Yes, it would be unethical. Simply put yourself in the shoes of your employer - what would you think if you were in their place? You've used the detailed busine

Yes, it would be unethical. Simply put yourself in the shoes of your employer - what would you think if you were in their place? You've used the detailed business knowledge you gained through their business to develop a product that competes in the same space (it doesn't matter if it's not a direct competitor - it might be part of their future development plans). And now you're going to also use the contacts you made through your job with them to sell your new product!? Of course they'll think it unethical. I think the only way to do this ethically would be to leave your employment and either go full-time on your new product, or do some freelancing in your current industry to support yourself, or find employment in a different industry before you start approaching potential customers. I'd go for the second option, myself, if you can.