Security - Access key
If you'd like to protect a website that you've made you can use the access key panel.
The access key is great when developing websites because it means you can set an access key, once you've visited the site once using that key you'll be able to see and manipulate the site, but anyone who hasn't won't be able to.
It means you can develop while your URL is live or you can develop and give the key to a select few testers or clients without everyone else being able to see.
If you visit the site you can enter the access key or you can give the link to someone and they will click it and they will never even know they needed a key.