You should have a non-disclosure agreement and a non-compete agreement with the paperwork the developer signed before starting to work on the app.
You can't prevent him from violating them, but you can sue him if he does.
(Of course, if he's in some other country, it might cost you more to sue than what you'd collect, which is why it's best to use local developers. You can get cheap developers from some countries, but you get what you pay for. [And yes, $100/hour is a normal rate for a good developer in the US. $25 for the whole job says "give me your idea to steal - you'll get an app that sort of works, but I'll fill in all the missing pieces and sell it under my name".])
06-15-2019 06:19 PM