tawk.to - tawk.to is a free live chat app that lets you monitor and chat with visitors on your website or from a free customizable page
Twilio - Brings voice and messaging to your web and mobile applications.
ChatWoot - Open-source omnichannel customer engagement platform
Plivo - Plivo simplifies your customer engagement.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.