WhatsApp Web - A WhatsApp client for web
GetChat.App - Add WhatsApp chat to your website for free
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Smooch.io for Facebook Messenger - Message your customers from Slack, Front, a bot or anywhere!
Number To Whatsapp - A utility tool which lets your start a Whatsapp conversation without saving the contact of the said person first.
Avochato - Text messaging for your business.