I just started developing a StackOverflow client, and wanted to add authentication. I found out I needed to register for that and wasn't sure if it was okay to register your app when it is not yet published. From this answer:
When they say that no-key is for testing, they mean people that are just playing around with the API and have no interest making an application yet. If you at all have any plans for an application, by all means make an API key. Even if you don't know all the info for the app, still register it and go back and change it later.
I gather it is okay to do so when you're still testing.
My app is nowhere near publishing yet, so it doesn't have a website (Even if - not when, I'm a hobbyist - I publish my app, I'm not sure if it will have a website). So I thought I'd just leave that field empty. But it complains 'Website URL is required'. Another answer here on StackApps said there were plenty of Stack applications without website and that it was perfectly normal to don't have a website for your app. So what should I enter in the Website URL field?