diff --git a/authentik/core/tests/test_applications_api.py b/authentik/core/tests/test_applications_api.py
index 5c485ea68..587e3a3d2 100644
--- a/authentik/core/tests/test_applications_api.py
+++ b/authentik/core/tests/test_applications_api.py
@@ -43,14 +43,14 @@ class TestApplicationsAPI(APITestCase):
         self.assertEqual(
             self.client.patch(
                 reverse("authentik_api:application-detail", kwargs={"slug": self.allowed.slug}),
-                {"meta_launch_url": "https://%(username)s.test.goauthentik.io/%(username)s"},
+                {"meta_launch_url": "https://%(username)s-test.test.goauthentik.io/%(username)s"},
             ).status_code,
             200,
         )
         self.allowed.refresh_from_db()
         self.assertEqual(
             self.allowed.get_launch_url(self.user),
-            f"https://{self.user.username}.test.goauthentik.io/{self.user.username}",
+            f"https://{self.user.username}-test.test.goauthentik.io/{self.user.username}",
         )
 
     def test_set_icon(self):
diff --git a/authentik/lib/models.py b/authentik/lib/models.py
index 24054d9e2..19029c57f 100644
--- a/authentik/lib/models.py
+++ b/authentik/lib/models.py
@@ -81,7 +81,8 @@ class DomainlessFormattedURLValidator(DomainlessURLValidator):
 
     def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
-        self.host_re = r"([%\(\)a-zA-Z])+" + self.domain_re + self.domain_re
+        self.formatter_re = r"([%\(\)a-zA-Z])*"
+        self.host_re = "(" + self.formatter_re + self.hostname_re + self.domain_re + "|localhost)"
         self.regex = _lazy_re_compile(
             r"^(?:[a-z0-9.+-]*)://"  # scheme is validated separately
             r"(?:[^\s:@/]+(?::[^\s:@/]*)?@)?"  # user:pass authentication