diff --git a/includes/functions.php b/includes/functions.php
index 39ba262..7d6f86c 100644
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -238,8 +238,11 @@ function is_tombstone( $wp_error ) {
 function get_rest_url_by_path( $path = '' ) {
 	// we'll handle the leading slash.
 	$path = ltrim( $path, '/' );
-	$url = sprintf( '/%s/%s', ACTIVITYPUB_REST_NAMESPACE, $path );
-	return \get_rest_url( null, $url );
+	$namespaced_path = sprintf( '/%s/%s', ACTIVITYPUB_REST_NAMESPACE, $path );
+	$rest_url = \get_rest_url( null, $namespaced_path );
+	// Just in case there are non-default ways of handling REST URLs.
+	$rest_url = \apply_filters( 'activitypub_rest_url', $rest_url, $path, ACTIVITYPUB_REST_NAMESPACE );
+	return $rest_url;
 }
 
 /**