Get started with Baileys

Build your first WhatsApp bot with Baileys in minutes. Learn to connect, handle events, save sessions, and send your first message step by step.

This guide walks you through creating a minimal Baileys application that connects to WhatsApp, persists your session, listens for incoming messages, and replies to them. By the end you will have a working bot you can extend with your own logic.

Baileys is an unofficial library and is not affiliated with WhatsApp. Use it responsibly and in accordance with WhatsApp’s Terms of Service. The maintainers do not condone bulk messaging, spam, or stalkerware.

Complete example

The steps below build up to this complete working script. You can use it as a starting point for your own project.

import makeWASocket, { DisconnectReason, useMultiFileAuthState } from '@whiskeysockets/baileys'
import { Boom } from '@hapi/boom'
import qrcode from 'qrcode-terminal'

async function connectToWhatsApp() {
    const { state, saveCreds } = await useMultiFileAuthState('auth_info_baileys')

    const sock = makeWASocket({
        auth: state
    })

    sock.ev.on('connection.update', (update) => {
        const { connection, lastDisconnect, qr } = update
        if (qr) {
            qrcode.generate(qr, { small: true })
        }
        if (connection === 'close') {
            const shouldReconnect =
                (lastDisconnect?.error as Boom)?.output?.statusCode !== DisconnectReason.loggedOut
            console.log('connection closed due to', lastDisconnect?.error, ', reconnecting:', shouldReconnect)
            if (shouldReconnect) {
                connectToWhatsApp()
            }
        } else if (connection === 'open') {
            console.log('opened connection')
        }
    })

    sock.ev.on('messages.upsert', async (event) => {
        for (const m of event.messages) {
            console.log(JSON.stringify(m, undefined, 2))

            console.log('replying to', m.key.remoteJid)
            await sock.sendMessage(m.key.remoteJid!, { text: 'Hello from Baileys!' })
        }
    })

    // Save credentials whenever they are updated
    sock.ev.on('creds.update', saveCreds)
}

connectToWhatsApp()

---

Step-by-step walkthrough

1. Install Baileys

   Add Baileys and its @hapi/boom peer to your project. @hapi/boom is a direct dependency of Baileys and is used to inspect disconnect error codes.

   npm

   npm install @whiskeysockets/baileys @hapi/boom
   

   Make sure you are running Node.js 20.0.0 or later. Installation will fail otherwise.

2. Set up auth state

   Baileys requires an auth state object to manage your session credentials and Signal Protocol keys. The built-in useMultiFileAuthState utility saves everything to a local folder.

   import makeWASocket, { useMultiFileAuthState } from '@whiskeysockets/baileys'
   
   const { state, saveCreds } = await useMultiFileAuthState('auth_info_baileys')
   

   state holds the current credentials and keys. saveCreds is a callback you will pass to the creds.update event so the session is written to disk whenever it changes.

   The folder name (auth_info_baileys in this example) can be any path you choose. Store it outside your source tree and add it to .gitignore — it contains long-lived cryptographic keys for your WhatsApp account.

3. Create the socket

   Create a socket by calling makeWASocket with your auth state. Listen for the qr field on connection.update and render it yourself — printQRInTerminal is deprecated.

   import qrcode from 'qrcode-terminal'
   
   const sock = makeWASocket({
       auth: state
   })
   
   sock.ev.on('connection.update', ({ qr }) => {
       if (qr) qrcode.generate(qr, { small: true })
   })
   

   When you run this for the first time, a QR code appears in your terminal. Open WhatsApp on your phone, go to Settings → Linked devices → Link a device, and scan the code. On subsequent runs, the saved credentials are reused and no QR code is shown.

4. Handle connection updates

   Listen to connection.update to react when the connection opens, closes, or encounters an error. The reconnect logic below restarts the socket automatically — unless you were explicitly logged out.

   import { DisconnectReason } from '@whiskeysockets/baileys'
   import { Boom } from '@hapi/boom'
   
   sock.ev.on('connection.update', (update) => {
       const { connection, lastDisconnect } = update
       if (connection === 'close') {
           const shouldReconnect =
               (lastDisconnect?.error as Boom)?.output?.statusCode !== DisconnectReason.loggedOut
           console.log('connection closed due to', lastDisconnect?.error, ', reconnecting:', shouldReconnect)
           if (shouldReconnect) {
               connectToWhatsApp()
           }
       } else if (connection === 'open') {
           console.log('opened connection')
       }
   })
   

   DisconnectReason.loggedOut means your session was revoked (for example, you removed the linked device in the WhatsApp app). In that case, delete the auth folder and re-scan a QR code.

5. Listen for incoming messages

   The messages.upsert event fires whenever new messages arrive. Iterate over event.messages to handle each one.

   sock.ev.on('messages.upsert', async (event) => {
       for (const m of event.messages) {
           console.log(JSON.stringify(m, undefined, 2))
   
           console.log('replying to', m.key.remoteJid)
           await sock.sendMessage(m.key.remoteJid!, { text: 'Hello from Baileys!' })
       }
   })
   

   m.key.remoteJid is the WhatsApp ID (JID) of the chat the message came from — a phone number for individual chats, or a group ID for group chats. Pass it as the first argument to sock.sendMessage to reply.

6. Save credentials on update

   Register the saveCreds callback on the creds.update event. Baileys calls this whenever your session credentials change — for example, after the initial QR scan or after Signal session keys rotate.

   sock.ev.on('creds.update', saveCreds)
   

   If you skip this step, your session will not be saved and you will need to scan the QR code again on every restart.

What’s next

Now that you have a working connection, explore the rest of the documentation to learn what Baileys can do:

Authentication

Use a pairing code instead of a QR code, or learn how to manage sessions in a database.

Sending messages

Send text, images, video, audio, polls, reactions, and more.

Events

See the full list of events Baileys emits and what data each one carries.

Groups

Create and manage groups, handle join requests, and configure ephemeral messages.