diff --git a/api.go b/api.go
index c694119bd..9456d81b0 100644
--- a/api.go
+++ b/api.go
@@ -22,16 +22,48 @@ import (
  
  // Config is a combination of sonic/encoder.Options and sonic/decoder.Options
  type Config struct {
+    // EscapeHTML indicates encoder to escape all HTML characters 
+    // after serializing into JSON (see https://pkg.go.dev/encoding/json#HTMLEscape).
+    // WARNING: This hurts performance A LOT, USE WITH CARE.
     EscapeHTML                    bool
+
+    // SortMapKeys indicates encoder that the keys of a map needs to be sorted 
+    // before serializing into JSON.
+    // WARNING: This hurts performance A LOT, USE WITH CARE.
     SortMapKeys                   bool
+
+    // CompactMarshaler indicates encoder that the output JSON from json.Marshaler 
+    // is always compact and needs no validation 
     CompactMarshaler              bool
+
+    // NoQuoteTextMarshaler indicates encoder that the output text from encoding.TextMarshaler 
+    // is always escaped string and needs no quoting
     NoQuoteTextMarshaler          bool
+
+    // NoNullSliceOrMap indicates encoder that all empty Array or Object are encoded as '[]' or '{}',
+    // instead of 'null'
+    NoNullSliceOrMap              bool
+
+    // UseInt64 indicates decoder to unmarshal an integer into an interface{} as an
+    // int64 instead of as a float64.
     UseInt64                      bool
+
+    // UseNumber indicates decoder to unmarshal a number into an interface{} as a
+    // json.Number instead of as a float64.
     UseNumber                     bool
+
+    // UseUnicodeErrors indicates decoder to return an error when encounter invalid
+    // UTF-8 escape sequences.
     UseUnicodeErrors              bool
+
+    // DisallowUnknownFields indicates decoder to return an error when the destination
+    // is a struct and the input contains object keys which do not match any
+    // non-ignored, exported fields in the destination.
     DisallowUnknownFields         bool
+
+    // CopyString indicates decoder to decode string values by copying instead of referring.
     CopyString                    bool
-    NoNullSliceOrMap              bool
+
  }
  
  var (
@@ -53,7 +85,7 @@ import (
  )
  
  
- // API a binding of specific config.
+ // API is a binding of specific config.
  // This interface is inspired by github.com/json-iterator/go,
  // and has same behaviors under equavilent config.
  type API interface {
diff --git a/decoder/decoder.go b/decoder/decoder.go
index d59473e9a..3b7b5e0f4 100644
--- a/decoder/decoder.go
+++ b/decoder/decoder.go
@@ -48,7 +48,7 @@ const (
 )
 
 func (self *Decoder) SetOptions(opts Options) {
-    if (opts & 1<<_F_use_number != 0) && (opts & 1<<_F_use_int64 != 0) {
+    if (opts & OptionUseNumber != 0) && (opts & OptionUseInt64 != 0) {
         panic("can't set OptionUseInt64 and OptionUseNumber both!")
     }
     self.f = uint64(opts)
@@ -107,34 +107,34 @@ func (self *Decoder) Decode(val interface{}) error {
     return err
 }
 
-// UseInt64 causes the Decoder to unmarshal an integer into an interface{} as an
+// UseInt64 indicates the Decoder to unmarshal an integer into an interface{} as an
 // int64 instead of as a float64.
 func (self *Decoder) UseInt64() {
     self.f  |= 1 << _F_use_int64
     self.f &^= 1 << _F_use_number
 }
 
-// UseNumber causes the Decoder to unmarshal a number into an interface{} as a
+// UseNumber indicates the Decoder to unmarshal a number into an interface{} as a
 // json.Number instead of as a float64.
 func (self *Decoder) UseNumber() {
     self.f &^= 1 << _F_use_int64
     self.f  |= 1 << _F_use_number
 }
 
-// UseUnicodeErrors causes the Decoder to return an error when encounter invalid
+// UseUnicodeErrors indicates the Decoder to return an error when encounter invalid
 // UTF-8 escape sequences.
 func (self *Decoder) UseUnicodeErrors() {
     self.f |= 1 << _F_disable_urc
 }
 
-// DisallowUnknownFields causes the Decoder to return an error when the destination
+// DisallowUnknownFields indicates the Decoder to return an error when the destination
 // is a struct and the input contains object keys which do not match any
 // non-ignored, exported fields in the destination.
 func (self *Decoder) DisallowUnknownFields() {
     self.f |= 1 << _F_disable_unknown
 }
 
-// CopyString causes the Decoder to decode string values by copying instead of referring.
+// CopyString indicates the Decoder to decode string values by copying instead of referring.
 func (self *Decoder) CopyString() {
     self.f |= 1 << _F_copy_string
 }
diff --git a/decoder/decoder_test.go b/decoder/decoder_test.go
index 6c1f67fb0..6a0f48779 100644
--- a/decoder/decoder_test.go
+++ b/decoder/decoder_test.go
@@ -275,6 +275,15 @@ func TestDecoder_Binding(t *testing.T) {
     spew.Dump(v)
 }
 
+func TestDecoder_SetOption(t *testing.T) {
+    var v interface{}
+    d := NewDecoder("123")
+    d.SetOptions(OptionUseInt64)
+    err := d.Decode(&v)
+    assert.NoError(t, err)
+    assert.Equal(t, v, int64(123))
+}
+
 func TestDecoder_MapWithIndirectElement(t *testing.T) {
     var v map[string]struct { A [129]byte }
     _, err := decode(`{"":{"A":[1,2,3,4,5]}}`, &v, false)