What's the best way to find non-paying customers?

Hey everyone,

It's been 4 months since my last update and I'm now 16 months into my SaaS startup journey.

I've been working on a markdown website builder called Luna:
https://onluna.io

I'm trying to find people that want to use app & give feedback so I created a demo hoping to attract such individuals:
https://www.youtube.com/watch?v=v8l6rbVE76E

The demo illustrates how you can publish a website in under 60 seconds, including the time it takes to login. I'm planning on sharing it in a few subreddits I follow.

I'd love some ideas on how to find more non-paying customers in order to work out the wrinkles in the app.

Thoughts/feedback/advice would be much appreciated!