diff --git a/dataeq/dataeq.go b/dataeq/dataeq.go
index f69b03e..567b386 100644
--- a/dataeq/dataeq.go
+++ b/dataeq/dataeq.go
@@ -28,27 +28,22 @@ func New(marshal Marshal, unmarshal Unmarshal) DataFormat {
 	}
 }
 
-// ConvertByte unmarshals a byte string to `interface{}`.
-func (df DataFormat) ConvertByte(b []byte) (interface{}, error) {
-	var d interface{}
-	err := df.unmarshal(b, &d)
-	if err == nil {
-		return d, nil
-	}
-	return nil, err
+// ConvertByte unmarshals a byte string to dst.
+func (df DataFormat) ConvertByte(b []byte, dst interface{}) error {
+	return df.unmarshal(b, dst)
 }
 
-// Convert converts value to byte string and unmarshals the byte string to `interface{}`.
+// Convert converts value to byte string and unmarshals the byte string to dst.
 // Convert can be used to normalize the value to compare with the other value.
-func (df DataFormat) Convert(x interface{}) (interface{}, error) {
+func (df DataFormat) Convert(x interface{}, dst interface{}) error {
 	if a, ok := x.([]byte); ok {
-		return df.ConvertByte(a)
+		return df.ConvertByte(a, dst)
 	}
 	b, err := df.marshal(x)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	return df.ConvertByte(b)
+	return df.ConvertByte(b, dst)
 }
 
 // Equal returns true if two arguments are equal.
@@ -56,12 +51,12 @@ func (df DataFormat) Equal(x, y interface{}) (bool, error) {
 	if reflect.DeepEqual(x, y) {
 		return true, nil
 	}
-	a, err := df.Convert(x)
-	if err != nil {
+	var a interface{}
+	if err := df.Convert(x, &a); err != nil {
 		return false, err
 	}
-	b, err := df.Convert(y)
-	if err != nil {
+	var b interface{}
+	if err := df.Convert(y, &b); err != nil {
 		return false, err
 	}
 	return reflect.DeepEqual(a, b), nil
diff --git a/dataeq/dataeq_test.go b/dataeq/dataeq_test.go
index dce42f3..ae9c131 100644
--- a/dataeq/dataeq_test.go
+++ b/dataeq/dataeq_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestJSON_ConvertByte(t *testing.T) {
+	t.Parallel()
 	data := []struct {
 		title   string
 		b       []byte
@@ -51,7 +52,9 @@ func TestJSON_ConvertByte(t *testing.T) {
 	for _, d := range data {
 		d := d
 		t.Run(d.title, func(t *testing.T) {
-			a, err := dataeq.JSON.ConvertByte(d.b)
+			t.Parallel()
+			var a interface{}
+			err := dataeq.JSON.ConvertByte(d.b, &a)
 			if d.isError {
 				require.NotNil(t, err)
 				return
@@ -71,6 +74,7 @@ func (m *invalidMarshaler) MarshalJSON() ([]byte, error) {
 }
 
 func TestJSON_Convert(t *testing.T) {
+	t.Parallel()
 	data := []struct {
 		title   string
 		x       interface{}
@@ -108,7 +112,9 @@ func TestJSON_Convert(t *testing.T) {
 	for _, d := range data {
 		d := d
 		t.Run(d.title, func(t *testing.T) {
-			a, err := dataeq.JSON.Convert(d.x)
+			t.Parallel()
+			var a interface{}
+			err := dataeq.JSON.Convert(d.x, &a)
 			if d.isError {
 				require.NotNil(t, err)
 				return
@@ -119,7 +125,8 @@ func TestJSON_Convert(t *testing.T) {
 	}
 }
 
-func TestJSON_Equal(t *testing.T) {
+func TestJSON_Equal(t *testing.T) { //nolint:funlen
+	t.Parallel()
 	data := []struct {
 		title   string
 		x       interface{}
@@ -167,6 +174,7 @@ func TestJSON_Equal(t *testing.T) {
 	for _, d := range data {
 		d := d
 		t.Run(d.title, func(t *testing.T) {
+			t.Parallel()
 			f, err := dataeq.JSON.Equal(d.x, d.y)
 			if d.isError {
 				require.NotNil(t, err)
diff --git a/dataeq/doc.go b/dataeq/doc.go
index 767c87b..0e58c30 100644
--- a/dataeq/doc.go
+++ b/dataeq/doc.go
@@ -1,5 +1,5 @@
 // Package dataeq allows to create API to compare two values as the data format such as JSON and YAML.
-// dataeq compare two values by the followin way.
+// dataeq compare two values by the following way.
 //
 // 1. convert value to a byte string by Marshal
 // 2. unmarshal a byte string to `interface{}` by Unmarshal