Application Setup

No Bot Token Required

Unlike Discord or Telegram, WhatsApp does not have an official bot API requiring tokens. WWebJS instead uses WhatsApp Web to connect to your personal account. This means:

No need to create a separate bot account
Use your existing WhatsApp account
Full access to all WhatsApp Web features
Authentication happens through QR code scanning

Create Your First Bot

Let's create a simple bot that responds to messages.

Step 1: Create the Main File

Create src/index.js:

const { Client, LocalAuth } = require('whatsapp-web.js')
const qrcode = require('qrcode-terminal')

const client = new Client({
  authStrategy: new LocalAuth(),
})

client.on('qr', qr => {
  console.log('Scan the QR code below with your phone:')
  qrcode.generate(qr, { small: true })
})

client.on('ready', () => {
  console.log('Bot is ready!')
})

client.on('message_create', async message => {
  if (message.body === 'hello') {
    message.reply('Hi there!')
  }
})

client.initialize()

Step 2: Install QR Code Display

For easier QR code scanning:

npm install qrcode-terminal

Step 3: Run Your Bot

npm start

Step 4: Authenticate

Open your terminal where the bot is running
Scan the QR code with your WhatsApp phone
Approve the login request on your phone
Bot is now connected and listening for messages

Authentication Strategies

WWebJS offers different authentication methods:

LocalAuth (Recommended for Development)

Stores session data locally on your machine:

const { LocalAuth } = require('whatsapp-web.js')

const client = new Client({
  authStrategy: new LocalAuth(),
})

Pros: Simple, no external dependencies Cons: Session stored only on that machine

NoAuth

No session storage (logs out each restart):

const client = new Client()

Pros: Fresh login each time Cons: Need to scan QR code every restart

RemoteAuth

Stores session on a server (advanced):

For production deployments where you need persistent sessions across machines.

Handle Different Message Types

Respond to different message types:

client.on('message_create', async message => {
  // Check message type
  if (message.type === 'chat') {
    message.reply('Text message received')
  } else if (message.type === 'image') {
    message.reply('Image received')
  } else if (message.type === 'video') {
    message.reply('Video received')
  } else if (message.type === 'audio') {
    message.reply('Audio received')
  }
})

Respond to Specific Users

Filter messages from certain users:

client.on('message_create', async message => {
  const contact = await message.getContact()

  if (contact.name === 'Important Person') {
    message.reply('Hi! Thanks for messaging')
  }
})

Handle Errors Gracefully

Always include error handling:

client.on('error', error => {
  console.error('Client error:', error)
})

client.on('disconnected', reason => {
  console.log('Client disconnected:', reason)
})

process.on('unhandledRejection', error => {
  console.error('Unhandled rejection:', error)
})