diff --git a/binding/form_mapping.go b/binding/form_mapping.go
index 91fadcf..87edfbb 100644
--- a/binding/form_mapping.go
+++ b/binding/form_mapping.go
@@ -5,12 +5,13 @@
 package binding
 
 import (
-	"encoding/json"
 	"errors"
 	"reflect"
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/gin-gonic/gin/internal/json"
 )
 
 var errUnknownType = errors.New("Unknown type")
diff --git a/internal/json/json.go b/internal/json/json.go
index 419d35f..480e8bf 100644
--- a/internal/json/json.go
+++ b/internal/json/json.go
@@ -11,6 +11,8 @@ import "encoding/json"
 var (
 	// Marshal is exported by gin/json package.
 	Marshal = json.Marshal
+	// Unmarshal is exported by gin/json package.
+	Unmarshal = json.Unmarshal
 	// MarshalIndent is exported by gin/json package.
 	MarshalIndent = json.MarshalIndent
 	// NewDecoder is exported by gin/json package.
diff --git a/internal/json/jsoniter.go b/internal/json/jsoniter.go
index 2021c53..fabd7b8 100644
--- a/internal/json/jsoniter.go
+++ b/internal/json/jsoniter.go
@@ -12,6 +12,8 @@ var (
 	json = jsoniter.ConfigCompatibleWithStandardLibrary
 	// Marshal is exported by gin/json package.
 	Marshal = json.Marshal
+	// Unmarshal is exported by gin/json package.
+	Unmarshal = json.Unmarshal
 	// MarshalIndent is exported by gin/json package.
 	MarshalIndent = json.MarshalIndent
 	// NewDecoder is exported by gin/json package.