type,
-				'activitypub_interaction_policy_quote',
-				array(
-					'type'              => 'string',
-					'single'            => true,
-					'show_in_rest'      => true,
-					'sanitize_callback' => function ( $value ) {
-						$schema = array(
-							'type'    => 'string',
-							'enum'    => array( ACTIVITYPUB_INTERACTION_POLICY_ANYONE, ACTIVITYPUB_INTERACTION_POLICY_FOLLOWERS, ACTIVITYPUB_INTERACTION_POLICY_ME ),
-							'default' => ACTIVITYPUB_INTERACTION_POLICY_ANYONE,
-						);
-
-						if ( is_wp_error( rest_validate_enum( $value, $schema, '' ) ) ) {
-							return $schema['default'];
-						}
-
-						return $value;
-					},
-				)
-			);
-		}
-	}
-
 	/**
 	 * Enqueue the block editor assets.
 	 */
diff --git a/includes/class-post-types.php b/includes/class-post-types.php
new file mode 100644
index 000000000..d45ce83f2
--- /dev/null
+++ b/includes/class-post-types.php
@@ -0,0 +1,548 @@
+<?php
+/**
+ * Post Types class for consolidating all custom post type and related meta registrations.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub;
+
+use Activitypub\Activity\Activity;
+use Activitypub\Collection\Extra_Fields;
+use Activitypub\Collection\Followers;
+use Activitypub\Collection\Inbox;
+use Activitypub\Collection\Outbox;
+use Activitypub\Collection\Remote_Actors;
+
+/**
+ * Post Types class.
+ */
+class Post_Types {
+	/**
+	 * Initialize the class, registering all custom post types and post meta.
+	 */
+	public static function init() {
+		self::register_remote_actors_post_type();
+		self::register_inbox_post_type();
+		self::register_outbox_post_type();
+		self::register_extra_fields_post_types();
+		self::register_activitypub_post_meta();
+
+		\add_action( 'rest_api_init', array( self::class, 'register_ap_actor_rest_field' ) );
+
+		\add_filter( 'activitypub_get_actor_extra_fields', array( Extra_Fields::class, 'default_actor_extra_fields' ), 10, 2 );
+
+		\add_filter( 'add_post_metadata', array( self::class, 'prevent_empty_post_meta' ), 10, 4 );
+		\add_filter( 'update_post_metadata', array( self::class, 'prevent_empty_post_meta' ), 10, 4 );
+		\add_filter( 'default_post_metadata', array( self::class, 'default_post_meta_data' ), 10, 3 );
+
+		// Add support for ActivityPub to custom post types.
+		foreach ( \get_option( 'activitypub_support_post_types', array( 'post' ) ) as $post_type ) {
+			\add_post_type_support( $post_type, 'activitypub' );
+		}
+	}
+
+	/**
+	 * Register the Remote Actors post type and its meta.
+	 */
+	public static function register_remote_actors_post_type() {
+		\register_post_type(
+			Remote_Actors::POST_TYPE,
+			array(
+				'labels'           => array(
+					'name'          => \_x( 'Followers', 'post_type plural name', 'activitypub' ),
+					'singular_name' => \_x( 'Follower', 'post_type single name', 'activitypub' ),
+				),
+				'public'           => false,
+				'show_in_rest'     => true,
+				'hierarchical'     => false,
+				'rewrite'          => false,
+				'query_var'        => false,
+				'delete_with_user' => false,
+				'can_export'       => true,
+				'supports'         => array(),
+			)
+		);
+
+		// Register meta for Remote Actors post type.
+		\register_post_meta(
+			Remote_Actors::POST_TYPE,
+			'_activitypub_inbox',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'sanitize_callback' => 'sanitize_url',
+			)
+		);
+
+		\register_post_meta(
+			Remote_Actors::POST_TYPE,
+			'_activitypub_errors',
+			array(
+				'type'              => 'string',
+				'single'            => false,
+				'sanitize_callback' => 'sanitize_text_field',
+			)
+		);
+
+		\register_post_meta(
+			Remote_Actors::POST_TYPE,
+			Followers::FOLLOWER_META_KEY,
+			array(
+				'type'              => 'string',
+				'single'            => false,
+				'sanitize_callback' => 'sanitize_text_field',
+			)
+		);
+	}
+
+	/**
+	 * Register the Inbox post type and its meta.
+	 */
+	public static function register_inbox_post_type() {
+		\register_post_type(
+			Inbox::POST_TYPE,
+			array(
+				'labels'              => array(
+					'name'          => \_x( 'Inbox', 'post_type plural name', 'activitypub' ),
+					'singular_name' => \_x( 'Inbox Item', 'post_type single name', 'activitypub' ),
+				),
+				'capabilities'        => array(
+					'create_posts' => false,
+				),
+				'map_meta_cap'        => true,
+				'public'              => false,
+				'show_in_rest'        => true,
+				'rewrite'             => false,
+				'query_var'           => false,
+				'supports'            => array( 'title', 'editor', 'author', 'custom-fields' ),
+				'delete_with_user'    => true,
+				'can_export'          => true,
+				'exclude_from_search' => true,
+			)
+		);
+
+		// Register meta for Inbox post type.
+		\register_post_meta(
+			Inbox::POST_TYPE,
+			'_activitypub_object_id',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'description'       => 'The ID (ActivityPub URI) of the object that the inbox item is about.',
+				'sanitize_callback' => 'sanitize_url',
+			)
+		);
+
+		\register_post_meta(
+			Inbox::POST_TYPE,
+			'_activitypub_activity_type',
+			array(
+				'type'              => 'string',
+				'description'       => 'The type of the activity',
+				'single'            => true,
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$value  = ucfirst( strtolower( $value ) );
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => Activity::TYPES,
+						'default' => 'Create',
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+
+		\register_post_meta(
+			Inbox::POST_TYPE,
+			'_activitypub_activity_actor',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'description'       => 'The type of the local actor that received the activity.',
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => array( 'application', 'blog', 'user' ),
+						'default' => 'user',
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+
+		\register_post_meta(
+			Inbox::POST_TYPE,
+			'_activitypub_activity_remote_actor',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'description'       => 'The ID (ActivityPub URI) of the remote actor that sent the activity.',
+				'sanitize_callback' => 'sanitize_url',
+			)
+		);
+
+		\register_post_meta(
+			Inbox::POST_TYPE,
+			'activitypub_content_visibility',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => array( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL ),
+						'default' => ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+	}
+
+	/**
+	 * Register the Outbox post type and its meta.
+	 */
+	public static function register_outbox_post_type() {
+		\register_post_type(
+			Outbox::POST_TYPE,
+			array(
+				'labels'              => array(
+					'name'          => \_x( 'Outbox', 'post_type plural name', 'activitypub' ),
+					'singular_name' => \_x( 'Outbox Item', 'post_type single name', 'activitypub' ),
+				),
+				'capabilities'        => array(
+					'create_posts' => false,
+				),
+				'map_meta_cap'        => true,
+				'public'              => false,
+				'show_in_rest'        => true,
+				'rewrite'             => false,
+				'query_var'           => false,
+				'supports'            => array( 'title', 'editor', 'author', 'custom-fields' ),
+				'delete_with_user'    => true,
+				'can_export'          => true,
+				'exclude_from_search' => true,
+			)
+		);
+
+		// Register meta for Outbox post type.
+		/**
+		 * Register Activity Type meta for Outbox items.
+		 *
+		 * @see https://www.w3.org/TR/activitystreams-vocabulary/#activity-types
+		 */
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'_activitypub_activity_type',
+			array(
+				'type'              => 'string',
+				'description'       => 'The type of the activity',
+				'single'            => true,
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$value  = ucfirst( strtolower( $value ) );
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => Activity::TYPES,
+						'default' => 'Announce',
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'_activitypub_activity_actor',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => array( 'application', 'blog', 'user' ),
+						'default' => 'user',
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'_activitypub_outbox_offset',
+			array(
+				'type'              => 'integer',
+				'single'            => true,
+				'description'       => 'Keeps track of the followers offset when processing outbox items.',
+				'sanitize_callback' => 'absint',
+				'default'           => 0,
+			)
+		);
+
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'_activitypub_object_id',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'description'       => 'The ID (ActivityPub URI) of the object that the outbox item is about.',
+				'sanitize_callback' => 'sanitize_url',
+			)
+		);
+
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'activitypub_content_visibility',
+			array(
+				'type'              => 'string',
+				'single'            => true,
+				'show_in_rest'      => true,
+				'sanitize_callback' => function ( $value ) {
+					$schema = array(
+						'type'    => 'string',
+						'enum'    => array( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL ),
+						'default' => ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
+					);
+
+					if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+						return $schema['default'];
+					}
+
+					return $value;
+				},
+			)
+		);
+	}
+
+	/**
+	 * Register the Extra Fields post types.
+	 */
+	public static function register_extra_fields_post_types() {
+		$extra_field_args = array(
+			'labels'              => array(
+				'name'          => \_x( 'Extra fields', 'post_type plural name', 'activitypub' ),
+				'singular_name' => \_x( 'Extra field', 'post_type single name', 'activitypub' ),
+				'add_new'       => \__( 'Add new', 'activitypub' ),
+				'add_new_item'  => \__( 'Add new extra field', 'activitypub' ),
+				'new_item'      => \__( 'New extra field', 'activitypub' ),
+				'edit_item'     => \__( 'Edit extra field', 'activitypub' ),
+				'view_item'     => \__( 'View extra field', 'activitypub' ),
+				'all_items'     => \__( 'All extra fields', 'activitypub' ),
+			),
+			'public'              => false,
+			'hierarchical'        => false,
+			'query_var'           => false,
+			'has_archive'         => false,
+			'publicly_queryable'  => false,
+			'show_in_menu'        => false,
+			'delete_with_user'    => true,
+			'can_export'          => true,
+			'exclude_from_search' => true,
+			'show_in_rest'        => true,
+			'map_meta_cap'        => true,
+			'show_ui'             => true,
+			'supports'            => array( 'title', 'editor', 'page-attributes' ),
+		);
+
+		\register_post_type( Extra_Fields::USER_POST_TYPE, $extra_field_args );
+		\register_post_type( Extra_Fields::BLOG_POST_TYPE, $extra_field_args );
+
+		/**
+		 * Fires after ActivityPub custom post types have been registered.
+		 */
+		\do_action( 'activitypub_after_register_post_type' );
+	}
+
+	/**
+	 * Register post meta for ActivityPub supported post types.
+	 */
+	public static function register_activitypub_post_meta() {
+		$ap_post_types = \get_post_types_by_support( 'activitypub' );
+		foreach ( $ap_post_types as $post_type ) {
+			\register_post_meta(
+				$post_type,
+				'activitypub_content_warning',
+				array(
+					'show_in_rest'      => true,
+					'single'            => true,
+					'type'              => 'string',
+					'sanitize_callback' => 'sanitize_text_field',
+				)
+			);
+
+			\register_post_meta(
+				$post_type,
+				'activitypub_content_visibility',
+				array(
+					'type'              => 'string',
+					'single'            => true,
+					'show_in_rest'      => true,
+					'sanitize_callback' => function ( $value ) {
+						$schema = array(
+							'type'    => 'string',
+							'enum'    => array( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL ),
+							'default' => ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
+						);
+
+						if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+							return $schema['default'];
+						}
+
+						return $value;
+					},
+				)
+			);
+
+			\register_post_meta(
+				$post_type,
+				'activitypub_max_image_attachments',
+				array(
+					'type'              => 'integer',
+					'single'            => true,
+					'show_in_rest'      => true,
+					'default'           => \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ),
+					'sanitize_callback' => 'absint',
+				)
+			);
+
+			\register_post_meta(
+				$post_type,
+				'activitypub_interaction_policy_quote',
+				array(
+					'type'              => 'string',
+					'single'            => true,
+					'show_in_rest'      => true,
+					'sanitize_callback' => function ( $value ) {
+						$schema = array(
+							'type'    => 'string',
+							'enum'    => array( ACTIVITYPUB_INTERACTION_POLICY_ANYONE, ACTIVITYPUB_INTERACTION_POLICY_FOLLOWERS, ACTIVITYPUB_INTERACTION_POLICY_ME ),
+							'default' => ACTIVITYPUB_INTERACTION_POLICY_ANYONE,
+						);
+
+						if ( \is_wp_error( \rest_validate_enum( $value, $schema, '' ) ) ) {
+							return $schema['default'];
+						}
+
+						return $value;
+					},
+				)
+			);
+		}
+	}
+
+	/**
+	 * Register REST field for ap_actor posts.
+	 */
+	public static function register_ap_actor_rest_field() {
+		\register_rest_field(
+			Remote_Actors::POST_TYPE,
+			'activitypub_json',
+			array(
+				/**
+				 * Get the raw post content without WordPress content filtering.
+				 *
+				 * @param array $response Prepared response array.
+				 * @return string The raw post content.
+				 */
+				'get_callback' => function ( $response ) {
+					return \get_post_field( 'post_content', $response['id'] );
+				},
+				'schema'       => array(
+					'description' => 'Raw ActivityPub JSON data without WordPress content filtering',
+					'type'        => 'string',
+					'context'     => array( 'view', 'edit' ),
+				),
+			)
+		);
+	}
+
+	/**
+	 * Prevent empty or default meta values.
+	 *
+	 * @param null|bool $check      Whether to allow updating metadata for the given type.
+	 * @param int       $object_id  ID of the object metadata is for.
+	 * @param string    $meta_key   Metadata key.
+	 * @param mixed     $meta_value Metadata value. Must be serializable if non-scalar.
+	 */
+	public static function prevent_empty_post_meta( $check, $object_id, $meta_key, $meta_value ) {
+		$post_metas = array(
+			'activitypub_content_visibility'       => '',
+			'activitypub_content_warning'          => '',
+			'activitypub_interaction_policy_quote' => ACTIVITYPUB_INTERACTION_POLICY_ANYONE,
+			'activitypub_max_image_attachments'    => (string) \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ),
+		);
+
+		if ( isset( $post_metas[ $meta_key ] ) && $post_metas[ $meta_key ] === (string) $meta_value ) {
+			if ( 'update_post_metadata' === current_action() ) {
+				\delete_post_meta( $object_id, $meta_key );
+			}
+
+			$check = true;
+		}
+
+		return $check;
+	}
+
+	/**
+	 * Adjusts default post meta values.
+	 *
+	 * @param mixed  $meta_value The meta value.
+	 * @param int    $object_id  ID of the object metadata is for.
+	 * @param string $meta_key   Metadata key.
+	 *
+	 * @return string|null The meta value.
+	 */
+	public static function default_post_meta_data( $meta_value, $object_id, $meta_key ) {
+		if ( 'activitypub_content_visibility' !== $meta_key ) {
+			return $meta_value;
+		}
+
+		// If meta value is already explicitly set, respect the author's choice.
+		if ( null !== $meta_value ) {
+			return $meta_value;
+		}
+
+		// If the post is federated, return the default visibility.
+		if ( 'federated' === \get_post_meta( $object_id, 'activitypub_status', true ) ) {
+			return null;
+		}
+
+		// If the post is not federated and older than a month, return local visibility.
+		if ( \get_the_date( 'U', $object_id ) < \strtotime( '-1 month' ) ) {
+			return ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL;
+		}
+
+		return null;
+	}
+}
diff --git a/tests/includes/class-test-activitypub.php b/tests/includes/class-test-activitypub.php
index 15bc66498..7d13b6050 100644
--- a/tests/includes/class-test-activitypub.php
+++ b/tests/includes/class-test-activitypub.php
@@ -104,7 +104,7 @@ function () {
 	 * Test activity type meta sanitization.
 	 *
 	 * @dataProvider activity_meta_sanitization_provider
-	 * @covers ::register_post_types
+	 * @covers \Activitypub\Post_Types::register_outbox_post_type
 	 *
 	 * @param string $meta_key   Meta key.
 	 * @param mixed  $meta_value Meta value.
@@ -294,80 +294,4 @@ public function test_no_trailing_redirect() {
 		// Clean up.
 		set_query_var( 'actor', null );
 	}
-
-	/**
-	 * Test prevent_empty_post_meta method.
-	 *
-	 * @covers ::prevent_empty_post_meta
-	 */
-	public function test_prevent_empty_post_meta() {
-		$post_id = self::factory()->post->create(
-			array(
-				'post_author' => 1,
-			)
-		);
-
-		\update_post_meta( $post_id, 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS );
-		$this->assertEmpty( \get_post_meta( $post_id, 'activitypub_max_image_attachments', true ) );
-		\delete_post_meta( $post_id, 'activitypub_max_image_attachments' );
-
-		\update_post_meta( $post_id, 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS + 3 );
-		$this->assertEquals( ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS + 3, \get_post_meta( $post_id, 'activitypub_max_image_attachments', true ) );
-		\delete_post_meta( $post_id, 'activitypub_max_image_attachments' );
-
-		\wp_delete_post( $post_id, true );
-	}
-
-	/**
-	 * Test get_post_metadata method.
-	 *
-	 * @covers ::default_post_metadata
-	 */
-	public function test_get_post_metadata() {
-		// Create a test post.
-		$post_id = self::factory()->post->create(
-			array(
-				'post_author' => 1,
-				'post_date'   => gmdate( 'Y-m-d H:i:s', strtotime( '-2 months' ) ), // Post older than a month.
-			)
-		);
-
-		// Test 1: When meta_key is not 'activitypub_content_visibility', should return the original value.
-		$result = Activitypub::default_post_metadata( 'original_value', $post_id, 'some_other_key' );
-		$this->assertEquals( 'original_value', $result, 'Should return original value for non-matching meta key.' );
-
-		// Test 2: When post is federated, should return the original value.
-		\update_post_meta( $post_id, 'activitypub_status', 'federated' );
-		$result = Activitypub::default_post_metadata( 'original_value', $post_id, 'activitypub_content_visibility' );
-		$this->assertEquals( 'original_value', $result, 'Should return original value for federated posts.' );
-
-		// Test 3: When post is not federated and older than a month, should return local visibility.
-		\update_post_meta( $post_id, 'activitypub_status', 'pending' );
-		$result = Activitypub::default_post_metadata( null, $post_id, 'activitypub_content_visibility' );
-		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL, $result, 'Should return local visibility for old non-federated posts.' );
-
-		// Test 4: When post is not federated but less than a month old, should return original value.
-		$recent_post_id = self::factory()->post->create(
-			array(
-				'post_author' => 1,
-				'post_date'   => gmdate( 'Y-m-d H:i:s', strtotime( '-2 weeks' ) ), // Recent post.
-			)
-		);
-		\update_post_meta( $recent_post_id, 'activitypub_status', 'pending' );
-		$result = Activitypub::default_post_metadata( null, $recent_post_id, 'activitypub_content_visibility' );
-		$this->assertEquals( null, $result, 'Should return original value for recent non-federated posts.' );
-
-		// Test 5: When meta value is already set (not null), should respect author's explicit choice.
-		\update_post_meta( $post_id, 'activitypub_status', 'pending' ); // Ensure not federated.
-		$result = Activitypub::default_post_metadata( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, $post_id, 'activitypub_content_visibility' );
-		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, $result, 'Should respect explicitly set public visibility even for old unfederated posts.' );
-
-		// Test 6: Only apply local visibility when meta value is null (no explicit setting).
-		$result = Activitypub::default_post_metadata( null, $post_id, 'activitypub_content_visibility' );
-		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL, $result, 'Should return local visibility when no explicit value is set for old unfederated posts.' );
-
-		// Clean up.
-		\wp_delete_post( $post_id, true );
-		\wp_delete_post( $recent_post_id, true );
-	}
 }
diff --git a/tests/includes/class-test-blocks.php b/tests/includes/class-test-blocks.php
index c2707db2d..783b1f0c9 100644
--- a/tests/includes/class-test-blocks.php
+++ b/tests/includes/class-test-blocks.php
@@ -19,7 +19,7 @@ class Test_Blocks extends \WP_UnitTestCase {
 	/**
 	 * Test register_post_meta.
 	 *
-	 * @covers ::register_postmeta
+	 * @covers \Activitypub\Post_Types::register_activitypub_post_meta
 	 */
 	public function test_register_post_meta() {
 		// Empty option should not trigger _doing_it_wrong() notice.
diff --git a/tests/includes/class-test-post-types.php b/tests/includes/class-test-post-types.php
new file mode 100644
index 000000000..099c94655
--- /dev/null
+++ b/tests/includes/class-test-post-types.php
@@ -0,0 +1,99 @@
+<?php
+/**
+ * Test file for Post Types.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub\Tests;
+
+use Activitypub\Activitypub;
+use Activitypub\Post_Types;
+
+/**
+ * Test class for Post Types.
+ *
+ * @coversDefaultClass \Activitypub\Post_Types
+ */
+class Test_Post_Types extends \WP_UnitTestCase {
+
+	/**
+	 * Set up test environment.
+	 */
+	public function setUp(): void {
+		parent::setUp();
+		Activitypub::init();
+	}
+
+	/**
+	 * Test prevent_empty_post_meta method.
+	 *
+	 * @covers ::prevent_empty_post_meta
+	 */
+	public function test_prevent_empty_post_meta() {
+		$post_id = self::factory()->post->create( array( 'post_author' => 1 ) );
+
+		\update_post_meta( $post_id, 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS );
+		$this->assertEmpty( \get_post_meta( $post_id, 'activitypub_max_image_attachments', true ) );
+		\delete_post_meta( $post_id, 'activitypub_max_image_attachments' );
+
+		\update_post_meta( $post_id, 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS + 3 );
+		$this->assertEquals( ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS + 3, \get_post_meta( $post_id, 'activitypub_max_image_attachments', true ) );
+		\delete_post_meta( $post_id, 'activitypub_max_image_attachments' );
+
+		\wp_delete_post( $post_id, true );
+	}
+
+	/**
+	 * Test get_post_metadata method.
+	 *
+	 * @covers ::default_post_meta_data
+	 */
+	public function test_get_post_metadata() {
+		// Create a test post.
+		$post_id = self::factory()->post->create(
+			array(
+				'post_author' => 1,
+				'post_date'   => gmdate( 'Y-m-d H:i:s', strtotime( '-2 months' ) ), // Post older than a month.
+			)
+		);
+
+		// Test 1: When meta_key is not 'activitypub_content_visibility', should return the original value.
+		$result = Post_Types::default_post_meta_data( 'original_value', $post_id, 'some_other_key' );
+		$this->assertEquals( 'original_value', $result, 'Should return original value for non-matching meta key.' );
+
+		// Test 2: When post is federated, should return the original value.
+		\update_post_meta( $post_id, 'activitypub_status', 'federated' );
+		$result = Post_Types::default_post_meta_data( 'original_value', $post_id, 'activitypub_content_visibility' );
+		$this->assertEquals( 'original_value', $result, 'Should return original value for federated posts.' );
+
+		// Test 3: When post is not federated and older than a month, should return local visibility.
+		\update_post_meta( $post_id, 'activitypub_status', 'pending' );
+		$result = Post_Types::default_post_meta_data( null, $post_id, 'activitypub_content_visibility' );
+		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL, $result, 'Should return local visibility for old non-federated posts.' );
+
+		// Test 4: When post is not federated but less than a month old, should return original value.
+		$recent_post_id = self::factory()->post->create(
+			array(
+				'post_author' => 1,
+				'post_date'   => gmdate( 'Y-m-d H:i:s', strtotime( '-2 weeks' ) ), // Recent post.
+			)
+		);
+		\update_post_meta( $recent_post_id, 'activitypub_status', 'pending' );
+		$result = Post_Types::default_post_meta_data( null, $recent_post_id, 'activitypub_content_visibility' );
+		$this->assertEquals( null, $result, 'Should return original value for recent non-federated posts.' );
+
+		// Test 5: When meta value is already set (not null), should respect author's explicit choice.
+		\update_post_meta( $post_id, 'activitypub_status', 'pending' ); // Ensure not federated.
+		$result = Post_Types::default_post_meta_data( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, $post_id, 'activitypub_content_visibility' );
+		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC, $result, 'Should respect explicitly set public visibility even for old unfederated posts.' );
+
+		// Test 6: Only apply local visibility when meta value is null (no explicit setting).
+		$result = Post_Types::default_post_meta_data( null, $post_id, 'activitypub_content_visibility' );
+		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL, $result, 'Should return local visibility when no explicit value is set for old unfederated posts.' );
+
+		// Clean up.
+		\wp_delete_post( $post_id, true );
+		\wp_delete_post( $recent_post_id, true );
+	}
+}
diff --git a/tests/includes/collection/class-test-inbox.php b/tests/includes/collection/class-test-inbox.php
index 20f27379d..32e8898f0 100644
--- a/tests/includes/collection/class-test-inbox.php
+++ b/tests/includes/collection/class-test-inbox.php
@@ -9,8 +9,8 @@
 
 use Activitypub\Activity\Activity;
 use Activitypub\Activity\Base_Object;
-use Activitypub\Activitypub;
 use Activitypub\Collection\Inbox;
+use Activitypub\Post_Types;
 
 /**
  * Test class for Inbox collection.
@@ -214,7 +214,7 @@ public function test_duplicate_activity_prevention() {
 	 * Test post meta registration exists.
 	 */
 	public function test_post_meta_registration() {
-		Activitypub::register_post_types();
+		Post_Types::register_inbox_post_type();
 
 		// Verify that post meta is registered for inbox post type.
 		$registered_meta = \get_registered_meta_keys( 'post', Inbox::POST_TYPE );