diff --git a/includes/model/class-activity.php b/includes/model/class-activity.php
index 32dd0f5..4bd0d5e 100644
--- a/includes/model/class-activity.php
+++ b/includes/model/class-activity.php
@@ -1,6 +1,8 @@
 <?php
 namespace Activitypub\Model;
 
+use function Activitypub\get_rest_url_by_path;
+
 /**
  * ActivityPub Post Class
  *
diff --git a/includes/model/class-post.php b/includes/model/class-post.php
index 528182c..5d189d9 100644
--- a/includes/model/class-post.php
+++ b/includes/model/class-post.php
@@ -1,6 +1,8 @@
 <?php
 namespace Activitypub\Model;
 
+use function Activitypub\get_rest_url_by_path;
+
 /**
  * ActivityPub Post Class
  *
diff --git a/includes/rest/class-followers.php b/includes/rest/class-followers.php
index 1ec2c78..145e57a 100644
--- a/includes/rest/class-followers.php
+++ b/includes/rest/class-followers.php
@@ -6,6 +6,7 @@ use stdClass;
 use WP_REST_Server;
 use WP_REST_Response;
 use Activitypub\Collection\Followers as FollowerCollection;
+use function Activitypub\get_rest_url_by_path;
 
 /**
  * ActivityPub Followers REST-Class
diff --git a/includes/rest/class-following.php b/includes/rest/class-following.php
index 0c685d5..93ad6a7 100644
--- a/includes/rest/class-following.php
+++ b/includes/rest/class-following.php
@@ -1,6 +1,8 @@
 <?php
 namespace Activitypub\Rest;
 
+use function Activitypub\get_rest_url_by_path;
+
 /**
  * ActivityPub Following REST-Class
  *
diff --git a/includes/rest/class-inbox.php b/includes/rest/class-inbox.php
index a73a783..7e2da60 100644
--- a/includes/rest/class-inbox.php
+++ b/includes/rest/class-inbox.php
@@ -2,6 +2,7 @@
 namespace Activitypub\Rest;
 
 use Activitypub\Model\Activity;
+use function Activitypub\get_rest_url_by_path;
 
 /**
  * ActivityPub Inbox REST-Class
diff --git a/includes/rest/class-nodeinfo.php b/includes/rest/class-nodeinfo.php
index 3b3c6dc..1d9de67 100644
--- a/includes/rest/class-nodeinfo.php
+++ b/includes/rest/class-nodeinfo.php
@@ -1,6 +1,8 @@
 <?php
 namespace Activitypub\Rest;
 
+use function Activitypub\get_rest_url_by_path;
+
 /**
  * ActivityPub NodeInfo REST-Class
  *
diff --git a/includes/rest/class-outbox.php b/includes/rest/class-outbox.php
index 1a52750..abffbe9 100644
--- a/includes/rest/class-outbox.php
+++ b/includes/rest/class-outbox.php
@@ -1,6 +1,8 @@
 <?php
 namespace Activitypub\Rest;
 
+use function Activitypub\get_rest_url_by_path;
+
 /**
  * ActivityPub Outbox REST-Class
  *
diff --git a/templates/author-json.php b/templates/author-json.php
index cf4b85e..f132b4b 100644
--- a/templates/author-json.php
+++ b/templates/author-json.php
@@ -1,4 +1,6 @@
 <?php
+use function Activitypub\get_rest_url_by_path;
+
 $author_id = \get_the_author_meta( 'ID' );
 
 $json = new \stdClass();
diff --git a/templates/blog-json.php b/templates/blog-json.php
index a988385..2da9c65 100644
--- a/templates/blog-json.php
+++ b/templates/blog-json.php
@@ -1,4 +1,6 @@
 <?php
+use function Activitypub\get_rest_url_by_path;
+
 $json = new \stdClass();
 
 $json->{'@context'} = \Activitypub\get_context();
diff --git a/tests/test-class-activitypub-activity.php b/tests/test-class-activitypub-activity.php
index 6569652..af0ed55 100644
--- a/tests/test-class-activitypub-activity.php
+++ b/tests/test-class-activitypub-activity.php
@@ -22,7 +22,7 @@ class Test_Activitypub_Activity extends WP_UnitTestCase {
 		$activitypub_activity = new \Activitypub\Model\Activity( 'Create' );
 		$activitypub_activity->from_post( $activitypub_post );
 
-		$this->assertContains(  get_rest_url_by_path( 'users/1/followers' ), $activitypub_activity->get_to() );
+		$this->assertContains(  \Activitypub\get_rest_url_by_path( 'users/1/followers' ), $activitypub_activity->get_to() );
 		$this->assertContains( 'https://example.com/alex', $activitypub_activity->get_cc() );
 
 		remove_all_filters( 'activitypub_extract_mentions' );