Customer development: problem interviews (do users have this problem?), solution interviews (does your solution work?), and validation interviews (will they pay?).
The method: find 10 people who would be users and talk to them. Listen more than pitch. Early: what frustrates them? What do they currently do? What would make this easier?
Build a test: landing page with signup, prototype, waitlist. Measure interest: signups, waitlist conversion, intent to pay. Don't assume—talk to users.