Telegram Inline keyboard without Command node

You will need read through the documentation of the telegram bot api.

This is the general idea, put this in a function node:

out = {
    method: "sendMessage",
    payload: {
        text: "Open the door",
        reply_markup: {
            inline_keyboard: [
                [{
                    text: "Yes"
                }],
                [{
                    text: "No"
                }]
            ]
        }
    }
}
return out;

command node -> function node -> telegram payload node
Set the telegram payload node method to -set-by-msg.method -

The command node is the trigger.