Facebook Messenger Bot Development Guide

Overview#

Facebook Messenger bots allow you to create interactive experiences for your customers. This guide covers everything from setup to advanced features.

Prerequisites#

• Facebook Developer Account
• Node.js and npm
• ngrok for local development

Step 1: Create Facebook App#

1. Go to Facebook Developers
2. Create a new app
3. Add Messenger product
4. Generate access token

Step 2: Setup Webhook#

const express = require('express');
const app = express();

app.get('/webhook', (req, res) => {
  const VERIFY_TOKEN = process.env.VERIFY_TOKEN;
  const mode = req.query['hub.mode'];
  const token = req.query['hub.verify_token'];
  const challenge = req.query['hub.challenge'];

  if (mode && token) {
    if (mode === 'subscribe' && token === VERIFY_TOKEN) {
      res.status(200).send(challenge);
    } else {
      res.sendStatus(403);
    }
  }
});

Step 3: Handle Messages#

app.post('/webhook', (req, res) => {
  const body = req.body;

  if (body.object === 'page') {
    body.entry.forEach(entry => {
      const webhookEvent = entry.messaging[0];
      
      if (webhookEvent.message) {
        handleMessage(webhookEvent);
      }
    });
    
    res.status(200).send('EVENT_RECEIVED');
  } else {
    res.sendStatus(404);
  }
});

Advanced Features#

• Quick Replies
• Persistent Menu
• Typing Indicators
• Rich Media

Production Facebook Messenger Setup for Nepal#

Deploying Messenger bots for Kathmandu retail stores involves distinct regional practices:

• Deposit Collection via QR: Automate prompt dispatch of eSewa and Fonepay QR payment requests inside the chat to lock in orders and reduce COD cancellations.
• Courier API Dispatch: Connect approved Messenger orders directly to Pathao or Nepal Can Move delivery creation APIs via webhooks.
• Transparent Pricing in NPR: Always state prices in NPR upfront in welcome flows to filter casual window shoppers from serious buyers.

Conclusion#

You now have a fully functional Facebook Messenger bot!