diff --git a/api/message/json/codec_test.go b/api/message/json/codec_test.go
new file mode 100644
index 0000000..6f846ce
--- /dev/null
+++ b/api/message/json/codec_test.go
@@ -0,0 +1,78 @@
+package json
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/eosswedenorg/thalos/api/message"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestJson_EncodeActionTrace(t *testing.T) {
+	dataJson, err := json.Marshal(map[string]string{
+		"from":     "account1",
+		"to":       "account2",
+		"quantity": "1000.0000 WAX",
+	})
+
+	assert.NoError(t, err)
+
+	msg := message.ActionTrace{
+		TxID:      "ed3b8e853647971cf8296f004c3a1aeac255f082b2cb3c12cc3222e2d7c174ab",
+		BlockNum:  267372365,
+		Timestamp: time.Unix(1048267389, int64(time.Millisecond)*500).UTC(),
+		Name:      "transfer",
+		Contract:  "eosio",
+		Receiver:  "account2",
+		Data:      dataJson,
+		HexData:   hex.EncodeToString(dataJson),
+		Authorization: []message.PermissionLevel{
+			{Actor: "account1", Permission: "active"},
+		},
+		Except: "errstr",
+		Error:  2,
+		Return: []byte{0xde, 0xad, 0xbe, 0xef},
+	}
+
+	expected := `{"tx_id":"ed3b8e853647971cf8296f004c3a1aeac255f082b2cb3c12cc3222e2d7c174ab","blocknum":267372365,"blocktimestamp":"2003-03-21T17:23:09.5Z","name":"transfer","contract":"eosio","receiver":"account2","data":"eyJmcm9tIjoiYWNjb3VudDEiLCJxdWFudGl0eSI6IjEwMDAuMDAwMCBXQVgiLCJ0byI6ImFjY291bnQyIn0=","hex_data":"7b2266726f6d223a226163636f756e7431222c227175616e74697479223a22313030302e3030303020574158222c22746f223a226163636f756e7432227d","authorization":[{"actor":"account1","permission":"active"}],"except":"errstr","error":2,"return":"3q2+7w=="}`
+
+	data, err := json.Marshal(msg)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, string(data))
+}
+
+func TestJson_DecodeActionTrace(t *testing.T) {
+	dataJson, err := json.Marshal(map[string]string{
+		"from":     "account1",
+		"to":       "account2",
+		"quantity": "1000.0000 WAX",
+	})
+
+	assert.NoError(t, err)
+
+	expected := message.ActionTrace{
+		TxID:      "952989f7464237b6cf9926e533ecd331df6794ed07564bd052bc368cbd65b4bc",
+		BlockNum:  8723971,
+		Timestamp: time.Unix(1718957306, int64(time.Millisecond)*500).UTC(),
+		Name:      "transfer",
+		Contract:  "eosio",
+		Receiver:  "account2",
+		Data:      dataJson,
+		HexData:   hex.EncodeToString(dataJson),
+		Authorization: []message.PermissionLevel{
+			{Actor: "account1", Permission: "active"},
+		},
+		Except: "errstr",
+		Error:  2,
+		Return: []byte{0xde, 0xad, 0xbe, 0xef},
+	}
+
+	input := `{"tx_id":"952989f7464237b6cf9926e533ecd331df6794ed07564bd052bc368cbd65b4bc","blocknum":8723971,"blocktimestamp":"2024-06-21T08:08:26.5Z","name":"transfer","contract":"eosio","receiver":"account2","data":"eyJmcm9tIjoiYWNjb3VudDEiLCJxdWFudGl0eSI6IjEwMDAuMDAwMCBXQVgiLCJ0byI6ImFjY291bnQyIn0=","hex_data":"7b2266726f6d223a226163636f756e7431222c227175616e74697479223a22313030302e3030303020574158222c22746f223a226163636f756e7432227d","authorization":[{"actor":"account1","permission":"active"}],"except":"errstr","error":2,"return":"3q2+7w=="}`
+
+	msg := message.ActionTrace{}
+	err = json.Unmarshal([]byte(input), &msg)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, msg)
+}