a backlink gap analysis finds the domains that link to your competitors but not to you in the selected dataset. crawlgraph offers a free five-domain preview after an email step; fuller results and exports require paid access. the result is a research shortlist: verify the linking pages, current links and editorial fit before contacting anyone. this guide compares the workflow and its limits; start with our free backlink research guide if you are still choosing a data source.
what is a backlink gap analysis?
a backlink gap analysis compares the referring domains of two or more competitors against your own and returns the domains that link to them but not to you. ahrefs calls its version link intersect; semrush calls it backlink gap. the underlying idea is identical: a site that links to several of your rivals and not to you is a candidate to investigate. check the actual linking page, audience and current context before treating it as an outreach prospect.
a domain recorded for several close competitors gives you a concrete place to investigate. overlap and authority can prioritize that research, but neither establishes relevance, a current link, or a likely reply.
how do you find sites that link to your competitors but not you?
the mechanic is a set subtraction. list every domain linking to each competitor, union those lists, then remove domains recorded for your own site. what remains is your gap. the part that turns a raw gap into a usable outreach sheet is ranking: sort by how many competitors each domain links to, then by authority, then strip the platform and cdn noise (think wordpress.com, amazonaws.com, youtube.com) that links to everyone and means nothing.
you can assemble this by hand from any backlink export, or have a tool compute the overlap for you. either way the output you want is a short list where the top rows link to all of your competitors and none of them link to you yet.
inspect the retained seo-tool overlap study for a downloadable example with explicit source-data limits. the referring-domain rows still need current page-level qualification.
the single most useful link-building artifact is a list of domains that link to your selected competitors but not to you in the same snapshot. use it to plan page-level research before outreach.
seen enough? run it on your site free.
5 backlinks free. $99 once for unlimited site queries.
can you do a backlink gap analysis for free?
yes. the data exists in the open. the common crawl webgraph maps which domains link to which across 121.1M domains and 3.90B edges. crawlgraph updates its queryable data when a verified graph is imported. that is enough to compute a snapshot gap without paying for a proprietary index. the free gap-analysis tool runs exactly this: enter your domain and up to three competitors and it returns your top gap domains, already ranked by overlap and authority and with the platform noise filtered out. the free preview asks for your email and shows five gaps.
the honest limit: free shows five candidates, which still need page-level qualification. paid access unlocks a fuller ranked result and exports. the lifetime option is $99 paid once; an eligible visitor may also see a monthly option while the pricing experiment is enabled. free api access allows 15 backlink calls and no gap analyses per utc month; paid api access allows 1,000 backlink calls and 50 gap analyses. check current api limits and available plans before automating.
free vs paid: what you actually give up
the paid suites are not a scam. they buy you a fresher, deeper index and a pile of adjacent features. but for the gap analysis itself, here is the honest trade.
| ahrefs / semrush | free gap analysis | |
|---|---|---|
| gap / link intersect feature | check current plan eligibility | five-domain preview after email |
| price to run a gap | plan-specific; verify vendor pricing | $0 for the preview |
| index freshness | vendor-specific; verify current index | selected common crawl snapshot |
| index coverage | vendor-specific; test target domains | bounded by the selected snapshot |
| ranked by competitor overlap | ✓ yes | ✓ yes |
| platform / cdn noise filtered | check vendor workflow | automatic filtering; still inspect results |
| full export + api | metered / credits | $99 once (lifetime) |
| methodology | proprietary | open (common crawl) |
the short version: if you need daily-fresh data on a huge index, pay for a suite. if you need the gap itself, to build a prospect list and run outreach, the free path provides a small preview. paid access expands results and export access, subject to the documented result and usage limits.
the free workflow, step by step
whether you do it by hand or with a tool, the steps are the same:
1. pick 2 to 3 real competitors, the ones who rank for the terms you want.
2. export available referring domains from a consistent snapshot and note caps.
3. remove domains recorded for your own site in that snapshot.
4. rank what is left by how many competitors each domain links to, then by authority, and drop the platform and cdn noise.
5. inspect the linking pages, current links and contribution policy before drafting a relevant pitch.
the only step that is tedious by hand is the overlap and noise filtering at step 4, which is exactly the part a tool should do for you. the rest is judgment and outreach, which no tool can replace.
common questions
is the free data good enough? it can provide a starting shortlist. test your target domains and check the named release and row caps. a historical snapshot can miss new links or retain removed ones; it is not equivalent to a vendor's current index.
how many competitors should i use? two or three. one competitor gives you a long, weakly-sorted list. three lets you rank by overlap, which is what gives you a clearer order for manual qualification.
what do i do with the list? research the actual pages first. when a current, relevant page accepts contributions, give its editor a specific reason your evidence would help readers. overlap alone does not predict reply rates or establish permission to contact someone.
ready to see your own gap? run it free on the gap-analysis tool and start with the domains that link to all of your competitors and none of them link to you yet.
writes the queries we run internally. ships one tactical post a week.
plus one when a new common crawl release lands. that is all.