diff --git a/enriched_activities.go b/enriched_activities.go
index 5e59f44..83b6f03 100644
--- a/enriched_activities.go
+++ b/enriched_activities.go
@@ -3,6 +3,8 @@ package stream
 import (
 	"encoding/json"
 	"errors"
+	"reflect"
+	"strings"
 
 	"github.com/fatih/structs"
 )
@@ -74,7 +76,20 @@ func (a *EnrichedActivity) UnmarshalJSON(b []byte) error {
 // MarshalJSON encodes the EnrichedActivity to a valid JSON bytes slice. It's required because of
 // the custom JSON fields and time formats.
 func (a EnrichedActivity) MarshalJSON() ([]byte, error) {
-	data := structs.New(a).Map()
+	fields := structs.New(a).Fields()
+	data := make(map[string]interface{}, len(fields))
+	for _, f := range fields {
+		if f.Kind() == reflect.Struct {
+			tag := f.Tag("json")
+			if !strings.HasSuffix(tag, ",omitempty") || !structs.IsZero(f.Value()) {
+				data[strings.TrimSuffix(tag, ",omitempty")] = f.Value()
+			}
+		}
+	}
+	for k, v := range a.Extra {
+		data[k] = v
+	}
+
 	for k, v := range a.Extra {
 		data[k] = v
 	}
diff --git a/types.go b/types.go
index eabb776..2a1e5a4 100644
--- a/types.go
+++ b/types.go
@@ -109,6 +109,19 @@ func (a *Data) decode(data map[string]interface{}) error {
 	return nil
 }
 
+// MarshalJSON encodes data into json.
+func (a Data) MarshalJSON() ([]byte, error) {
+	m := make(map[string]interface{}, len(a.Extra))
+	for k, v := range a.Extra {
+		m[k] = v
+	}
+	result := map[string]interface{}{
+		"id":   a.ID,
+		"data": m,
+	}
+	return json.Marshal(result)
+}
+
 // Rate is the information to be filled if a rate limited response
 type Rate struct {
 	// Limit is the existing limit for the resource
diff --git a/types_test.go b/types_test.go
index d4571e4..477b274 100644
--- a/types_test.go
+++ b/types_test.go
@@ -35,3 +35,16 @@ func TestTimeMarshalUnmarshalJSON(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, st, out)
 }
+
+func TestEnrichedActivityMarshal(t *testing.T) {
+	e := stream.EnrichedActivity{
+		Actor: stream.Data{
+			ID:    "my_id",
+			Extra: map[string]interface{}{"a": 1, "b": "c"},
+		},
+	}
+
+	b, err := json.Marshal(e)
+	require.NoError(t, err)
+	require.JSONEq(t, `{"actor": {"id":"my_id","data":{"a":1,"b":"c"}}}`, string(b))
+}