Two observations: 1. If you look at the contract, there will almost definitely be a clause where the company will claim rights over all IP that you generate,

Two observations: 1. If you look at the contract, there will almost definitely be a clause where the company will claim rights over all IP that you generate, and that you need to pre-declare any IP that you already own (otherwise they will have the right to claim it). If there isn't, there should be and it's OK to push back against it not being there. Once that is sorted, write up a declaration of all the ideas that you have had so far for your side hustle and submit it to the company. (You don't have to go into detail: bullet points are fine.) This gives both you and the employer the protection they are looking for. 2. Starting a business is mostly not about the IP of the software. I have had customers go bananas over something that I spent a day writing. (I have also had stuff that I spent a year writing go nowhere and never sell.) Most of the ideas that you think are good will be impossible to sell profitably. The first step in any business is establishing that there's a real customer need, and that you can reach those customers. You will probably try 20 different ideas before one works. Buy adwords for them, or do some other kind of outreach to customers and see what works: you also need to go and talk to potential customers. (e.g. every Saturday meet up with someone). Off the back of this you will eventually find something that works, that's easy to sell and easy to explain, and you will probably have a backlog of customers wanting to buy it. You will also discover that it's probably only a few weeks' work to build the prototype. You can then approach your employer and discuss what you want to do, and get an exemption to the IP clause, or quit and use your savings. If your first thought on starting a business is to start coding, you're setting yourself up for failure.