Here is the playground, an example community: https://introwise.com/communities/introwise
You'll have to sign up, but you can always leave/remove your account hassle-free. It's a very early announcement here, so even our homepage and marketing pages are still in development.
I'm particularly interested in what HN members think about our product. Many communities we are targeting - co-workings, incubators, coding schools, are very tech-heavy and mostly rely on Slack. But at the same time we've heard a lot from them about problems of running their communities on Slack - can become noisy, intimidating for newcomers, complicated for non-tech-folks, expensive. What tools are your communities using?
I'm a co-founder and the only developer, so ask me anything! The web app is SPA React backed by Firebase, event-driven server-less architecture.