Baileys uses the EventEmitter pattern to notify you about incoming messages, connection changes, and credential updates. You listen to these events to build your bot’s functionality.
Key Events
You can find all available events in the BaileysEventMap type definition.
messages.upsert
Fired when new messages arrive or are sent from another device.
sock.ev.on('messages.upsert', ({ messages, type }) => {
console.log('got messages', messages)
for (const msg of messages) {
if (!msg.message) continue
const text = msg.message.conversation || msg.message.extendedTextMessage?.text
console.log('Message text:', text)
// Reply to the message
if (!msg.key.fromMe) {
await sock.sendMessage(msg.key.remoteJid!, { text: 'Hello!' })
}
}
})
The type field indicates whether this is a 'notify' (new message) or 'append' (history sync) event.
connection.update
Handles connection state changes, QR code generation, and disconnections.
sock.ev.on('connection.update', (update) => {
const { connection, lastDisconnect, qr } = 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')
}
if (qr) {
console.log('QR Code:', qr)
}
})
Always check the disconnect reason before reconnecting. If the status code is DisconnectReason.loggedOut, do not reconnect automatically.
creds.update
Fired when authentication credentials are updated. You must save these credentials to maintain your session.
import makeWASocket, { useMultiFileAuthState } from '@whiskeysockets/baileys'
const { state, saveCreds } = await useMultiFileAuthState('auth_info_baileys')
const sock = makeWASocket({ auth: state })
sock.ev.on('creds.update', saveCreds)
Credentials update whenever signal sessions change (on send/receive). Not saving them will cause message delivery failures.
Processing Events Efficiently
You can use sock.ev.process() to batch-process multiple events at once:
sock.ev.process(async (events) => {
if (events['connection.update']) {
const update = events['connection.update']
console.log('connection update', update)
}
if (events['creds.update']) {
await saveCreds()
}
if (events['messages.upsert']) {
const { messages } = events['messages.upsert']
for (const msg of messages) {
console.log('new message', msg)
}
}
})
Other Common Events
messages.update
Fired when messages are edited, deleted, or status changes (delivered, read).
sock.ev.on('messages.update', (updates) => {
for (const { key, update } of updates) {
console.log('message updated:', key.id, update)
}
})
chats.update
Fired when chat metadata changes (unread count, last message timestamp).
sock.ev.on('chats.update', (updates) => {
console.log('chats updated', updates)
})
sock.ev.on('contacts.update', async (updates) => {
for (const contact of updates) {
if (typeof contact.imgUrl !== 'undefined') {
const newUrl = contact.imgUrl === null
? null
: await sock.profilePictureUrl(contact.id!).catch(() => null)
console.log('contact has a new profile pic:', newUrl)
}
}
})
presence.update
Fired when a contact’s presence changes (online, typing, recording).
sock.ev.on('presence.update', (update) => {
console.log('presence update:', update)
})
// Subscribe to presence updates for a specific chat
await sock.presenceSubscribe(jid)
Complete Example
Set up authentication
import makeWASocket, { DisconnectReason, useMultiFileAuthState } from '@whiskeysockets/baileys'
import { Boom } from '@hapi/boom'
const { state, saveCreds } = await useMultiFileAuthState('auth_info_baileys')
Create the socket
const sock = makeWASocket({
auth: state
})
Handle events
sock.ev.on('connection.update', (update) => {
const { connection, lastDisconnect } = update
if (connection === 'close') {
const shouldReconnect = (lastDisconnect.error as Boom)?.output?.statusCode !== DisconnectReason.loggedOut
if (shouldReconnect) {
connectToWhatsApp()
}
} else if (connection === 'open') {
console.log('opened connection')
}
})
sock.ev.on('messages.upsert', async ({ messages }) => {
for (const msg of messages) {
console.log('received message:', msg)
if (!msg.key.fromMe && msg.message) {
await sock.sendMessage(msg.key.remoteJid!, { text: 'Hello!' })
}
}
})
sock.ev.on('creds.update', saveCreds)