diff --git a/src/emqx_alarm_handler.erl b/src/emqx_alarm_handler.erl
index e37c530a6..b57a04380 100644
--- a/src/emqx_alarm_handler.erl
+++ b/src/emqx_alarm_handler.erl
@@ -154,16 +154,21 @@ encode_alarm({AlarmId, #alarm{severity  = Severity,
                               title     = Title,
                               summary   = Summary,
                               timestamp = Ts}}) ->
-    emqx_json:safe_encode([{id, maybe_to_binary(AlarmId)},
-                           {desc, [{severity, Severity},
-                                   {title, iolist_to_binary(Title)},
-                                   {summary, iolist_to_binary(Summary)},
-                                   {timestamp, Ts}]}]);
+    Descr = #{severity => Severity,
+              title => iolist_to_binary(Title),
+              summary => iolist_to_binary(Summary),
+              timestamp => Ts
+             },
+    emqx_json:safe_encode(#{id => maybe_to_binary(AlarmId),
+                            desc => Descr
+                           });
+
 encode_alarm({AlarmId, undefined}) ->
-    emqx_json:safe_encode([{id, maybe_to_binary(AlarmId)}]);
+    emqx_json:safe_encode(#{id => maybe_to_binary(AlarmId)});
 encode_alarm({AlarmId, AlarmDesc}) ->
-    emqx_json:safe_encode([{id, maybe_to_binary(AlarmId)},
-                           {desc, maybe_to_binary(AlarmDesc)}]).
+    emqx_json:safe_encode(#{id => maybe_to_binary(AlarmId),
+                            desc => maybe_to_binary(AlarmDesc)
+                           }).
 
 alarm_msg(Topic, Payload) ->
     Msg = emqx_message:make(?MODULE, Topic, Payload),
diff --git a/src/emqx_json.erl b/src/emqx_json.erl
index b54340963..27792c36c 100644
--- a/src/emqx_json.erl
+++ b/src/emqx_json.erl
@@ -51,11 +51,11 @@
 
 -spec(encode(json_term()) -> json_text()).
 encode(Term) ->
-    jsx:encode(Term).
+    jiffy:encode(Term).
 
 -spec(encode(json_term(), encode_options()) -> json_text()).
 encode(Term, Opts) ->
-    jsx:encode(Term, Opts).
+    jiffy:encode(Term, Opts).
 
 -spec(safe_encode(json_term())
       -> {ok, json_text()} | {error, Reason :: term()}).
@@ -73,12 +73,11 @@ safe_encode(Term, Opts) ->
     end.
 
 -spec(decode(json_text()) -> json_term()).
-decode(Json) ->
-    case jsx:decode(Json) of {Term} -> Term; Other -> Other end.
+decode(Json) -> decode(Json, []).
 
 -spec(decode(json_text(), decode_options()) -> json_term()).
 decode(Json, Opts) ->
-    case jsx:decode(Json, Opts) of {Term} -> Term; Other -> Other end.
+    case jiffy:decode(Json, Opts) of {Term} -> Term; Other -> Other end.
 
 -spec(safe_decode(json_text())
       -> {ok, json_term()} | {error, Reason :: term()}).
diff --git a/test/emqx_json_SUITE.erl b/test/emqx_json_SUITE.erl
index ffe900ef4..b08ca37c9 100644
--- a/test/emqx_json_SUITE.erl
+++ b/test/emqx_json_SUITE.erl
@@ -21,24 +21,76 @@
 
 -include_lib("eunit/include/eunit.hrl").
 
--define(DEC_OPTS, [{labels, atom}, return_maps]).
+-import(emqx_json,
+        [ encode/1
+        , decode/1
+        , decode/2
+        ]).
+
+%%--------------------------------------------------------------------
+%% Erlang                     JSON              Erlang
+%% -------------------------------------------------------------------
+%%
+%% null                       -> null           -> null
+%% true                       -> true           -> true
+%% false                      -> false          -> false
+%% "hi"                       -> [104, 105]     -> [104, 105]
+%% <<"hi">>                   -> "hi"           -> <<"hi">>
+%% hi                         -> "hi"           -> <<"hi">>
+%% 1                          -> 1              -> 1
+%% 1.25                       -> 1.25           -> 1.25
+%% []                         -> []             -> []
+%% [true, 1.0]                -> [true, 1.0]    -> [true, 1.0]
+%% {[]}                       -> {}             -> {[]}
+%% {[{foo, bar}]}             -> {"foo": "bar"} -> {[{<<"foo">>, <<"bar">>}]}
+%% {[{<<"foo">>, <<"bar">>}]} -> {"foo": "bar"} -> {[{<<"foo">>, <<"bar">>}]}
+%% #{<<"foo">> => <<"bar">>}  -> {"foo": "bar"} -> #{<<"foo">> => <<"bar">>}
+%%--------------------------------------------------------------------
 
 all() -> emqx_ct:all(?MODULE).
 
 t_decode_encode(_) ->
-    JsonText = <<"{\"library\": \"jsx\", \"awesome\": true}">>,
-    JsonTerm = emqx_json:decode(JsonText),
-    JsonMaps = #{library => <<"jsx">>, awesome => true},
-    ?assertEqual(JsonText, emqx_json:encode(JsonTerm, [{space, 1}])),
-    ?assertEqual(JsonMaps, emqx_json:decode(JsonText, ?DEC_OPTS)).
+    null = decode(encode(null)),
+    true = decode(encode(true)),
+    false = decode(encode(false)),
+    "hi" = decode(encode("hi")),
+    <<"hi">> = decode(encode(hi)),
+    1 = decode(encode(1)),
+    1.25 = decode(encode(1.25)),
+    [] = decode(encode([])),
+    [true, 1] = decode(encode([true, 1])),
+    [] = decode(encode({[]})),
+    [{<<"foo">>, <<"bar">>}] = decode(encode({[{foo, bar}]})),
+    [{<<"foo">>, <<"bar">>}] = decode(encode({[{<<"foo">>, <<"bar">>}]})),
+    #{<<"foo">> := <<"bar">>} = decode(encode(#{<<"foo">> => <<"bar">>}), [return_maps]),
+    JsonText = <<"{\"bool\":true,\"int\":10,\"foo\":\"bar\"}">>,
+    JsonMaps = #{<<"bool">> => true,
+                 <<"int">>  => 10,
+                 <<"foo">>  => <<"bar">>
+                },
+    ?assertEqual(JsonText, encode({decode(JsonText)})),
+    ?assertEqual(JsonMaps, decode(JsonText, [return_maps])).
 
 t_safe_decode_encode(_) ->
-    JsonText = <<"{\"library\": \"jsx\", \"awesome\": true}">>,
-    {ok, JsonTerm} = emqx_json:safe_decode(JsonText),
-    JsonMaps = #{library => <<"jsx">>, awesome => true},
-    ?assertEqual({ok, JsonText}, emqx_json:safe_encode(JsonTerm, [{space, 1}])),
-    ?assertEqual({ok, JsonMaps}, emqx_json:safe_decode(JsonText, ?DEC_OPTS)),
-    BadJsonText = <<"{\"library\", \"awesome\": true}">>,
-    ?assertEqual({error, badarg}, emqx_json:safe_decode(BadJsonText)),
-    {error, badarg} = emqx_json:safe_encode({a, {b ,1}}).
+    safe_encode_decode(null),
+    safe_encode_decode(true),
+    safe_encode_decode(false),
+    "hi" = safe_encode_decode("hi"),
+    <<"hi">> = safe_encode_decode(hi),
+    1 = safe_encode_decode(1),
+    1.25 = safe_encode_decode(1.25),
+    [] = safe_encode_decode([]),
+    [true, 1] = safe_encode_decode([true, 1]),
+    [] = safe_encode_decode({[]}),
+    [{<<"foo">>, <<"bar">>}] = safe_encode_decode({[{foo, bar}]}),
+    [{<<"foo">>, <<"bar">>}] = safe_encode_decode({[{<<"foo">>, <<"bar">>}]}),
+    {ok, Json} = emqx_json:safe_encode(#{<<"foo">> => <<"bar">>}),
+    {ok, #{<<"foo">> := <<"bar">>}} = emqx_json:safe_decode(Json, [return_maps]).
+
+safe_encode_decode(Term) ->
+    {ok, Json} = emqx_json:safe_encode(Term),
+    case emqx_json:safe_decode(Json) of
+        {ok, {NTerm}} -> NTerm;
+        {ok, NTerm}   -> NTerm
+    end.