IANAL but I was in a similar situation (didn't end up going through with it) and did some research. The technical answer is you are probably in the clear unles

IANAL but I was in a similar situation (didn't end up going through with it) and did some research. The technical answer is you are probably in the clear unless some part of the app's flow or design was "non-obvious", and obviously you can't re-use code. The real answer is if your old company decides to sue you, you won't be able to pony up the money for lawyers to fight it. If you get huge before they figure out and sue you, then at best you have a crazy expensive settlement on your hands. Don't do it. ideas are dime a dozen, why not pick one that doesn't have strings?