diff --git a/libervia/backend/core/core_types.py b/libervia/backend/core/core_types.py
index 4f5a3e40..7d6c147a 100644
--- a/libervia/backend/core/core_types.py
+++ b/libervia/backend/core/core_types.py
@@ -286,7 +286,6 @@ class SatXMPPEntity(ABC):
         subject=None,
         mess_type="auto",
         extra=None,
-        uid=None,
         no_trigger=False,
     ):
         """Send a message to an entity
diff --git a/libervia/backend/core/main.py b/libervia/backend/core/main.py
index 4ed8007c..f5ac4ea0 100644
--- a/libervia/backend/core/main.py
+++ b/libervia/backend/core/main.py
@@ -1223,7 +1223,7 @@ class LiberviaBackend(service.Service):
         mess_type="auto",
         extra_s="",
         profile_key=C.PROF_KEY_NONE,
-    ):
+    ) -> defer.Deferred[None]:
         client = self.get_client(profile_key)
         to_jid = jid.JID(to_jid_s)
         d = client.sendMessage(
@@ -1231,7 +1231,7 @@ class LiberviaBackend(service.Service):
         )
         # sendMessage returns message data, but we must return nothing.
         d.addCallback(lambda __: None)
-        return d
+        return cast(defer.Deferred[None], d)
 
     def _set_presence(self, to="", show="", statuses=None, profile_key=C.PROF_KEY_NONE):
         return self.presence_set(jid.JID(to) if to else None, show, statuses, profile_key)
diff --git a/libervia/backend/core/xmpp.py b/libervia/backend/core/xmpp.py
index 7464ee71..b4804b8d 100644
--- a/libervia/backend/core/xmpp.py
+++ b/libervia/backend/core/xmpp.py
@@ -879,9 +879,8 @@ class SatXMPPEntity(core_types.SatXMPPEntity):
         subject: dict[str, str] | None = None,
         mess_type: str = "auto",
         extra: dict[str, Any] | None = None,
-        uid: str | None = None,
         no_trigger: bool = False,
-    ) -> defer.Deferred:
+    ) -> defer.Deferred[MessageData]:
         r"""Send a message to an entity
 
         @param to_jid: destinee of the message
@@ -893,9 +892,7 @@ class SatXMPPEntity(core_types.SatXMPPEntity):
         @param extra: extra data. Key can be:
             - info_type: information type, can be
                 TODO
-        @param uid: unique id:
-            should be unique at least in this XMPP session
-            if None, an uuid will be generated
+            - uid: unique id, if not provided an uuid will be generated
         @param no_trigger: if True, sendMessage[suffix] trigger will no be used
             useful when a message need to be sent without any modification
             /!\ this will also skip encryption methods!
@@ -904,13 +901,14 @@ class SatXMPPEntity(core_types.SatXMPPEntity):
             subject = {}
         if extra is None:
             extra = {}
+        uid = extra.get("uid") or str(uuid.uuid4())
 
         assert mess_type in C.MESS_TYPE_ALL
 
         data = {  # dict is similar to the one used in client.onMessage
             "from": self.jid,
             "to": to_jid,
-            "uid": uid or str(uuid.uuid4()),
+            "uid": uid,
             "message": message,
             "subject": subject,
             "type": mess_type,
@@ -1041,7 +1039,7 @@ class SatXMPPEntity(core_types.SatXMPPEntity):
         """
         if data["type"] != C.MESS_TYPE_GROUPCHAT:
             # we don't send groupchat message to bridge, as we get them back
-            # and they will be added the
+            # and they will be added then.
 
             # we need a message to send something
             if self.is_message_printable(data):
diff --git a/libervia/backend/plugins/plugin_comp_email_gateway/__init__.py b/libervia/backend/plugins/plugin_comp_email_gateway/__init__.py
index 20544a37..8a5ed6e2 100644
--- a/libervia/backend/plugins/plugin_comp_email_gateway/__init__.py
+++ b/libervia/backend/plugins/plugin_comp_email_gateway/__init__.py
@@ -992,12 +992,12 @@ class EmailGatewayComponent(GetDataHandler):
             except Exception:
                 log.exception("Can't parse mailing list email.")
         else:
+            extra["uid"] = message_id
             await client.sendMessage(
                 user_jid,
                 {"": body},
                 {"": subject} if subject else None,
                 extra=extra,
-                uid=message_id,
             )
 
     def parse_references(self, email: EmailMessage) -> list[str]:
diff --git a/tests/unit/test_email_gateway.py b/tests/unit/test_email_gateway.py
index f984dda9..da61a155 100644
--- a/tests/unit/test_email_gateway.py
+++ b/tests/unit/test_email_gateway.py
@@ -164,7 +164,7 @@ class TestEmailGatewayComponent:
         assert call_args[1] == {"": "Hello, world!\n"}
         assert call_args[2] == None
         client.sendMessage.assert_called_once_with(
-            to_jid, {"": "Hello, world!\n"}, None, extra={}, uid=None
+            to_jid, {"": "Hello, world!\n"}, None, extra={"uid": None}
         )
 
     @ed
@@ -207,9 +207,9 @@ class TestEmailGatewayComponent:
                             "delivered": True,
                         }
                     ],
-                }
+                },
+                "uid": None,
             },
-            uid=None,
         )
 
     @ed
@@ -275,8 +275,7 @@ class TestEmailGatewayComponent:
             to_jid,
             {"": "Hello, world!\n"},
             None,
-            extra={"headers": {"keywords": "test, example", "urgency": "high"}},
-            uid=None,
+            extra={"headers": {"keywords": "test, example", "urgency": "high"}, "uid": None},
         )
 
 
@@ -316,7 +315,7 @@ class TestPubsubService:
                 "media_subtype": "octet-stream",
                 "size": 123,
                 "hash_algo": "sha-256",
-                "file_hash": "0123456789abcdef",
+                "file_hash": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
                 "created": 123,
             },
             {
@@ -326,7 +325,7 @@ class TestPubsubService:
                 "media_subtype": "octet-stream",
                 "size": 456,
                 "hash_algo": "sha-256",
-                "file_hash": "0123456789abcdef",
+                "file_hash": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
                 "created": 123,
             },
         ]