Backlink is a link from any external domain pointing to your site; it is also called external or inbound links. The concept of backlink is very simple that more useful content is expected to be referenced by many other site owners. Since this makes sense, Google and other search engines provide more weightage in the algorithm to list pages with more backlinks on top of the search results pages.

The backlink checker tool is very simple to use. Just enter any URL and hit submit button to see the number of backlinks pointing to that domain. This tool uses Alexa backlink API to show the count hence it is reliable.