diff --git a/apps/emqx/include/emqx_trace.hrl b/apps/emqx/include/emqx_trace.hrl
index a2f77c044..f273c2dbc 100644
--- a/apps/emqx/include/emqx_trace.hrl
+++ b/apps/emqx/include/emqx_trace.hrl
@@ -33,7 +33,7 @@
     extra = #{} :: map() | '_',
     start_at :: integer() | undefined | '_',
     end_at :: integer() | undefined | '_',
-    formatter = plain :: plain | json
+    formatter = plain :: plain | json | '_'
 }).
 
 -define(SHARD, ?COMMON_SHARD).
diff --git a/apps/emqx/src/emqx_trace/emqx_trace_handler.erl b/apps/emqx/src/emqx_trace/emqx_trace_handler.erl
index d80fa70ec..98577d0b9 100644
--- a/apps/emqx/src/emqx_trace/emqx_trace_handler.erl
+++ b/apps/emqx/src/emqx_trace/emqx_trace_handler.erl
@@ -46,7 +46,8 @@
     name := binary(),
     type := clientid | topic | ip_address,
     filter := emqx_types:clientid() | emqx_types:topic() | emqx_trace:ip_address(),
-    payload_encode := text | hidden | hex
+    payload_encode := text | hidden | hex,
+    formatter => json | plain
 }.
 
 -define(CONFIG(_LogFile_), #{