diff --git a/apps/emqx/src/emqx_connection.erl b/apps/emqx/src/emqx_connection.erl
index 2d7435858..e0baab238 100644
--- a/apps/emqx/src/emqx_connection.erl
+++ b/apps/emqx/src/emqx_connection.erl
@@ -186,6 +186,8 @@
 -define(LIMITER_BYTES_IN, bytes).
 -define(LIMITER_MESSAGE_IN, messages).
 
+-define(LOG(Level, Data), ?SLOG(Level, (Data)#{tag => "MQTT"})).
+
 -dialyzer({no_match, [info/2]}).
 -dialyzer(
     {nowarn_function, [
@@ -282,7 +284,7 @@ async_set_keepalive(OS, Pid, Idle, Interval, Probes) ->
         {ok, Options} ->
             async_set_socket_options(Pid, Options);
         {error, {unsupported_os, OS}} ->
-            ?SLOG(warning, #{
+            ?LOG(warning, #{
                 msg => "Unsupported operation: set TCP keepalive",
                 os => OS
             }),
@@ -774,7 +776,7 @@ handle_timeout(TRef, Msg, State) ->
 %% Parse incoming data
 -compile({inline, [when_bytes_in/3]}).
 when_bytes_in(Oct, Data, State) ->
-    ?SLOG(debug, #{
+    ?LOG(debug, #{
         msg => "raw_bin_received",
         size => Oct,
         bin => binary_to_list(binary:encode_hex(Data)),
@@ -810,7 +812,7 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             parse_incoming(Rest, [Packet | Packets], NState)
     catch
         throw:{?FRAME_PARSE_ERROR, Reason} ->
-            ?SLOG(info, #{
+            ?LOG(info, #{
                 reason => Reason,
                 at_state => emqx_frame:describe_state(ParseState),
                 input_bytes => Data,
@@ -818,7 +820,7 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             }),
             {[{frame_error, Reason} | Packets], State};
         error:Reason:Stacktrace ->
-            ?SLOG(error, #{
+            ?LOG(error, #{
                 at_state => emqx_frame:describe_state(ParseState),
                 input_bytes => Data,
                 parsed_packets => Packets,
@@ -873,7 +875,7 @@ serialize_and_inc_stats_fun(#state{serialize = Serialize}) ->
     fun(Packet) ->
         try emqx_frame:serialize_pkt(Packet, Serialize) of
             <<>> ->
-                ?SLOG(warning, #{
+                ?LOG(warning, #{
                     msg => "packet_is_discarded",
                     reason => "frame_is_too_large",
                     packet => emqx_packet:format(Packet, hidden)
@@ -889,13 +891,13 @@ serialize_and_inc_stats_fun(#state{serialize = Serialize}) ->
         catch
             %% Maybe Never happen.
             throw:{?FRAME_SERIALIZE_ERROR, Reason} ->
-                ?SLOG(info, #{
+                ?LOG(info, #{
                     reason => Reason,
                     input_packet => Packet
                 }),
                 erlang:error({?FRAME_SERIALIZE_ERROR, Reason});
             error:Reason:Stacktrace ->
-                ?SLOG(error, #{
+                ?LOG(error, #{
                     input_packet => Packet,
                     exception => Reason,
                     stacktrace => Stacktrace
@@ -1018,7 +1020,7 @@ check_limiter(
             WhenOk(Data, Msgs, State#state{limiter = Limiter2});
         {pause, Time, Limiter2} ->
             ?SLOG(debug, #{
-                msg => "pause_time_dueto_rate_limit",
+                msg => "pause_time_due_to_rate_limit",
                 needs => Needs,
                 time_in_ms => Time
             }),
@@ -1070,7 +1072,7 @@ retry_limiter(#state{limiter = Limiter} = State) ->
             );
         {pause, Time, Limiter2} ->
             ?SLOG(debug, #{
-                msg => "pause_time_dueto_rate_limit",
+                msg => "pause_time_due_to_rate_limit",
                 types => Types,
                 time_in_ms => Time
             }),
diff --git a/apps/emqx/src/emqx_ws_connection.erl b/apps/emqx/src/emqx_ws_connection.erl
index d4bc0f3ed..038f3e98e 100644
--- a/apps/emqx/src/emqx_ws_connection.erl
+++ b/apps/emqx/src/emqx_ws_connection.erl
@@ -128,6 +128,8 @@
 -dialyzer({no_match, [info/2]}).
 -dialyzer({nowarn_function, [websocket_init/1]}).
 
+-define(LOG(Level, Data), ?SLOG(Level, (Data)#{tag => "MQTT"})).
+
 %%--------------------------------------------------------------------
 %% Info, Stats
 %%--------------------------------------------------------------------
@@ -401,7 +403,7 @@ get_peer_info(Type, Listener, Req, Opts) ->
 websocket_handle({binary, Data}, State) when is_list(Data) ->
     websocket_handle({binary, iolist_to_binary(Data)}, State);
 websocket_handle({binary, Data}, State) ->
-    ?SLOG(debug, #{
+    ?LOG(debug, #{
         msg => "raw_bin_received",
         size => iolist_size(Data),
         bin => binary_to_list(binary:encode_hex(Data)),
@@ -428,7 +430,7 @@ websocket_handle({Frame, _}, State) when Frame =:= ping; Frame =:= pong ->
     return(State);
 websocket_handle({Frame, _}, State) ->
     %% TODO: should not close the ws connection
-    ?SLOG(error, #{msg => "unexpected_frame", frame => Frame}),
+    ?LOG(error, #{msg => "unexpected_frame", frame => Frame}),
     shutdown(unexpected_ws_frame, State).
 websocket_info({call, From, Req}, State) ->
     handle_call(From, Req, State);
@@ -714,7 +716,7 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             parse_incoming(Rest, [{incoming, Packet} | Packets], NState)
     catch
         throw:{?FRAME_PARSE_ERROR, Reason} ->
-            ?SLOG(info, #{
+            ?LOG(info, #{
                 reason => Reason,
                 at_state => emqx_frame:describe_state(ParseState),
                 input_bytes => Data
@@ -722,7 +724,7 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             FrameError = {frame_error, Reason},
             {[{incoming, FrameError} | Packets], State};
         error:Reason:Stacktrace ->
-            ?SLOG(error, #{
+            ?LOG(error, #{
                 at_state => emqx_frame:describe_state(ParseState),
                 input_bytes => Data,
                 exception => Reason,
@@ -812,7 +814,7 @@ serialize_and_inc_stats_fun(#state{serialize = Serialize}) ->
     fun(Packet) ->
         try emqx_frame:serialize_pkt(Packet, Serialize) of
             <<>> ->
-                ?SLOG(warning, #{
+                ?LOG(warning, #{
                     msg => "packet_discarded",
                     reason => "frame_too_large",
                     packet => emqx_packet:format(Packet)
@@ -828,13 +830,13 @@ serialize_and_inc_stats_fun(#state{serialize = Serialize}) ->
         catch
             %% Maybe Never happen.
             throw:{?FRAME_SERIALIZE_ERROR, Reason} ->
-                ?SLOG(info, #{
+                ?LOG(info, #{
                     reason => Reason,
                     input_packet => Packet
                 }),
                 erlang:error({?FRAME_SERIALIZE_ERROR, Reason});
             error:Reason:Stacktrace ->
-                ?SLOG(error, #{
+                ?LOG(error, #{
                     input_packet => Packet,
                     exception => Reason,
                     stacktrace => Stacktrace