diff --git a/playground/autocomplete.go b/playground/autocomplete.go
index 022642b..91d6f9b 100644
--- a/playground/autocomplete.go
+++ b/playground/autocomplete.go
@@ -24,11 +24,17 @@ import (
 	"strings"
 
 	"github.com/88250/gulu"
+	"github.com/88250/wide/conf"
 	"github.com/88250/wide/session"
 )
 
 // AutocompleteHandler handles request of code autocompletion.
 func AutocompleteHandler(w http.ResponseWriter, r *http.Request) {
+	if conf.Wide.ReadOnly {
+		http.Error(w, "Forbidden", http.StatusForbidden)
+		return
+	}
+
 	var args map[string]interface{}
 	if err := json.NewDecoder(r.Body).Decode(&args); err != nil {
 		logger.Error(err)