WhatsApp Contact Bot

Simple Telegram bot that allows you to start a WhatsApp chat with people not in your contacts. Responds with a link that can be opened in WhatsApp.

You can find a deployed bot here http://t.me/WhatsAppContactBot

Why?

WhatsApp allows you to start chats with someone not in your contacts by using https://wa.me/<PHONE NUMBER>. The problem is that I can never recall this URL whenever I need this functionality. Although I don't often encounter it, when I do, I typically need it quickly.

To over-engineer this, here's a simple Telegram bot that returns a shortlink given a phone number.

I also took this opportunity to learn more about Netlify functions and get up to speed about the changes with Telegraf.

Setup

Telegram BotFather

You'll need to create a bot by talking to BotFather.

1. Start a chat with the BotFather
2. Create a new bot via /newbot
3. Specify the name of the bot and username of the bot
4. Note down the access token, which will be used below

Netlify

Netlify deploys the function that Telegram will call whenever a message is sent to the bot.

1. Fork the repo
2. Go to https://github.com/apps/netlify/installations/new to ensure that Netlify has access to the repo
3. Import the repo into Netlify and follow the steps to deploy
4. Go to Settings > Build & deploy > Environment
5. Add a TELEGRAM_BOT_TOKEN variable and enter the access token you found from before
6. Trigger a redeploy

Telegram webhook

To get the bot to work, you need to let Telegram know about the location of the deployed function.

1. In Netlify, go to Functions and select the main function. Look for the Endpoint.
2. Open .env and set the NETLIFY_URL to the endpoint found in step 1.
3. Run npm run webhook-setup

Telegram bot usage

Once the above has been set up, you can start using the bot!

1. Enter /start to see the welcome message
2. Enter any number to get a shortlink
3. Click on the link to open up the WhatsApp chat

Development

Currently, you can only run tests and perform a typecheck:

npm run test
npm run typecheck

I deployed directly to Netlify and performed manual tests on the bot as I didn't want to spend much time on this (it's a weekend project after all!).

There's room to explore Netlify Dev to run it locally before deployment. Having a test bot will be useful as well.