GetChat.App - Add WhatsApp chat to your website for free
Glific - Uplift millions of lives with digital two-way communication
Smooch.io for Facebook Messenger - Message your customers from Slack, Front, a bot or anywhere!
Avochato - Text messaging for your business.
WhatsApp Chatbots by SendPulse - No-code chatbots and shared inbox for WhatsApp
Talkus - Chat with your website users from Slack