We added somany backlinks to my site. if there is some backlinks removed or gone how can i find that links ?
There is ahrefs, majestic, and moz as the ones that are checking backlinks constantly.
The easy way to use Google webmaster tool to find all 404 pages and fix them. To find the list of all 404 pages, you can login to Google webmaster account and under diagnostics click on Crawl errors. Click on not found and you will see a list of all the links which are giving 404 error.