Backlink Gap

Summary#

Backlink Gap compares your referring domains against those of up to five competitors and lists the domains that link to at least one competitor and not to you. Every row is a real domain from the provider's backlink index with its authority, backlink count, referring pages, spam score and first-seen date, and it names which of your competitors it links to.

Purpose#

The question a link builder actually asks is not "who links to my competitor" but "who links to my competitor and has never heard of me". Those are different lists, and the difference is every site that already links to both of you. Those sites look like the best opportunities on any competitor-backlink list because they are relevant and high authority, and they are the one set that is not an opportunity at all: you already have the link.

This tool does the subtraction, so the list you work from contains only domains you do not have.

Overview#

Enter your domain and one to five competitors. Metric Vault fetches the referring domains of every named site, builds the set of domains already linking to you, and subtracts it from the union of the competitors' referring domains. What is left is the gap.

The rows are ordered by how many of your competitors each domain links to, with authority breaking ties. That ordering is the point of the report. A site linking to one competitor might be a coincidence of their niche. A site linking to four of them publishes about this category, links out routinely, and does not know you exist.

Nothing in this report is generated. It does not go through the AI path at all, because every field is a provider measurement or a set operation over provider measurements, and a model given a list of real referring domains will add a few that do not exist.

Benefits#

• The list contains only domains you do not already have, so no outreach is wasted on a link you own.
• Ranked by shared coverage, so the sites most likely to cover your category are at the top rather than merely the biggest ones.
• Every row names the competitors it links to, which is the opening line of the pitch.
• Exports to CSV with every row of the report, in the same order.

Use Cases#

• Building a first outreach list for a site with few backlinks.
• Finding the publications, directories and resource pages that cover every player in a category except you.
• Auditing why a competitor outranks you on links rather than on content.
• Handing a client a defensible list of named targets with the reason attached.

Requirements#

• A paid plan.
• Your own domain, and at least one competitor domain.

Permissions#

Available to any signed-in user on a paid plan. No admin role is required.

Cost#

2 credits per run. The tool makes one provider call per named site, so a comparison against five competitors is six calls. It is priced with the other multi-call comparison tools rather than the single-endpoint ones.

Navigation Path#

Sidebar → Backlink Gap (in the same group as Link Prospector).

Inputs#

Up to five competitors are compared. More than five are ignored rather than charged for. A competitor spelled the same as your own domain — including a www. prefix, a scheme, a path or a different case — is rejected before the run, so you are not billed for comparing a site with itself.

Step-by-Step Guide#

1. Open Backlink Gap from the sidebar.
2. Confirm your domain, or type it if no website is connected.
3. Name one to five competitors.
4. Select Find Gaps.
5. Read the top of the list first — those are the domains linking to the most competitors.
6. Select Export CSV to take the whole list into your outreach tool.

Reading the Results#

Gap domains is the number of rows found: domains linking to a competitor and not to you.

Link to every competitor counts the domains that link to all of the competitors you named. On a comparison of four or five sites this is the shortest and most valuable list in the report.

Your referring domains is the provider's total for your own site, shown so the size of the gap can be read against the size of what you already have.

The coverage line below the counters says whether the comparison was complete. Up to 700 referring domains are read per site. When every named site had fewer than that, the line reads Complete comparison and the gap is the whole gap. When any site had more, the line reads At least N gap domains — the number is a floor, not a total, and the real gap is larger than the list.

Which competitors names the sites each domain links to, so the outreach angle is visible without opening anything.

Spam score and First seen come from the provider untouched. A high spam score is a reason to skip a row, not a reason for the tool to hide it.

If a competitor's backlink data cannot be fetched, the report says so by name and excludes that competitor entirely rather than reporting a smaller gap as if it were the whole one.

Examples#

Comparing a small SaaS site against three established competitors typically returns a few hundred gap domains, of which a handful link to all three. Those few are the list to start with: they are demonstrably willing to cover every product in the category.

Screenshots#

Not documented. The result is a single sortable table under the run row.

Tips#

• Name competitors that are close to your size. A comparison against a site fifty times larger returns a gap you cannot act on.
• Start with the rows that link to every competitor, not with the highest authority. Relevance converts; authority only matters once they say yes.
• Re-run after a link-building push to measure what closed.

Best Practices#

• Use three to five competitors. One competitor produces a list you cannot rank by shared coverage, which is the report's main signal.
• Check the coverage line before quoting a gap size to anyone.
• Cross-check a promising row in Backlink Profile before pitching it.

Common Mistakes#

• Reading the row count as the total gap. When the coverage line says At least, the count is a floor. See Reading the Results.
• Comparing against a site in a different market. The gap will be large and irrelevant.
• Treating every row as reachable. A referring domain can be a scraper, an expired domain or a spam network. The spam score column is there for that.

Limitations#

• Up to 700 referring domains are read per site. Sites with more than that produce a floor rather than an exact gap.
• Up to five competitors per run.
• The report describes referring domains, not individual linking pages.
• Coverage is whatever the provider's backlink index holds. A very new link may not appear yet.

Troubleshooting#

"Enter your domain and one to five competitors" The query had no competitor in it. Fill at least one competitor field.

"Pick a competitor other than your own website" One of the competitor fields names your own site. The check ignores www., the scheme, any path and letter case.

No gap found Every domain linking to those competitors already links to you. This is a real answer, and on a mature site it is a good one. Compare against different competitors to find a new pocket.

A competitor is named as having no data The provider returned nothing for that domain. Check the spelling, then re-run. Nothing from that competitor is included in the report.

FAQs#

Is this the same as Link Prospector? No. Link Prospector picks competitors for you and writes an outreach pitch for each prospect. Backlink Gap compares the competitors you name and returns the measured set difference with no generated text at all.

Why does a domain with a huge authority score sit below a smaller one? Because the smaller one links to more of your competitors. Shared coverage ranks above authority, and authority only breaks ties.

Does the export match the report? Yes. The CSV contains every row of the report in the same order, with the same columns.

Can I run it on the Free plan? No. It requires a paid plan.