[rurban]

It was your code. His idea, but your code. Code is the work, not the idea. You cannot let him get away with your code for nothing.

Ask a lawyer what you can charge him to buy your code. 400K might be a lot, but a good starting point for a deal.

[slamus]

Thanks for your answer but:

1 - He payed me for my work as an employee of is company

2 - Don't want to get lost into legal stuff, since I've got so many other things to care for (work + family + enjoying my life :) )

[computer]

If you got paid as an employee to build the app, his position isn't as weird as it seems (ignoring verbal promises). After all, he had already borne most of the risk at that point.