whatsapp-web.js

A WhatsApp API client that connects through the WhatsApp Web browser app

It uses Puppeteer to run a real instance of Whatsapp Web to avoid getting blocked.

NOTE: I can't guarantee you will not be blocked by using this method, although it has worked for me. WhatsApp does not allow bots or unofficial clients on their platform, so this shouldn't be considered totally safe.

This is still very much a work in progress, but you can check out example.js to see how to read and send messages.