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
Novocall - Novocall converts web visitors into sales calls in seconds.
ChatWoot - Open-source omnichannel customer engagement platform
OptinMonster - OptinMonster helps to convert abandoning website visitors into subscribers and customers.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Cavako - Convert more site visitors into leads and sales