Posted on Jan 28, 2021 • Updated on Sep 4, 2021

Checking if a phone number is on Telegram, using TDLib and Python

#python #tutorial #telegram #api

This may come in handy if you plan to migrate, for example, an existing WhatsApp group. A good number of users that have already migrated may be a convincing argument to promote such change, specially in communities where Telegram wasn't that well known so far.

In this tutorial we'll be using the Telegram Database Library (or TDLib), which lets you build your own Telegram clients. Happily, there is a nice python wrapper for it.

1. Setting up

The first thing is registering a new Telegram Application.

Once that we have both api_id and api_hash, we need to get python-telegram. Make sure you use Python 3.6+.

python3 -m pip install python-telegram

2. Calling the API

We are ready to instantiate the client.

from telegram.client import Telegram

tg = Telegram(
    api_id='YOUR API ID',
    api_hash='YOUR API HASH',
    phone='+575555555555',
    database_encryption_key='changeme1234',
)

tg.login()

A prompt will wait for us to enter a verification code, which will be sent to our telegram account.

Note: database_encryption_key is just a string TDLib needs in order to encrypt and decrypt the local database. If you're going to build a real Telegram client, make sure this key is a strong one (just like a password). For this exercise it may not be worth coming up with a super secure key, but this is up to you.

The Telegram class has some TDLib methods available, like login(), send_message(), and a few more. For any other we need to use call_method().

In order to check whether a phone number is using Telegram or not, we need to add it as a contact. importContacts() is what we are looking for. It let us add new contacts just by their phone numbers, though you can also specify things like first_name, last_name, and others.

response = tg.call_method('importContacts', {
    'contacts': [
        {'phone_number': '+57 555 123 4567'},
    ]
})

response.wait()

user_ids = response.update['user_ids']

If a number is not currently on the platform, it will return 0 as its user id.

if user_ids[0] == 0:
    print('This contact is NOT using Telegram.')
else:
    print(f'¡This contact({user_ids[0]}) uses Telegram!')

3. Cleaning

Time to remove those testing contacts.

tg.call_method('removeContacts', {'user_ids': user_ids})

And that's it. Hope you enjoyed my first tutorial 🧪

Happy hacking!

Top comments (12)

Usman Ali • Jul 26 '21

TypeError Traceback (most recent call last)
in ()
12 response.wait()
13 counter += 1
---> 14 user_ids = response.update['user_ids']
15 if user_ids[0] == 0:
16 print('This contact is NOT using Telegram.'+value)

TypeError: 'NoneType' object is not subscriptable

After Running this code i check only 1000 number and after this this code stop working. Because number error. when i change phone number this code again start working perfectly. Can you please guide me who i can avoid this error?

!python3 -m pip install python-telegram
from google.colab import drive
drive.mount('/content/drive')

import pandas as pd
from telegram.client import Telegram

tg = Telegram(
api_id='Write Your Api',
api_hash='Write Your Hash',
phone='Write you Number',
database_encryption_key='hisunny1',
)

tg.login()
from time import sleep

counter = 0
tel_num = []
for x, value in df.Number.iteritems():

response = tg.call_method('importContacts', {
'contacts': [
{'phone_number': '+'+value},
]
})
response.wait()
counter += 1
user_ids = response.update['user_ids']
if user_ids[0] == 0:
print('This contact is NOT using Telegram.'+value)
sleep(15)
else:
print(f'¡This contact({user_ids[0]}) uses Telegram!'+value)
tel_num.append('+'+value)
sleep(15)