diff --git a/atcheck-websocket/server.js b/atcheck-websocket/server.js
index e3e9b1f..51ccafd 100644
--- a/atcheck-websocket/server.js
+++ b/atcheck-websocket/server.js
@@ -1,5 +1,6 @@
 const WebSocket = require('ws');
 var https = require('https');
+const fs = require('fs');
 
 var websocket_port = 8888;
 const wss = new WebSocket.Server({port: websocket_port});