In order to create a chatbot in Viber, you have to register at the partners site here, then click on “Create Bot account”. Fill in the form then grab the access token.

Like other platforms, Viber requires a callback URL (web hook) to send messages to and must be accessible from internet (not just your local network), in order to test in your local environment, you can use ngrok to create a bridge between a public address and your local instance of RedBot:

ngrok http localhost:1880

You should get something like

Ngrok

Grab the https address you, something like https://123123.ngrok.io, this is the base url that points back to your Node-RED instance.

The callback is

<https://youraddress.ngrok.io/redbot/viber>

A Viber bot needs at least the access token and a working web hook in order to work. Note that unless other platforms that requires a callback (like Slack or Facebook Messenger), the web hook is required in the RedBot configuration (in Node-RED) and not in the Viber backend. P.S. After a chatbot is created in the Viber platform, it will not be possible to send a message in any client until a valid web-hook is set in the configuration.