telegraf + webhook + ngrok + express

bot.js

import bot from './setup-bot'

bot.hears('Hi', ctx => {
  ctx.reply('Hi there!')
})

export default bot

server.js

import ngrok from 'ngrok';
import express from 'express';
import bot from './bot'

const app = express();
const port = parseInt(process.env.PORT) || 8080;

// Without top-level await
const launch = async () => {
  try {
    let url = 'https://yourdomain.com/';
    // Use temporary url on development mode
    if (process.env.NODE_ENV !== 'production') {
      url = await ngrok.connect({
        authToken: '...', // Your ngrok auth token
        addr: port
      });
      console.log(`Temporary url: ${url}`);
    }
    app.use(await bot.createWebhook({
      domain: url
    }));
  } catch (e) {
    console.error(e)
  }
};

// Send POST request to: https://temporary-url.ngrok.io/my-post-route
app.post('/my-post-route', async (req, res) => {
  res.send('Hi there!')
});

launch();
app.listen(port);

setup-bot.js

import { Telegraf, session } from 'telegraf';

const bot = new Telegraf(process.env.BOT_TOKEN)

bot.use(session({ defaultSession: () => ({}) })

export default bot