diff --git a/apps/emqx/src/emqx_connection.erl b/apps/emqx/src/emqx_connection.erl
index 2d74358582..2e3f8aea5d 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
@@ -938,7 +940,7 @@ handle_info(activate_socket, State = #state{sockstate = OldSst}) ->
     end;
 handle_info({sock_error, Reason}, State) ->
     case Reason =/= closed andalso Reason =/= einval of
-        true -> ?SLOG(warning, #{msg => "socket_error", reason => Reason});
+        true -> ?LOG(warning, #{msg => "socket_error", reason => Reason});
         false -> ok
     end,
     handle_info({sock_closed, Reason}, close_socket(State));
@@ -1017,7 +1019,7 @@ check_limiter(
         {ok, Limiter2} ->
             WhenOk(Data, Msgs, State#state{limiter = Limiter2});
         {pause, Time, Limiter2} ->
-            ?SLOG(debug, #{
+            ?LOG(debug, #{
                 msg => "pause_time_dueto_rate_limit",
                 needs => Needs,
                 time_in_ms => Time
@@ -1069,7 +1071,7 @@ retry_limiter(#state{limiter = Limiter} = State) ->
                 }
             );
         {pause, Time, Limiter2} ->
-            ?SLOG(debug, #{
+            ?LOG(debug, #{
                 msg => "pause_time_dueto_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 d4bc0f3edc..1e6affe373 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
 %%--------------------------------------------------------------------
@@ -210,7 +212,7 @@ init(Req, #{listener := {Type, Listener}} = Opts) ->
     },
     case check_origin_header(Req, Opts) of
         {error, Reason} ->
-            ?SLOG(error, #{msg => "invalid_origin_header", reason => Reason}),
+            ?LOG(error, #{msg => "invalid_origin_header", reason => Reason}),
             {ok, cowboy_req:reply(403, Req), WsOpts};
         ok ->
             parse_sec_websocket_protocol(Req, Opts, WsOpts)
@@ -362,10 +364,10 @@ get_ws_cookie(Req) ->
         cowboy_req:parse_cookies(Req)
     catch
         error:badarg ->
-            ?SLOG(error, #{msg => "bad_cookie"}),
+            ?LOG(error, #{msg => "bad_cookie"}),
             undefined;
         Error:Reason ->
-            ?SLOG(error, #{
+            ?LOG(error, #{
                 msg => "failed_to_parse_cookie",
                 exception => Error,
                 reason => Reason
@@ -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);
@@ -604,7 +606,7 @@ check_limiter(
         {ok, Limiter2} ->
             WhenOk(Data, Msgs, State#state{limiter = Limiter2});
         {pause, Time, Limiter2} ->
-            ?SLOG(debug, #{
+            ?LOG(debug, #{
                 msg => "pause_time_due_to_rate_limit",
                 needs => Needs,
                 time_in_ms => Time
@@ -657,7 +659,7 @@ retry_limiter(#state{limiter = Limiter} = State) ->
                 }
             );
         {pause, Time, Limiter2} ->
-            ?SLOG(debug, #{
+            ?LOG(debug, #{
                 msg => "pause_time_due_to_rate_limit",
                 types => Types,
                 time_in_ms => Time
@@ -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
@@ -1050,7 +1052,7 @@ check_max_connection(Type, Listener) ->
                         current => Curr,
                         msg => "websocket_max_connections_limited"
                     },
-                    ?SLOG(warning, Reason),
+                    ?LOG(warning, Reason),
                     {denny, Reason}
             end
     end.