Free backlink checker: see who links to any website.

Without an account you see every total and the first five referring domains; a free account lists up to 500 referring domains with their anchors and individual links. The checks are reads of MrKeyword's own data, not calls to a paid API, so the limits exist only to stop the index being copied wholesale.

From two places MrKeyword runs itself: its web graph, which records which domains link to which across about 135 million domains, and its own crawler, which records individual links on the pages it has fetched. No third-party backlink index is bought or resold, and each referring domain is labelled with the source that found it.

• MrKeyword's web graph is domain-level. It knows that one domain links to another, and how many domains link to each, but not which page, which anchor text or which link attributes. It is rebuilt with each new release, every few months, and new and lost domains are counted between releases. Rankings are kept for the top 50 million domains.
• MrKeyword's crawler is page-level. For each link it has fetched it keeps the linking page, the page linked to, the anchor text, whether the link is followed, nofollow, sponsored or UGC, and whether it is a text, image or empty link, with when it was first and last seen. It has visited far fewer pages than the web graph covers, so for big sites its link count is much smaller than the referring-domain count.
• For your own websites, a workspace can add the links Bing Webmaster Tools reports and import the link exports from Google Search Console, Ahrefs Webmaster Tools or Bing. Those are merged into your own report and never shown to anyone else.

A few rules keep the count honest. Links between pages of the same site are left out. Links from infrastructure domains such as CDNs and analytics services are filtered so they never appear as backlinks. Links to a subdomain count for the main domain, and www. is ignored. In the app, a linking domain that is one of your own websites, or shares your site's name, is flagged, because those links were probably not earned.

A useful backlink comes from a real website about something related to yours, sits in the body of a page a person wrote, and would send a reader to you even if search engines did not exist. A link from a local news story about your business, or a guide that cites your data, fits that description. A link in a sitewide footer of an unrelated site, or one of hundreds on a directory page, mostly does not.

Variety matters more than volume: links from many different domains build authority faster than many links from the same few. Anchor text should read naturally, which in practice means mostly your brand name and your address, with a few descriptive phrases. A profile where most anchors are the exact keyword you want to rank for looks manufactured, because it usually is.

Do not buy links that pass ranking credit, and do not join link schemes. Google's spam policies name both, and the risk is that every link you paid for is discounted at once. Earn links with things worth citing, and mark any paid placement as sponsored.

Enter the competitor's domain in the checker above: it works for any public website, and the result shows their referring domains, authority and strongest linking sites exactly as it would for yours. Then read it against your own numbers.

1. Check your own domain first. Enter your site above and note its referring domains and authority. A competitor's numbers only mean something next to yours, read in the same tool.
2. Check each competitor the same way. Enter the competitor's domain, without a page path: the checker counts links to the whole domain, its subdomains included. Run the sites that outrank you for your main keywords, not just the brands you know.
3. Read the gap, then the list. The difference in referring domains and authority tells you how far behind or ahead you are. The first five domains show who the strongest linking sites are; a free account lists up to 500, strongest first.
4. Find the sites worth contacting. A site that links to two or more of your competitors but not to you is the best lead: it already links to pages like yours. Inside the app, the Backlink gap tab in Competitor Analysis lists those domains for you.

Links tend to follow traffic and authority, so the website traffic checker and the bulk domain authority checker are the natural next look at the same competitors: up to five sites side by side, with no account.

Partly: the checker works at the domain level, and only the links MrKeyword's crawler has fetched carry the exact page they point to. The web graph records that a domain links to yours, not which of your pages, so a page-level answer is only as complete as the crawl.

In a free account, the backlinks table names the target page of each crawled link, so you can see which pages earn links. For your own website, the best free source is Google itself: the Links report in Search Console lists your top linked pages and the sites that link to each one. Our guide to finding backlinks in Google Search Console shows where the report is, what its sample leaves out and how to export it. Import that export into MrKeyword and those links join your own report, beside the crawl and the web graph.

Paid backlink tools run their own large crawlers and keep years of link history; free checkers either show a slice of a paid index or, like this one, show what their own smaller data has seen. Both are estimates of the same unknowable thing, because no tool crawls the whole web.

• Coverage. A large paid index usually finds more individual linking pages, especially on big sites. MrKeyword's web graph counts linking domains across much of the web, but its page-level crawl is far smaller.
• History. Paid tools typically chart links over months or years. Here, new and lost domains are counted between web graph releases, and a website you add to MrKeyword gets its authority and referring-domain history charted from then on.
• Depth per link. Paid tools usually show every link's page, anchor and attributes. Here that detail exists for links MrKeyword's crawler has fetched, and the rest are listed as domains.
• Your own data. For your own site, Google Search Console and Bing Webmaster Tools are free and show links the search engines themselves have found. Any checker, free or paid, is best used beside them, not instead of them.
• Transparency. Whatever you use, prefer a tool that says where each number came from. Compare sites inside one tool, and never set one tool's count against another's.

If you are weighing up paid options, our comparison of Moz alternatives covers what the main backlink tools offer, and what backlinks are and how Google uses them explains which numbers matter before you pay for more of them.