diff --git a/binding/json.go b/binding/json.go
index 310922c1..da92cb9d 100644
--- a/binding/json.go
+++ b/binding/json.go
@@ -17,6 +17,10 @@ import (
 // interface{} as a Number instead of as a float64.
 var EnableDecoderUseNumber = false
 
+// EnableDecoderKnownFieldsOnly is used to toggle DisallowUnknownFields
+// which is disabled by default
+var EnableDecoderKnownFieldsOnly = false
+
 type jsonBinding struct{}
 
 func (jsonBinding) Name() string {
@@ -36,6 +40,9 @@ func decodeJSON(r io.Reader, obj interface{}) error {
 	if EnableDecoderUseNumber {
 		decoder.UseNumber()
 	}
+	if EnableDecoderKnownFieldsOnly {
+		decoder.DisallowUnknownFields()
+	}
 	if err := decoder.Decode(obj); err != nil {
 		return err
 	}