Developing a website isn't "doing business" - plenty of people have personal websites, club websites, academic websites, project websites, etc. You can certainly talk to people, put an idea up for feedback, write code, etc. without incorporating or getting a business license.

You do generally want to incorporate before any money changes hands, though. You'll need to to get a business bank account, and if you don't have a business bank account and are doing everything out of a personal account, you're personally liable if anyone isn't satisfied with their transaction.