diff --git a/src/aleph/sdk/models.py b/src/aleph/sdk/models.py
index f8cdec9d..3de92c74 100644
--- a/src/aleph/sdk/models.py
+++ b/src/aleph/sdk/models.py
@@ -37,12 +37,15 @@ class Post(BaseModel):
     )
     address: str = Field(description="The address of the sender of the POST message")
     ref: Optional[str] = Field(description="Other message referenced by this one")
-    channel: str = Field(description="The channel where the POST message was published")
+    channel: Optional[str] = Field(description="The channel where the POST message was published")
     created: datetime = Field(description="The time when the POST message was created")
     last_updated: datetime = Field(
         description="The time when the POST message was last updated"
     )
 
+    class Config:
+        allow_extra = False
+
 
 class PostsResponse(PaginationResponse):
     """Response from an Aleph node API on the path /api/v0/posts.json"""
diff --git a/src/aleph/sdk/node/__init__.py b/src/aleph/sdk/node/__init__.py
index 1477ac2c..f95256cc 100644
--- a/src/aleph/sdk/node/__init__.py
+++ b/src/aleph/sdk/node/__init__.py
@@ -98,6 +98,8 @@ def add(self, messages: Union[AlephMessage, Iterable[AlephMessage]]):
         if isinstance(messages, typing.get_args(AlephMessage)):
             messages = [messages]
 
+        messages = list(messages)
+
         message_data = (message_to_model(message) for message in messages)
         MessageModel.insert_many(message_data).on_conflict_replace().execute()
 
@@ -105,16 +107,18 @@ def add(self, messages: Union[AlephMessage, Iterable[AlephMessage]]):
         post_data = []
         amend_messages = []
         for message in messages:
-            if message.item_type != MessageType.post:
+            if message.type != MessageType.post.value:
                 continue
             if message.content.type == "amend":
                 amend_messages.append(message)
-            else:
-                post = message_to_post(message).dict()
-                post_data.append(post)
-                # Check if we can now add any amend messages that had missing refs
-                if message.item_hash in self.missing_posts:
-                    amend_messages += self.missing_posts.pop(message.item_hash)
+                continue
+            post = message_to_post(message).dict()
+            post["chain"] = message.chain.value
+            post["tags"] = message.content.content.get("tags", None)
+            post_data.append(post)
+            # Check if we can now add any amend messages that had missing refs
+            if message.item_hash in self.missing_posts:
+                amend_messages += self.missing_posts.pop(message.item_hash)
 
         PostModel.insert_many(post_data).on_conflict_replace().execute()
 
diff --git a/src/aleph/sdk/node/post.py b/src/aleph/sdk/node/post.py
index b68a421d..e4af0807 100644
--- a/src/aleph/sdk/node/post.py
+++ b/src/aleph/sdk/node/post.py
@@ -58,7 +58,7 @@ def message_to_post(message: PostMessage) -> Post:
             "ref": message.content.ref if hasattr(message.content, "ref") else None,
             "channel": message.channel,
             "created": datetime.fromtimestamp(message.time),
-            "last_updated": datetime.fromtimestamp(message.time),
+            "last_updated": datetime.fromtimestamp(message.time)
         }
     )
 
diff --git a/tests/unit/test_node_get.py b/tests/unit/test_node_get.py
index 48bff3b8..5f80d2c6 100644
--- a/tests/unit/test_node_get.py
+++ b/tests/unit/test_node_get.py
@@ -13,7 +13,7 @@
 
 from aleph.sdk.chains.ethereum import get_fallback_account
 from aleph.sdk.exceptions import MessageNotFoundError
-from aleph.sdk.node import MessageCache
+from aleph.sdk.node import MessageCache, message_to_post
 
 
 @pytest.mark.asyncio
@@ -137,7 +137,7 @@ def class_teardown(self):
     @pytest.mark.asyncio
     async def test_addresses(self):
         items = (await self.cache.get_posts(addresses=[self.messages[1].sender])).posts
-        assert items[0] == self.messages[1]
+        assert items[0] == message_to_post(self.messages[1])
 
     @pytest.mark.asyncio
     async def test_tags(self):
@@ -153,15 +153,16 @@ async def test_types(self):
 
     @pytest.mark.asyncio
     async def test_channels(self):
+        print(self.messages[1])
         assert (await self.cache.get_posts(channels=[self.messages[1].channel])).posts[
             0
-        ] == self.messages[1]
+        ] == message_to_post(self.messages[1])
 
     @pytest.mark.asyncio
     async def test_chains(self):
         assert (await self.cache.get_posts(chains=[self.messages[1].chain])).posts[
             0
-        ] == self.messages[1]
+        ] == message_to_post(self.messages[1])
 
 
 @pytest.mark.asyncio