Referring Domains Checker
List the distinct websites that link to a domain or page, then judge the profile by who links rather than by how many times they do.
A referring domain is a website that links to you at least once. Ten thousand links from one partner site still count as a single referring domain, which is why practitioners lean on this number when they want to know how broad a site's endorsement actually is. Type a domain to see every site pointing anywhere on it, or a full URL to see only the sites pointing at that page.
When you submit, you are sent to app.search.co, where the lookup runs against DataForSEO's backlink index and the results are grouped by linking domain. Your opening lookup costs nothing and asks for no login; to keep running lookups after that, create a free search.co account.
This page focuses on the domain-level view: concentration, diversity, growth in new linking sites and how to classify a list of domains into something a link team can act on. If you want link-by-link detail such as anchors and individual source pages, the backlink checker is the better starting point.
What the referring domains report contains.
Results are one row per linking domain rather than one row per link. That grouping is the whole point: it collapses sitewide repetition so you can see the actual population of sites that chose to reference the target. Expect the report to cover roughly the following.
- Total referring domains: the count of unique sites in the index that link to the target, the headline figure most people compare against competitors.
- The domain list: each linking site named individually, which is what you will actually review, tag and hand to outreach.
- Links per domain: how many links each site sends, which separates one-off editorial mentions from sitewide placements.
- Follow status: whether a domain's links are followed or carry
nofollow,sponsoredorugc, so you know which part of the population passes ranking signals by default. - Index strength metric: a relative strength figure calculated by the data provider, useful for sorting but not the same thing as any search engine's internal view.
Like any third-party index, coverage is partial. The list is a strong sample for comparisons between sites measured with the same source, and a weaker guide to precise totals.
Concentration, diversity and what a healthy distribution looks like.
Sort the list by links per domain, descending. In most natural profiles a small group of domains sends a large number of links each (partners, a parent company, a site that put you in a template) and a long tail of domains sends one or two. That shape is normal. What deserves scrutiny is when the top handful of domains account for almost all followed links, because the site's ranking support then depends on a few relationships that can disappear in one redesign.
Next, look at what kinds of sites make up the tail. A tail full of industry publications, local organizations, suppliers, customers and bloggers in your niche reflects a business people genuinely talk about. A tail made mostly of generic directories, auto-generated stats pages and sites in unrelated languages is padding; it inflates the count without adding much else. Two sites with an identical number of referring domains can be in very different positions once you read the tail.
| Tag | Typical examples | Weight in your assessment |
|---|---|---|
| Editorial | Trade press, niche blogs, news sites citing you in an article | Highest; the reason most sites rank |
| Relationship | Partners, suppliers, clients, associations, sponsors | Real but capped; often sitewide or sponsored |
| Platform | Social profiles, forums, Q&A sites, review platforms | Mostly nofollow or ugc; useful for discovery |
| Directory | Business listings, niche directories, citation sites | Low; helps local consistency more than rankings |
| Noise | Scrapers, stat pages, link farms, unrelated foreign sites | Ignore unless part of a pattern worth reviewing |
Tracking new and lost referring domains over time.
The count on its own is a snapshot. The more useful habit is to run the same target at a regular interval and compare. New domains that appear after a campaign, a product launch or a piece of research show you what actually earned links. Domains that vanish tell you about relationships that ended, pages that were removed on the linking site, or URLs of yours that broke.
Lost domains are often worth more attention than new ones. If a strong editorial site stopped linking, open its old article: perhaps the page was updated and your mention was swapped for a competitor, or your target URL now redirects in a chain or returns an error. Those are fixable, and fixing them recovers support you had already earned without new outreach.
Example: two sites with the same headline number.
The numbers below are hypothetical and exist only to show the reasoning. Suppose two regional accounting firms each show 400 referring domains.
- Firm A: about 60 domains are local business associations, chambers, university career pages and regional news. Roughly 200 are directories and citation sites. The rest are a mix of software vendor partner pages and small blogs.
- Firm B: around 300 domains are directories, profile pages and stats sites. About 40 belong to one network of loosely related finance blogs sharing a template. Only a couple of dozen are editorial.
On paper they are equal. In practice Firm A has a defensible base of relevant, hard-to-copy sites, while Firm B's count is mostly replaceable and partly concentrated in one network. If Firm B is your client, the plan is not "get more domains" but "replace low-value domains with editorial ones", and the backlink gap tool will show which editorial sites already link to Firm A.
Using the list to set link targets and scope work.
Once the list is tagged, the editorial and relationship counts become your working metric instead of the raw total. Compare those subsets against the top-ranking competitors for your priority keywords. If your editorial count is close to theirs, links are probably not the constraint, and the effort should go into content, internal linking or technical work. If you trail by a wide margin, you have a quantified gap to plan around.
Where a cluster in the noise tag looks deliberately manipulative rather than incidental, move it to a risk review in the toxic link checker instead of acting on it here.
Mistakes people make with referring domain counts.
The number is simple, which is exactly why it gets misused.
- Treating the total as a quality score: a count says nothing about relevance; 50 editorial domains can outweigh 500 directories.
- Counting networks as diversity: twenty sites run by one owner are one relationship, however many rows they occupy.
- Comparing a domain to a page: a competitor's whole-domain count against your single URL is not a fair comparison; check like for like.
- Reacting to a single dip: short-term drops often reflect index refresh timing. Confirm across several checks.
- Ignoring nofollow domains: a site that mentions you with
nofollowis still a site that knows you exist, and often a warm outreach prospect for a followed mention later.
A monthly referring domains check.
Run the target
Enter your domain, or the specific page you care about, and record the referring domain total with the date.
Tag the list
Label each domain editorial, relationship, platform, directory or noise, starting with the newest entries.
Compare with last month
Note new and lost domains, and open the pages of any lost editorial site to find out why.
Benchmark the subsets
Run two ranking competitors and compare editorial and relationship counts, not totals.
Referring domains questions.
What is the difference between backlinks and referring domains?
Are subdomains counted as separate referring domains?
How many referring domains do I need to rank?
Why did my referring domain count drop?
Is the data the same as Google Search Console?
Pair it with these checks.
Want more editorial domains, not more directories?
SEO.co's link building team earns placements on relevant, independently run sites, and every new referring domain is reported so you can verify it in this checker.