diff --git a/server/server_test.go b/server/server_test.go
index e2800cf4c5..5803334f4e 100644
--- a/server/server_test.go
+++ b/server/server_test.go
@@ -3431,7 +3431,7 @@ func TestUnversionedPost(t *testing.T) {
 	f.reset()
 	f.server.Handler.ServeHTTP(f.recorder, post())
 
-	expected := `{"agg":6}`
+	expected := "{\"agg\":6}\n"
 	if f.recorder.Code != 200 || f.recorder.Body.String() != expected {
 		t.Fatalf(`Expected HTTP 200 / %v but got: %v`, expected, f.recorder)
 	}
diff --git a/server/writer/writer.go b/server/writer/writer.go
index 3582fa90aa..e0131beeca 100644
--- a/server/writer/writer.go
+++ b/server/writer/writer.go
@@ -58,27 +58,18 @@ func Error(w http.ResponseWriter, status int, err *types.ErrorV1) {
 // JSON writes a response with the specified status code and object. The object
 // will be JSON serialized.
 func JSON(w http.ResponseWriter, code int, v interface{}, pretty bool) {
-
-	var bs []byte
-	var err error
-
+	enc := json.NewEncoder(w)
 	if pretty {
-		bs, err = json.MarshalIndent(v, "", "  ")
-	} else {
-		bs, err = json.Marshal(v)
+		enc.SetIndent("", "  ")
 	}
 
-	if err != nil {
+	w.Header().Add("Content-Type", "application/json")
+	w.WriteHeader(code)
+
+	if err := enc.Encode(v); err != nil {
 		ErrorAuto(w, err)
 		return
 	}
-	headers := w.Header()
-	headers.Add("Content-Type", "application/json")
-	Bytes(w, code, bs)
-
-	if pretty {
-		_, _ = w.Write([]byte("\n"))
-	}
 }
 
 // Bytes writes a response with the specified status code and bytes.
diff --git a/test/e2e/distributedtracing/distributedtracing_test.go b/test/e2e/distributedtracing/distributedtracing_test.go
index 8509b1b678..73d795b45a 100644
--- a/test/e2e/distributedtracing/distributedtracing_test.go
+++ b/test/e2e/distributedtracing/distributedtracing_test.go
@@ -77,7 +77,7 @@ func TestServerSpan(t *testing.T) {
 			attribute.Int("http.status_code", 200),
 			attribute.String("http.target", "/v0/data"),
 			attribute.String("http.user_agent", "Go-http-client/1.1"),
-			attribute.Int("http.wrote_bytes", 2),
+			attribute.Int("http.wrote_bytes", 3),
 			attribute.String("net.transport", "ip_tcp"),
 		}
 		compareSpanAttributes(t, expected, attribute.NewSet(spans[0].Attributes...))
@@ -111,7 +111,7 @@ func TestServerSpan(t *testing.T) {
 			attribute.Int("http.status_code", 200),
 			attribute.String("http.target", "/v1/data"),
 			attribute.String("http.user_agent", "Go-http-client/1.1"),
-			attribute.Int("http.wrote_bytes", 66),
+			attribute.Int("http.wrote_bytes", 67),
 			attribute.String("net.transport", "ip_tcp"),
 		}
 		compareSpanAttributes(t, expected, attribute.NewSet(spans[0].Attributes...))