Migrating from pyTelegramBotAPI

Let’s show another echobot from their README:

import telebot

bot = telebot.TeleBot("TOKEN")

@bot.message_handler(commands=['start'])
def send_welcome(message):
    bot.reply_to(message, "Howdy, how are you doing?")

@bot.message_handler(func=lambda m: True)
def echo_all(message):
    bot.reply_to(message, message.text)

bot.polling()

Now we rewrite it to use Telethon:

from telethon import TelegramClient, events

bot = TelegramClient('bot', 11111, 'a1b2c3d4').start(bot_token='TOKEN')

@bot.on(events.NewMessage(pattern='/start'))
async def send_welcome(event):
    await event.reply('Howdy, how are you doing?')

@bot.on(events.NewMessage)
async def echo_all(event):
    await event.reply(event.text)

bot.run_until_disconnected()

Key differences:

• Instead of doing bot.reply_to(message), we can do event.reply. Note that the event behaves just like their message.
• Telethon also supports func=lambda m: True, but it’s not necessary.