diff --git a/envelopes.go b/envelopes.go
index 967b43e..7bcacac 100644
--- a/envelopes.go
+++ b/envelopes.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"strconv"
 
 	"github.com/mailru/easyjson"
 	jwriter "github.com/mailru/easyjson/jwriter"
@@ -190,7 +191,9 @@ func (v CountEnvelope) MarshalJSON() ([]byte, error) {
 	w.RawString(`["COUNT",`)
 	w.RawString(`"` + v.SubscriptionID + `"`)
 	if v.Count != nil {
-		w.RawString(fmt.Sprintf(`,{"count":%d}`, *v.Count))
+		w.RawString(`,{"count":`)
+		w.RawString(strconv.FormatInt(*v.Count, 10))
+		w.RawString(`}`)
 	} else {
 		for _, filter := range v.Filters {
 			w.RawString(`,`)
diff --git a/envelopes_test.go b/envelopes_test.go
index 06ed8e3..0f01065 100644
--- a/envelopes_test.go
+++ b/envelopes_test.go
@@ -63,6 +63,19 @@ func TestEoseEnvelopeEncodingAndDecoding(t *testing.T) {
 	}
 }
 
+func TestCountEnvelopeEncodingAndDecoding(t *testing.T) {
+	src := `["COUNT","z",{"count":12}]`
+	var env CountEnvelope
+	json.Unmarshal([]byte(src), &env)
+	if *env.Count != 12 {
+		t.Error("failed to decode COUNT")
+	}
+
+	if res, _ := json.Marshal(env); string(res) != src {
+		t.Errorf("failed to encode COUNT: expected '%s', got '%s'", src, string(res))
+	}
+}
+
 func TestOKEnvelopeEncodingAndDecoding(t *testing.T) {
 	okEnvelopes := []string{
 		`["OK","3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefaaaaa",false,"error: could not connect to the database"]`,