JSBin

JSBin is an online HTML code editor which like JSFiddle, supports HTML, CSS, and JavaScript. But the few things that distinguish it from JSFiddle are its speed and features. JSBin allows you to even test your code on mobile.

Then there are features like code casting and custom starting code, which again make this online HTML editor, amazing to use.

Yes, you can see the output of your code in real-time as JSBin allows real-time preview. It's a great minimal HTML editor online for free. There are additionals features available but with the premium plan.