How do I secure my startup idea while also getting investor and consumer attention?

I recently built the first demo of a startup idea I've been working on. It's nothing crazy yet—just a prototype that finally works.

I showed it to a few friends and colleagues to get some honest feedback. Thankfully, they liked the idea. The only thing everyone agreed on was that the execution matters way more than the idea itself.

But now I've got a question that's been stuck in my head.

How do you get people excited about your startup without someone just... copying it?

It feels like we're in a time where anyone can build almost anything with AI tools. If someone with a bigger team sees my demo, what's stopping them from making their own version before I even launch?

At the same time, I know I can't just keep everything private forever. If nobody sees the product, how do I get users? How do I attract investors? How do I know I'm even building something people want?

I've read that most investors don't sign NDAs for early-stage ideas, which honestly surprised me. They seem to care more about traction and proof that people actually want what you're building than the idea itself.

So now I'm trying to figure out where the balance is.

Do you build in public? Do you only show selected people? Do you launch as soon as possible? Or do you stay quiet until everything is polished?

I'm still new to building startups, so I'd love to hear from founders who've already gone through this.

How did you protect your idea while still getting the attention it needed?