I built a similar thing a few years ago named ShellShare [1]. It's much simpler than what you're building. Free software and read-only (think broadcast).
I wish you all the best in your startup.
Yep, we didn't invent the wheel but we made it easier to use it. Just two clicks to get a link :-)
This isn’t a problem with tmate, however. I’ve been using tmate for several years, and it works great. How does Termius differ?
Also, you said that both sides need Termius for sharing to work. With tmate, only one person needs it. The other person can SSH in, or they can even just view it in their web browser.
Btw, is there any feature that you always wanted in tmate? I'm asking because we are going to develop the Terminal Sharing.