How do I market an app while I wait for development?

So I have a prototype built, now I'm just waiting on hiring a developer for the actual algorithm code. I understand that hiring a developer is very expensive and due to the nature of my app, vibe coding isn't enough. I was thinking of trying to market the app before I go through with it so I'm not spending thousands on a developer for nothing. There are similar apps in the market but I'm not sure that its enough validation for MINE in particular. Any idea how to go about this?