diff --git a/src/user_engine/adapters/delivery.py b/src/user_engine/adapters/delivery.py
index 5e9f2ab..2968b4b 100644
--- a/src/user_engine/adapters/delivery.py
+++ b/src/user_engine/adapters/delivery.py
@@ -39,7 +39,13 @@ class HTTPOutboxDeliveryAdapter:
         }
         if self.mail_url and event.event_type in _MAIL_EVENTS:
             self._post(self.mail_url, envelope)
-        self._post(self.event_url, envelope)
+        event_envelope = dict(envelope)
+        event_data = dict(envelope["data"])
+        if "primary_email" in event_data:
+            event_data["recipient_present"] = True
+            del event_data["primary_email"]
+        event_envelope["data"] = event_data
+        self._post(self.event_url, event_envelope)
 
     def _post(self, url: str, envelope: dict[str, object]) -> None:
         with urlopen(
diff --git a/src/user_engine/service.py b/src/user_engine/service.py
index 87cb32d..ae7ff82 100644
--- a/src/user_engine/service.py
+++ b/src/user_engine/service.py
@@ -2516,6 +2516,7 @@ class UserEngineService:
                     "family_scope_id": family_scope_id,
                     "application_id": application_id,
                     "role": role,
+                    "primary_email": invitation.primary_email,
                 },
                 application_id=application_id,
             )
@@ -2574,6 +2575,7 @@ class UserEngineService:
                     "invitation_id": updated.invitation_id,
                     "user_id": updated.user_id,
                     "resend_count": updated.resend_count,
+                    "primary_email": updated.primary_email,
                 },
                 application_id=updated.application_id,
             )
diff --git a/tests/test_platform_adapters.py b/tests/test_platform_adapters.py
index 1f064c0..6b6710b 100644
--- a/tests/test_platform_adapters.py
+++ b/tests/test_platform_adapters.py
@@ -53,6 +53,11 @@ class PlatformAdapterTests(unittest.TestCase):
                          ["http://mail", "http://events"])
         for item in call.call_args_list:
             self.assertEqual(item.args[0].get_header("Idempotency-key"), "evt-1")
+        mail_payload = json.loads(call.call_args_list[0].args[0].data)
+        event_payload = json.loads(call.call_args_list[1].args[0].data)
+        self.assertEqual(mail_payload["data"]["primary_email"], "person@example.test")
+        self.assertNotIn("primary_email", event_payload["data"])
+        self.assertTrue(event_payload["data"]["recipient_present"])
 
     def test_non_mail_event_only_calls_event_lane(self):
         adapter = HTTPOutboxDeliveryAdapter(