diff --git a/gen/decoder.go b/gen/decoder.go
index c01ea38..ea38f2b 100644
--- a/gen/decoder.go
+++ b/gen/decoder.go
@@ -108,25 +108,29 @@ func (g *Generator) genTypeDecoder(t reflect.Type, out string, indent int) error
 		elem := t.Elem()
 		tmpVar := g.uniqueVarName()
 
-		fmt.Fprintln(g.out, ws+"in.Delim('{')")
-		fmt.Fprintln(g.out, ws+"if !in.IsDelim('}') {")
-		fmt.Fprintln(g.out, ws+out+" = make("+g.getType(t)+")")
+		fmt.Fprintln(g.out, ws+"if in.IsNull() {")
+		fmt.Fprintln(g.out, ws+"  in.Skip()")
 		fmt.Fprintln(g.out, ws+"} else {")
-		fmt.Fprintln(g.out, ws+out+" = nil")
+		fmt.Fprintln(g.out, ws+"  in.Delim('{')")
+		fmt.Fprintln(g.out, ws+"  if !in.IsDelim('}') {")
+		fmt.Fprintln(g.out, ws+"  "+out+" = make("+g.getType(t)+")")
+		fmt.Fprintln(g.out, ws+"  } else {")
+		fmt.Fprintln(g.out, ws+"  "+out+" = nil")
+		fmt.Fprintln(g.out, ws+"  }")
+
+		fmt.Fprintln(g.out, ws+"  for !in.IsDelim('}') {")
+		fmt.Fprintln(g.out, ws+"    key := in.String()")
+		fmt.Fprintln(g.out, ws+"    in.WantColon()")
+		fmt.Fprintln(g.out, ws+"    var "+tmpVar+" "+g.getType(elem))
+
+		g.genTypeDecoder(elem, tmpVar, indent+2)
+
+		fmt.Fprintln(g.out, ws+"    ("+out+")[key] = "+tmpVar)
+		fmt.Fprintln(g.out, ws+"    in.WantComma()")
+		fmt.Fprintln(g.out, ws+"  }")
+		fmt.Fprintln(g.out, ws+"  in.Delim('}')")
 		fmt.Fprintln(g.out, ws+"}")
 
-		fmt.Fprintln(g.out, ws+"for !in.IsDelim('}') {")
-		fmt.Fprintln(g.out, ws+"  key := in.String()")
-		fmt.Fprintln(g.out, ws+"  in.WantColon()")
-		fmt.Fprintln(g.out, ws+"  var "+tmpVar+" "+g.getType(elem))
-
-		g.genTypeDecoder(elem, tmpVar, indent+1)
-
-		fmt.Fprintln(g.out, ws+"  ("+out+")[key] = "+tmpVar)
-		fmt.Fprintln(g.out, ws+"  in.WantComma()")
-		fmt.Fprintln(g.out, ws+"}")
-		fmt.Fprintln(g.out, ws+"in.Delim('}')")
-
 	case reflect.Interface:
 		if t.NumMethod() != 0 {
 			return fmt.Errorf("interface type %v not supported: only interface{} is allowed", t)
diff --git a/gen/encoder.go b/gen/encoder.go
index 6228130..d55a4a6 100644
--- a/gen/encoder.go
+++ b/gen/encoder.go
@@ -91,17 +91,22 @@ func (g *Generator) genTypeEncoder(t reflect.Type, in string, indent int) error
 		}
 		tmpVar := g.uniqueVarName()
 
-		fmt.Fprintln(g.out, ws+"out.RawByte('{')")
-		fmt.Fprintln(g.out, ws+tmpVar+"_first := true")
-		fmt.Fprintln(g.out, ws+"for "+tmpVar+"_name, "+tmpVar+"_value := range "+in+" {")
-		fmt.Fprintln(g.out, ws+"  if !"+tmpVar+"_first { out.RawByte(',') }")
-		fmt.Fprintln(g.out, ws+"  "+tmpVar+"_first = false")
-		fmt.Fprintln(g.out, ws+"  out.String("+tmpVar+"_name)")
+		fmt.Fprintln(g.out, ws+"if "+in+" == nil {")
+		fmt.Fprintln(g.out, ws+"  out.RawString(`null`)")
+		fmt.Fprintln(g.out, ws+"} else {")
+		fmt.Fprintln(g.out, ws+"  out.RawByte('{')")
+		fmt.Fprintln(g.out, ws+"  "+tmpVar+"_first := true")
+		fmt.Fprintln(g.out, ws+"  for "+tmpVar+"_name, "+tmpVar+"_value := range "+in+" {")
+		fmt.Fprintln(g.out, ws+"    if !"+tmpVar+"_first { out.RawByte(',') }")
+		fmt.Fprintln(g.out, ws+"    "+tmpVar+"_first = false")
+		fmt.Fprintln(g.out, ws+"    out.String("+tmpVar+"_name)")
+		fmt.Fprintln(g.out, ws+"    out.RawByte(':')")
 
-		g.genTypeEncoder(t.Elem(), tmpVar+"_value", indent+1)
+		g.genTypeEncoder(t.Elem(), tmpVar+"_value", indent+2)
 
+		fmt.Fprintln(g.out, ws+"  }")
+		fmt.Fprintln(g.out, ws+"  out.RawByte('}')")
 		fmt.Fprintln(g.out, ws+"}")
-		fmt.Fprintln(g.out, ws+"out.RawByte('}')")
 
 	case reflect.Interface:
 		if t.NumMethod() != 0 {
diff --git a/tests/basic_test.go b/tests/basic_test.go
index 075f148..4231eea 100644
--- a/tests/basic_test.go
+++ b/tests/basic_test.go
@@ -29,6 +29,7 @@ var testCases = []struct {
 	{&stdMarshalerValue, stdMarshalerString},
 	{&unexportedStructValue, unexportedStructString},
 	{&excludedFieldValue, excludedFieldString},
+	{&mapsValue, mapsString},
 }
 
 func TestMarshal(t *testing.T) {
@@ -56,7 +57,7 @@ func TestUnmarshal(t *testing.T) {
 		}
 
 		if !reflect.DeepEqual(v, test.Decoded) {
-			t.Errorf("[%d, %T] UnmarshalJSON(): got \n%+v\n\t\t want \n%+v", i, test.Decoded, v, test.Encoded)
+			t.Errorf("[%d, %T] UnmarshalJSON(): got \n%+v\n\t\t want \n%+v", i, test.Decoded, v, test.Decoded)
 		}
 	}
 }
diff --git a/tests/data.go b/tests/data.go
index 9f1ef81..f284720 100644
--- a/tests/data.go
+++ b/tests/data.go
@@ -373,3 +373,20 @@ var excludedFieldValue = ExcludedField{
 	DoNotProcess: false,
 }
 var excludedFieldString = `{"process":true}`
+
+type Maps struct {
+	Map          map[string]string
+	InterfaceMap map[string]interface{}
+	NilMap       map[string]string
+}
+
+var mapsValue = Maps{
+	Map:          map[string]string{"A": "b"}, // only one item since map iteration is randomized
+	InterfaceMap: map[string]interface{}{"G": 1},
+}
+
+var mapsString = `{` +
+	`"Map":{"A":"b"},` +
+	`"InterfaceMap":{"G":1},` +
+	`"NilMap":null` +
+	`}`