diff --git a/activitypub.php b/activitypub.php
index c812cc49f..22a23ec49 100644
--- a/activitypub.php
+++ b/activitypub.php
@@ -47,8 +47,8 @@ function rest_init() {
 	Rest\Comment::init();
 	Rest\Server::init();
 	Rest\Collection::init();
-	Rest\Interaction::init();
 	Rest\Post::init();
+	( new Rest\Interaction_Controller() )->register_routes();
 	( new Rest\Application_Controller() )->register_routes();
 	( new Rest\Webfinger_Controller() )->register_routes();
 
diff --git a/includes/collection/class-followers.php b/includes/collection/class-followers.php
index d6f8b0727..77ade14e1 100644
--- a/includes/collection/class-followers.php
+++ b/includes/collection/class-followers.php
@@ -98,7 +98,7 @@ public static function remove_follower( $user_id, $actor ) {
 	 * @param int    $user_id The ID of the WordPress User.
 	 * @param string $actor   The Actor URL.
 	 *
-	 * @return Follower|null The Follower object or null
+	 * @return \Activitypub\Activity\Base_Object|WP_Error|null The Follower object or null
 	 */
 	public static function get_follower( $user_id, $actor ) {
 		global $wpdb;
@@ -266,7 +266,7 @@ public static function count_followers( $user_id ) {
 	}
 
 	/**
-	 * Returns all Inboxes for a Users Followers.
+	 * Returns all Inboxes for an Actor's Followers.
 	 *
 	 * @param int $user_id The ID of the WordPress User.
 	 *
diff --git a/includes/handler/class-update.php b/includes/handler/class-update.php
index 983c68d42..e09eeb85a 100644
--- a/includes/handler/class-update.php
+++ b/includes/handler/class-update.php
@@ -26,9 +26,9 @@ public static function init() {
 	}
 
 	/**
-	 * Handle "Update" requests
+	 * Handle "Update" requests.
 	 *
-	 * @param array $activity The activity-object.
+	 * @param array $activity The Activity object.
 	 */
 	public static function handle_update( $activity ) {
 		$object_type = isset( $activity['object']['type'] ) ? $activity['object']['type'] : '';
@@ -75,7 +75,7 @@ public static function handle_update( $activity ) {
 	/**
 	 * Update an Interaction.
 	 *
-	 * @param array $activity The activity-object.
+	 * @param array $activity The Activity object.
 	 */
 	public static function update_interaction( $activity ) {
 		$commentdata = Interactions::update_comment( $activity );
@@ -102,7 +102,7 @@ public static function update_interaction( $activity ) {
 	/**
 	 * Update an Actor.
 	 *
-	 * @param array $activity The activity-object.
+	 * @param array $activity The Activity object.
 	 */
 	public static function update_actor( $activity ) {
 		// Update cache.
diff --git a/includes/rest/class-interaction.php b/includes/rest/class-interaction-controller.php
similarity index 53%
rename from includes/rest/class-interaction.php
rename to includes/rest/class-interaction-controller.php
index 2eca4bf2e..f9620e3a4 100644
--- a/includes/rest/class-interaction.php
+++ b/includes/rest/class-interaction-controller.php
@@ -1,43 +1,50 @@
 <?php
 /**
- * ActivityPub Interaction REST-Class file.
+ * ActivityPub Interaction Controller file.
  *
  * @package Activitypub
  */
 
 namespace Activitypub\Rest;
 
-use WP_REST_Response;
 use Activitypub\Http;
 
 /**
- * Interaction class.
+ * Interaction Controller.
  */
-class Interaction {
+class Interaction_Controller extends \WP_REST_Controller {
 	/**
-	 * Initialize the class, registering WordPress hooks.
+	 * The namespace of this controller's route.
+	 *
+	 * @var string
 	 */
-	public static function init() {
-		self::register_routes();
-	}
+	protected $namespace = ACTIVITYPUB_REST_NAMESPACE;
 
 	/**
-	 * Register routes
+	 * The base of this controller's route.
+	 *
+	 * @var string
 	 */
-	public static function register_routes() {
+	protected $rest_base = 'interactions';
+
+	/**
+	 * Register routes.
+	 */
+	public function register_routes() {
 		\register_rest_route(
-			ACTIVITYPUB_REST_NAMESPACE,
-			'/interactions',
+			$this->namespace,
+			'/' . $this->rest_base,
 			array(
 				array(
 					'methods'             => \WP_REST_Server::READABLE,
-					'callback'            => array( self::class, 'get' ),
+					'callback'            => array( $this, 'get_item' ),
 					'permission_callback' => '__return_true',
 					'args'                => array(
 						'uri' => array(
-							'type'              => 'string',
-							'required'          => true,
-							'sanitize_callback' => 'esc_url',
+							'description' => 'The URI of the object to interact with.',
+							'type'        => 'string',
+							'format'      => 'uri',
+							'required'    => true,
 						),
 					),
 				),
@@ -46,27 +53,26 @@ public static function register_routes() {
 	}
 
 	/**
-	 * Handle GET request.
+	 * Retrieves the interaction URL for a given URI.
 	 *
 	 * @param \WP_REST_Request $request The request object.
 	 *
-	 * @return WP_REST_Response Redirect to the editor or die.
+	 * @return \WP_REST_Response Response object on success, dies on failure.
 	 */
-	public static function get( $request ) {
+	public function get_item( $request ) {
 		$uri          = $request->get_param( 'uri' );
 		$redirect_url = null;
 		$object       = Http::get_remote_object( $uri );
 
-		if (
-			\is_wp_error( $object ) ||
-			! isset( $object['type'] )
-		) {
+		if ( \is_wp_error( $object ) || ! isset( $object['type'] ) ) {
+			// Use wp_die as this can be called from the front-end. See https://github.com/Automattic/wordpress-activitypub/pull/1149/files#r1915297109.
 			\wp_die(
-				\esc_html__(
-					'The URL is not supported!',
-					'activitypub'
-				),
-				400
+				esc_html__( 'The URL is not supported!', 'activitypub' ),
+				'',
+				array(
+					'response'  => 400,
+					'back_link' => true,
+				)
 			);
 		}
 
@@ -104,31 +110,30 @@ public static function get( $request ) {
 		}
 
 		/**
-		 * Filter the redirect URL.
+		 * Filters the redirect URL.
+		 *
+		 * This filter runs after the type-specific filters and allows for final modifications
+		 * to the interaction URL regardless of the object type.
 		 *
 		 * @param string $redirect_url The URL to redirect to.
 		 * @param string $uri          The URI of the object.
-		 * @param array  $object       The object.
+		 * @param array  $object       The object being interacted with.
 		 */
 		$redirect_url = \apply_filters( 'activitypub_interactions_url', $redirect_url, $uri, $object );
 
 		// Check if hook is implemented.
 		if ( ! $redirect_url ) {
+			// Use wp_die as this can be called from the front-end. See https://github.com/Automattic/wordpress-activitypub/pull/1149/files#r1915297109.
 			\wp_die(
-				esc_html__(
-					'This Interaction type is not supported yet!',
-					'activitypub'
-				),
-				400
+				esc_html__( 'This Interaction type is not supported yet!', 'activitypub' ),
+				'',
+				array(
+					'response'  => 400,
+					'back_link' => true,
+				)
 			);
 		}
 
-		return new WP_REST_Response(
-			null,
-			302,
-			array(
-				'Location' => \esc_url( $redirect_url ),
-			)
-		);
+		return new \WP_REST_Response( null, 302, array( 'Location' => \esc_url( $redirect_url ) ) );
 	}
 }
diff --git a/tests/includes/class-test-activity-dispatcher.php b/tests/includes/class-test-activity-dispatcher.php
index 1ecda7971..09a3628b3 100644
--- a/tests/includes/class-test-activity-dispatcher.php
+++ b/tests/includes/class-test-activity-dispatcher.php
@@ -17,11 +17,11 @@
 class Test_Activity_Dispatcher extends ActivityPub_TestCase_Cache_HTTP {
 
 	/**
-	 * Users.
+	 * Actors.
 	 *
-	 * @var array[] $users
+	 * @var array[]
 	 */
-	public static $users = array(
+	public static $actors = array(
 		'username@example.org' => array(
 			'id'                => 'https://example.org/users/username',
 			'url'               => 'https://example.org/users/username',
@@ -109,7 +109,7 @@ public function test_dispatch_mentions() {
 			)
 		);
 
-		self::$users['https://example.com/alex'] = array(
+		self::$actors['https://example.com/alex'] = array(
 			'id'    => 'https://example.com/alex',
 			'url'   => 'https://example.com/alex',
 			'inbox' => 'https://example.com/alex/inbox',
@@ -300,10 +300,10 @@ function ( $disabled, $user_id ) {
 	 * @return array|bool
 	 */
 	public static function pre_get_remote_metadata_by_actor( $pre, $actor ) {
-		if ( isset( self::$users[ $actor ] ) ) {
-			return self::$users[ $actor ];
+		if ( isset( self::$actors[ $actor ] ) ) {
+			return self::$actors[ $actor ];
 		}
-		foreach ( self::$users as $data ) {
+		foreach ( self::$actors as $data ) {
 			if ( $data['url'] === $actor ) {
 				return $data;
 			}
diff --git a/tests/includes/class-test-mention.php b/tests/includes/class-test-mention.php
index 65917a22d..badc7d635 100644
--- a/tests/includes/class-test-mention.php
+++ b/tests/includes/class-test-mention.php
@@ -17,11 +17,11 @@
 class Test_Mention extends \WP_UnitTestCase {
 
 	/**
-	 * Users.
+	 * Actors.
 	 *
-	 * @var array
+	 * @var array[]
 	 */
-	public static $users = array(
+	public static $actors = array(
 		'username@example.org' => array(
 			'id'   => 'https://example.org/users/username',
 			'url'  => 'https://example.org/users/username',
@@ -133,8 +133,8 @@ public function pre_http_request( $response, $parsed_args, $url ) {
 	public static function pre_get_remote_metadata_by_actor( $pre, $actor ) {
 		$actor = ltrim( $actor, '@' );
 
-		if ( isset( self::$users[ $actor ] ) ) {
-			return self::$users[ $actor ];
+		if ( isset( self::$actors[ $actor ] ) ) {
+			return self::$actors[ $actor ];
 		}
 
 		return $pre;
diff --git a/tests/includes/collection/class-test-followers.php b/tests/includes/collection/class-test-followers.php
index 4eab7196b..c2cd8656f 100644
--- a/tests/includes/collection/class-test-followers.php
+++ b/tests/includes/collection/class-test-followers.php
@@ -17,11 +17,11 @@
 class Test_Followers extends \WP_UnitTestCase {
 
 	/**
-	 * Users.
+	 * Actors.
 	 *
 	 * @var array[]
 	 */
-	public static $users = array(
+	public static $actors = array(
 		'username@example.org' => array(
 			'id'                => 'https://example.org/users/username',
 			'url'               => 'https://example.org/users/username',
@@ -399,8 +399,8 @@ public function test_migration_followers( $followers, $expected_count ) {
 		add_filter(
 			'pre_get_remote_metadata_by_actor',
 			function ( $pre, $actor ) {
-				if ( isset( self::$users[ $actor ] ) ) {
-					return self::$users[ $actor ];
+				if ( isset( self::$actors[ $actor ] ) ) {
+					return self::$actors[ $actor ];
 				}
 				return $pre;
 			},
@@ -549,10 +549,10 @@ public function test_get_all_followers() {
 	 * @return array
 	 */
 	public static function pre_get_remote_metadata_by_actor( $pre, $actor ) {
-		if ( isset( self::$users[ $actor ] ) ) {
-			return self::$users[ $actor ];
+		if ( isset( self::$actors[ $actor ] ) ) {
+			return self::$actors[ $actor ];
 		}
-		foreach ( self::$users as $data ) {
+		foreach ( self::$actors as $data ) {
 			if ( $data['url'] === $actor ) {
 				return $data;
 			}
diff --git a/tests/includes/rest/class-test-interaction-controller.php b/tests/includes/rest/class-test-interaction-controller.php
new file mode 100644
index 000000000..e7cde7ac7
--- /dev/null
+++ b/tests/includes/rest/class-test-interaction-controller.php
@@ -0,0 +1,220 @@
+<?php
+/**
+ * Interaction REST API endpoint test file.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub\Tests\Rest;
+
+/**
+ * Tests for Interaction REST API endpoint.
+ *
+ * @coversDefaultClass \Activitypub\Rest\Interaction_Controller
+ */
+class Test_Interaction_Controller extends \Activitypub\Tests\Test_REST_Controller_Testcase {
+
+	/**
+	 * Tear down.
+	 */
+	public function tear_down() {
+		\remove_all_filters( 'activitypub_interactions_follow_url' );
+		\remove_all_filters( 'activitypub_interactions_reply_url' );
+
+		parent::tear_down();
+	}
+
+	/**
+	 * Test route registration.
+	 *
+	 * @covers ::register_routes
+	 */
+	public function test_register_routes() {
+		$routes = rest_get_server()->get_routes();
+		$this->assertArrayHasKey( '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions', $routes );
+	}
+
+	/**
+	 * Test get_item with invalid URI.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item_invalid_uri() {
+		$this->expectException( \WPDieException::class );
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'invalid-uri' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 400, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( 'activitypub_invalid_object', $data['code'] );
+	}
+
+	/**
+	 * Test get_item with Note object type.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item() {
+		\add_filter(
+			'pre_http_request',
+			function () {
+				return array(
+					'response' => array( 'code' => 200 ),
+					'body'     => wp_json_encode(
+						array(
+							'type' => 'Note',
+							'url'  => 'https://example.org/note',
+						)
+					),
+				);
+			}
+		);
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'https://example.org/note' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 302, $response->get_status() );
+		$this->assertArrayHasKey( 'Location', $response->get_headers() );
+		$this->assertStringContainsString( 'post-new.php?in_reply_to=', $response->get_headers()['Location'] );
+	}
+
+	/**
+	 * Test get_item with custom follow URL filter.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item_custom_follow_url() {
+		\add_filter(
+			'pre_http_request',
+			function () {
+				return array(
+					'response' => array( 'code' => 200 ),
+					'body'     => wp_json_encode(
+						array(
+							'type' => 'Person',
+							'url'  => 'https://example.org/person',
+						)
+					),
+				);
+			}
+		);
+
+		\add_filter( 'activitypub_interactions_follow_url', array( $this, 'follow_or_reply_url' ) );
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'https://example.org/person' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 302, $response->get_status() );
+		$this->assertArrayHasKey( 'Location', $response->get_headers() );
+		$this->assertEquals( 'https://custom-follow-or-reply-url.com', $response->get_headers()['Location'] );
+	}
+
+	/**
+	 * Test get_item with custom reply URL filter.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item_custom_reply_url() {
+		\add_filter(
+			'pre_http_request',
+			function () {
+				return array(
+					'response' => array( 'code' => 200 ),
+					'body'     => wp_json_encode(
+						array(
+							'type' => 'Note',
+							'url'  => 'https://example.org/note',
+						)
+					),
+				);
+			}
+		);
+
+		\add_filter( 'activitypub_interactions_reply_url', array( $this, 'follow_or_reply_url' ) );
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'https://example.org/note' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 302, $response->get_status() );
+		$this->assertArrayHasKey( 'Location', $response->get_headers() );
+		$this->assertEquals( 'https://custom-follow-or-reply-url.com', $response->get_headers()['Location'] );
+	}
+
+	/**
+	 * Test get_item with WP_Error response from get_remote_object.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item_wp_error() {
+		$this->expectException( \WPDieException::class );
+
+		\add_filter(
+			'pre_http_request',
+			function () {
+				return new \WP_Error( 'http_request_failed', 'Connection failed.' );
+			}
+		);
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'https://example.org/person' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 400, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( 'activitypub_invalid_object', $data['code'] );
+		$this->assertEquals( 'The URL is not supported!', $data['message'] );
+	}
+
+	/**
+	 * Test get_item with invalid object without type.
+	 *
+	 * @covers ::get_item
+	 */
+	public function test_get_item_invalid_object() {
+		$this->expectException( \WPDieException::class );
+
+		\add_filter(
+			'pre_http_request',
+			function () {
+				return array(
+					'response' => array( 'code' => 200 ),
+					'body'     => wp_json_encode(
+						array(
+							'url' => 'https://example.org/invalid',
+						)
+					),
+				);
+			}
+		);
+
+		$request = new \WP_REST_Request( 'GET', '/' . ACTIVITYPUB_REST_NAMESPACE . '/interactions' );
+		$request->set_param( 'uri', 'https://example.org/invalid' );
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertEquals( 400, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( 'activitypub_invalid_object', $data['code'] );
+		$this->assertEquals( 'The URL is not supported!', $data['message'] );
+	}
+
+	/**
+	 * Test get_item_schema method.
+	 *
+	 * @doesNotPerformAssertions
+	 */
+	public function test_get_item_schema() {
+		// Controller does not implement get_item_schema().
+	}
+
+	/**
+	 * Returns a valid follow URL.
+	 */
+	public function follow_or_reply_url() {
+		return 'https://custom-follow-or-reply-url.com';
+	}
+}