diff --git a/config.go b/config.go
index 3c05e86..337e1d2 100644
--- a/config.go
+++ b/config.go
@@ -6,6 +6,8 @@ import (
 	"net/http"
 	"net/url"
 	"time"
+
+	"github.com/tinh-tinh/tinhtinh/v2/core"
 )
 
 type Config struct {
@@ -27,6 +29,10 @@ type Config struct {
 	ResponseType string
 	// Cancel token
 	CancelToken context.Context
+	// Encoder
+	Encoder core.Encode
+	// Decoder
+	Decoder core.Decode
 }
 
 // GetConfig returns a new *http.Request with the given method, uri and input.
@@ -40,7 +46,7 @@ func (f *Fetch) GetConfig(method string, uri string, input io.Reader) (*http.Req
 		formatUrl = f.Config.BaseUrl
 	}
 
-	formatUrl += IfSlashPrefixString(uri)
+	formatUrl += core.IfSlashPrefixString(uri)
 	if len(f.Config.Params) > 0 {
 		formatUrl += "?" + ParseQuery(f.Config.Params)
 	}
diff --git a/fetch.go b/fetch.go
index 4b1bd4a..e8d31ba 100644
--- a/fetch.go
+++ b/fetch.go
@@ -1,6 +1,7 @@
 package fetch
 
 import (
+	"encoding/json"
 	"io"
 	"net/http"
 )
@@ -15,6 +16,12 @@ type Fetch struct {
 // The configuration includes details like BaseUrl, Headers, Params, and more,
 // which are used to customize HTTP requests made by the Fetch instance.
 func Create(config *Config) *Fetch {
+	if config.Encoder == nil {
+		config.Encoder = json.Marshal
+	}
+	if config.Decoder == nil {
+		config.Decoder = json.Unmarshal
+	}
 	return &Fetch{
 		Config: config,
 	}
@@ -51,7 +58,7 @@ func (f *Fetch) Post(url string, data interface{}, params ...interface{}) *Respo
 		url += "?" + ParseQuery(params)
 	}
 
-	return f.do("POST", url, ParseData(data))
+	return f.do("POST", url, ParseData(data, f.Config.Encoder))
 }
 
 // Patch makes a PATCH request to the specified URL and returns a Response
@@ -70,7 +77,7 @@ func (f *Fetch) Patch(url string, data interface{}, params ...interface{}) *Resp
 		url += "?" + ParseQuery(params)
 	}
 
-	return f.do("PATCH", url, ParseData(data))
+	return f.do("PATCH", url, ParseData(data, f.Config.Encoder))
 }
 
 // Put makes a PUT request to the specified URL and returns a Response
@@ -89,7 +96,7 @@ func (f *Fetch) Put(url string, data interface{}, params ...interface{}) *Respon
 		url += "?" + ParseQuery(params)
 	}
 
-	return f.do("PUT", url, ParseData(data))
+	return f.do("PUT", url, ParseData(data, f.Config.Encoder))
 }
 
 // Delete makes a DELETE request to the specified URL and returns a Response
@@ -133,7 +140,9 @@ func (f *Fetch) do(method string, uri string, input io.Reader) *Response {
 		client.Timeout = f.Config.Timeout
 	}
 
-	response := &Response{}
+	response := &Response{
+		decoder: f.Config.Decoder,
+	}
 	resp, err := client.Do(req)
 	if err != nil {
 		response.Error = err
diff --git a/response.go b/response.go
index 5459d47..eaa2f63 100644
--- a/response.go
+++ b/response.go
@@ -1,19 +1,22 @@
 package fetch
 
-import "encoding/json"
+import (
+	"github.com/tinh-tinh/tinhtinh/v2/core"
+)
 
 type Response struct {
 	Data       []byte
 	Status     int
 	StatusText string
 	Error      error
+	decoder    core.Decode
 }
 
 // Format deserializes the response data into the given model. If the model is nil, the method does nothing.
 // If the deserialization fails, the error is stored in the Response instance.
 func (r *Response) Format(model interface{}) *Response {
 	if model != nil {
-		err := json.Unmarshal(r.Data, model)
+		err := r.decoder(r.Data, model)
 		if err != nil {
 			r.Error = err
 		}
diff --git a/response_test.go b/response_test.go
index 914f35e..0aa3767 100644
--- a/response_test.go
+++ b/response_test.go
@@ -27,6 +27,7 @@ func Test_Schema(t *testing.T) {
 	res := instance.Get("comments", &QueryComment{
 		PostID: 1,
 	}).Format(&comments)
+
 	require.Nil(t, res.Error)
 	require.Equal(t, 200, res.Status)
 	if len(comments) > 0 {
diff --git a/utils.go b/utils.go
index 69ee503..fd6a686 100644
--- a/utils.go
+++ b/utils.go
@@ -1,13 +1,14 @@
 package fetch
 
 import (
-	"encoding/json"
 	"fmt"
 	"io"
 	"log"
 	"reflect"
 	"strconv"
 	"strings"
+
+	"github.com/tinh-tinh/tinhtinh/v2/core"
 )
 
 // ParseQuery takes an interface{} argument and returns a string representing
@@ -99,34 +100,13 @@ func ParseQuery(queryVal interface{}) string {
 // containing the JSON data. If the input data is nil, the function returns nil.
 // If the serialization fails, the function panics. The returned io.Reader can
 // be used to read the JSON data as a stream.
-func ParseData(data interface{}) io.Reader {
+func ParseData(data interface{}, encoder core.Encode) io.Reader {
 	if data == nil {
 		return nil
 	}
-	buffer, err := json.Marshal(data)
+	buffer, err := encoder(data)
 	if err != nil {
 		panic(err)
 	}
 	return strings.NewReader(string(buffer))
 }
-
-// IfSlashPrefixString trims a trailing slash from the string if present,
-// and ensures that the resulting string has a leading slash. If the input
-// string is empty, it returns the empty string. The function formats the
-// string using the ToFormat function before returning it.
-func IfSlashPrefixString(s string) string {
-	if s == "" {
-		return s
-	}
-	s = strings.TrimSuffix(s, "/")
-	if strings.HasPrefix(s, "/") {
-		return ToFormat(s)
-	}
-	return "/" + ToFormat(s)
-}
-
-// ToFormat takes a string and returns a formatted string. The string is
-// converted to lowercase and spaces are removed.
-func ToFormat(s string) string {
-	return strings.ReplaceAll(s, " ", "")
-}
diff --git a/utils_test.go b/utils_test.go
index f1d84f9..ad46632 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -1,6 +1,7 @@
 package fetch_test
 
 import (
+	"encoding/json"
 	"strings"
 	"testing"
 
@@ -78,10 +79,10 @@ func Test_ParseData(t *testing.T) {
 		Age:  13,
 	}
 
-	str := fetch.ParseData(data)
+	str := fetch.ParseData(data, json.Marshal)
 	reader := strings.NewReader("{\"name\":\"Abc\",\"age\":13}")
 	require.Equal(t, reader, str)
 
-	null := fetch.ParseData(nil)
+	null := fetch.ParseData(nil, json.Marshal)
 	require.Nil(t, null)
 }