Common Errors in WhatsApp Bot Deployment and How to Fix Them

Building a WhatsApp bot with Baileys is exciting. Deploying it on a server is where most developers start facing strange errors. The bot works perfectly on a local computer, but once uploaded to hosting, problems begin. This guide explains the most common errors and their practical fixes.

1) Application Error After Deploy

This usually happens when the start script is missing in package.json.

"scripts": {
  "start": "node index.js"
}

Make sure your main file name matches.

2) Module Not Found Error

If Heroku or VPS shows Cannot find module, it means dependencies are not listed in package.json.

Run this before uploading:

npm install --save @whiskeysockets/baileys

3) Session Expired / Pairing Again and Again

This happens when the session folder is not saved or gets deleted on restart. Always store session files properly and avoid clearing them.

4) QR Code Not Showing in Logs

Make sure you are printing QR in terminal using qrcode-terminal and checking live logs of your hosting.

5) Bot Stops After Some Time

On VPS, use PM2:

pm2 start index.js --name bot
pm2 save
pm2 startup

6) WhatsApp Ban Risk

• Avoid spam replies
• Add delay between messages
• Do not auto message unknown users

7) Port or Build Errors

Do not hardcode ports. Let hosting decide environment port automatically.

8) Slow Response or Crashes

Use proper error handling and avoid heavy loops in message listeners.

Conclusion

Most deployment errors are small mistakes in configuration. Once you understand these common problems, your WhatsApp bot can run smoothly 24/7 without interruption.