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

Slaask - Slaask enables you to set up a dedicated live chat channel on your Slack.

ChatWoot - Open-source omnichannel customer engagement platform

JivoChat - JivoChat is a live chat that enables you to talk to visitors on your website

Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Chatlio - When you have a business to run, your average instant messaging software just will not do. You need an internal presence upon which your entire team can collaborate on. Read more about Chatlio.