SimilarSites.com a site where you can Discover the best websites and alternatives on the web. It simply shows the alternative to sites.All you have to do is Simply type the site URL in their site search bar and they will show you the alternative to that site.
You can also download the SimilarSites.com Browser Extensions for your browser which is available as under follows:
They also have a Similar Sites API. By the Similar Sites API, your site or application could benefit from the wealth of data which powers Similarsites.com.