Ask HN: Encrypted Chat, on-the-fly?

Consider this scenario: you're talking to someone on one of the common social media platforms, where your chat is unencrypted/logged, and would like to talk about something more private.

Is there a service somewhere where you could simply send them a link, to open up a new tab in their browser, and commence a encrypted chat session right away (without them having to do any clicking other than open the link)?

Even an unencrypted service like this would be useful imho.