diff --git a/src/aleph/web/controllers/messages.py b/src/aleph/web/controllers/messages.py
index faf64b5f5..d54e70dbe 100644
--- a/src/aleph/web/controllers/messages.py
+++ b/src/aleph/web/controllers/messages.py
@@ -57,17 +57,21 @@
 class BaseMessageQueryParams(BaseModel):
     sort_by: SortBy = Field(
         default=SortBy.TIME,
+        alias="sortBy",
         description="Key to use to sort the messages. "
         "'time' uses the message time field. "
         "'tx-time' uses the first on-chain confirmation time.",
     )
     sort_order: SortOrder = Field(
         default=SortOrder.DESCENDING,
+        alias="sortOrder",
         description="Order in which messages should be listed: "
         "-1 means most recent messages first, 1 means older messages first.",
     )
     message_type: Optional[MessageType] = Field(
-        default=None, alias="msgType", description="Message type. Deprecated: use msgTypes instead"
+        default=None,
+        alias="msgType",
+        description="Message type. Deprecated: use msgTypes instead",
     )
     message_types: Optional[List[MessageType]] = Field(
         default=None, alias="msgTypes", description="Accepted message types."
diff --git a/src/aleph/web/controllers/posts.py b/src/aleph/web/controllers/posts.py
index 70cbd57f9..13a25d574 100644
--- a/src/aleph/web/controllers/posts.py
+++ b/src/aleph/web/controllers/posts.py
@@ -70,12 +70,14 @@ class PostQueryParams(BaseModel):
     )
     sort_by: SortBy = Field(
         default=SortBy.TIME,
+        alias="sortBy",
         description="Key to use to sort the posts. "
         "'time' uses the post creation time field. "
         "'tx-time' uses the first on-chain confirmation time.",
     )
     sort_order: SortOrder = Field(
         default=SortOrder.DESCENDING,
+        alias="sortOrder",
         description="Order in which messages should be listed: "
         "-1 means most recent messages first, 1 means older messages first.",
     )
diff --git a/tests/api/test_list_messages.py b/tests/api/test_list_messages.py
index 8e81f8ad7..668b36df8 100644
--- a/tests/api/test_list_messages.py
+++ b/tests/api/test_list_messages.py
@@ -272,8 +272,8 @@ async def fetch_messages_filter_time(
 ) -> aiohttp.ClientResponse:
 
     params: Dict[str, Union[float, int, str]] = {
-        "sort_by": sort_by,
-        "sort_order": sort_order,
+        "sortBy": sort_by,
+        "sortOrder": sort_order,
     }
     if start:
         params["startDate"] = start
@@ -373,7 +373,7 @@ async def fetch_messages_with_pagination(
 ):
     return await api_client.get(
         MESSAGES_URI,
-        params={"page": page, "pagination": pagination, "sort_order": sort_order},
+        params={"page": page, "pagination": pagination, "sortOrder": sort_order},
     )
 
 
@@ -465,18 +465,15 @@ def get_confirmed_time(msg: Dict) -> Tuple[float, float]:
             # Return a high timestamp to make unconfirmed messages last
             return dt.datetime(3000, 1, 1).timestamp(), msg["time"]
 
-    sorted_messages_by_time = sorted(fixture_messages, key=get_confirmed_time)
+    sorted_messages_by_time = list(
+        sorted(fixture_messages, key=get_confirmed_time, reverse=sort_order == -1)
+    )
 
-    # Descending order
     messages = await fetch_messages_filter_time_expect_success(
         ccn_api_client, sort_by="tx-time", sort_order=sort_order
     )
     assert_messages_equal(messages=messages, expected_messages=sorted_messages_by_time)
 
-    if sort_order == -1:
-        # Note: list() is used for mypy
-        sorted_messages_by_time = list(reversed(sorted_messages_by_time))
-
     assert [msg["item_hash"] for msg in messages] == [
         msg["item_hash"] for msg in sorted_messages_by_time
     ]