diff --git a/src/event_pusher/mod_event_pusher_push_rdbms.erl b/src/event_pusher/mod_event_pusher_push_rdbms.erl
index cdde39a887b..6970c624154 100644
--- a/src/event_pusher/mod_event_pusher_push_rdbms.erl
+++ b/src/event_pusher/mod_event_pusher_push_rdbms.erl
@@ -81,6 +81,7 @@ decode_row({NodeID, PubSubBin, FormJSON}) ->
      NodeID,
      decode_form(FormJSON)}.
 
+-spec encode_form(mod_event_pusher_push:form()) -> iodata().
 encode_form(Form) ->
     jiffy:encode(Form).
 
diff --git a/src/event_pusher/mod_event_pusher_rabbit.erl b/src/event_pusher/mod_event_pusher_rabbit.erl
index 98118f17e72..7fe2ed4c0b1 100644
--- a/src/event_pusher/mod_event_pusher_rabbit.erl
+++ b/src/event_pusher/mod_event_pusher_rabbit.erl
@@ -178,7 +178,7 @@ user_topic_routing_key(JID, Topic) ->
 -spec presence_msg(JID :: jid:jid(), Status :: atom()) -> binary().
 presence_msg(JID, Status) ->
     Msg = #{user_id => jid:to_binary(jid:to_lower(JID)), present => is_user_online(Status)},
-    jiffy:encode(Msg).
+    iolist_to_binary(jiffy:encode(Msg)).
 
 -spec chat_msg(From :: jid:jid(), To :: jid:jid(), UserMsg :: binary()) ->
     binary().
@@ -186,7 +186,7 @@ chat_msg(From, To, UserMsg) ->
     Msg = #{to_user_id => jid:to_binary(jid:to_lower(To)),
             message => UserMsg,
             from_user_id => jid:to_binary(jid:to_lower(From))},
-    jiffy:encode(Msg).
+    iolist_to_binary(jiffy:encode(Msg)).
 
 -spec is_user_online(online | offline) -> boolean().
 is_user_online(online) -> true;
diff --git a/src/mongoose_client_api/mongoose_client_api_sse.erl b/src/mongoose_client_api/mongoose_client_api_sse.erl
index 786dfba6d69..118c033d3f2 100644
--- a/src/mongoose_client_api/mongoose_client_api_sse.erl
+++ b/src/mongoose_client_api/mongoose_client_api_sse.erl
@@ -64,11 +64,11 @@ terminate(_Reason, _Req, _State) ->
     ok.
 
 maybe_send_message_event(<<"chat">>, Packet, Timestamp, #{id := ID} = State) ->
-    Data = jiffy:encode(mongoose_client_api_messages:encode(Packet, Timestamp)),
+    Data = iolist_to_binary(jiffy:encode(mongoose_client_api_messages:encode(Packet, Timestamp))),
     Event = #{id => integer_to_binary(ID), event => <<"message">>, data => Data},
     {send, Event, State#{id := ID + 1}};
 maybe_send_message_event(<<"groupchat">>, Packet, Timestamp, #{id := ID} = State) ->
-    Data = jiffy:encode(mongoose_client_api_rooms_messages:encode(Packet, Timestamp)),
+    Data = iolist_to_binary(jiffy:encode(mongoose_client_api_rooms_messages:encode(Packet, Timestamp))),
     Event = #{id => integer_to_binary(ID), event => <<"room.message">>, data => Data},
     {send, Event, State#{id := ID + 1}};
 maybe_send_message_event(_, _, _, State) ->
diff --git a/src/muc/mod_muc_rdbms.erl b/src/muc/mod_muc_rdbms.erl
index ca8f4c5ed3f..ca21a3ce0ab 100644
--- a/src/muc/mod_muc_rdbms.erl
+++ b/src/muc/mod_muc_rdbms.erl
@@ -219,7 +219,7 @@ store_nick_transaction(HostType, MucHost, Jid, Nick, true) ->
         Error -> Error
     end.
 
--spec store_room_transaction(mongooseim:host_type(), muc_host(), jid:luser(), binary(), term()) -> ok.
+-spec store_room_transaction(mongooseim:host_type(), muc_host(), jid:luser(), iodata(), term()) -> ok.
 store_room_transaction(HostType, MucHost, RoomName, ExtOpts, Affs) ->
     execute_insert_room(HostType, MucHost, RoomName, ExtOpts),
     Result = execute_select_room_id(HostType, MucHost, RoomName),
@@ -249,7 +249,7 @@ forget_room_transaction(HostType, MucHost, RoomName) ->
 
 %% Execute call functions
 
--spec execute_insert_room(mongooseim:host_type(), muc_host(), jid:luser(), binary()) -> ok.
+-spec execute_insert_room(mongooseim:host_type(), muc_host(), jid:luser(), iodata()) -> ok.
 execute_insert_room(HostType, MucHost, RoomName, ExtOpts) ->
     Args = [MucHost, RoomName, ExtOpts],
     execute_successfully(HostType, muc_insert_room, Args),
diff --git a/src/rdbms/mongoose_rdbms.erl b/src/rdbms/mongoose_rdbms.erl
index 2a7abde452a..0167536eb29 100644
--- a/src/rdbms/mongoose_rdbms.erl
+++ b/src/rdbms/mongoose_rdbms.erl
@@ -158,8 +158,8 @@
 -type rdbms_msg() :: {sql_query, _}
                    | {sql_transaction, fun()}
                    | {sql_dirty, fun()}
-                   | {sql_execute, atom(), [binary() | boolean() | integer()]}
-                   | {sql_execute_wrapped, atom(), [binary() | boolean() | integer()], request_wrapper()}.
+                   | {sql_execute, atom(), [iodata() | boolean() | integer()]}
+                   | {sql_execute_wrapped, atom(), [iodata() | boolean() | integer()], request_wrapper()}.
 -type single_query_result() :: {selected, [tuple()]} |
                                {updated, non_neg_integer() | undefined} |
                                {updated, non_neg_integer(), [tuple()]} |