These terms are used interchangeably more than often. While both play a significant role in rankings and user experience, they aren't entirely the same. The main difference between the two is the layout of the information. With mobile-friendly sites, the designed code shrinks to an exact copy of the website visible on a computer to fit it into the small screen of a mobile device.On the other hand, responsive websites restructure their entire content, so it's displayed across all devices in an aesthetically pleasing, easy-to-read format. Responsive sites create a positive user experience while allowing users to navigate the full site with ease. In simple words, all responsive websites are mobile-friendly, but not all mobile-friendly websites are responsive.