If there are two or more developers wanting to apply, the first with a minimum viable product wins.
That is working on spec and is damaging to the development industry. This is not how business is done in a professional environment. While I can understand wanting something to put your hands on before spending money, you don't tell 2 contractors to go build a house for you and decide to pay for and hire the one that finishes first.
I'm pretty annoyed that you even thought that this type of practice would be acceptable and hope no quality developers are bored enough to entertain this. Surely no professional devs will unless they are just bored.
This is an insult to the development industry.
You not only have a shaky product with all sorts of risks and dangers for the users, but the way you wish it to be developed is insulting to the developers themselves. I'd be surprised if you get anywhere this way with any sort of actual quality.
I was actually excited when i saw this post.
Then i read it. Excitement vanished instantly, replaced by a bit of disgust.