Clerk - Clerk.io, the artificial intelligence for e-commerce that knows your customers interests.
Avochato - Text messaging for your business.
Twilio for Slack - Enable SMS conversations with Slack+Twilio
Message Me - Website to create your contact business card
Spike.sh - Spike is an incident management platform that alerts via slack, phone and email and automatic escalations to help teams fix infrastructure problems.
StackWhats - Add the WhatsApp Live Chat to your website