A classic Lean Startup-inspired technique for validating startup ideas is to put up a landing page to gauge interest.
At a minimum you should collect email addresses, but even better is to get customers to pay you a deposit to prove they value your product, perhaps even before you have a product.
Here's a quick tutorial on how to do that, absolutely for free, with a static HTML template, Netlify, and https://trolley.link - in about 10 minutes.