Backlink Gap Tool: Find the Referring Domains Linking to Competitors, Not You
Compare your backlink profile against up to 3 competitors and see exactly which referring domains link to them but not you — plus what content earned those links and how many you need each month to close the gap.
No credit card required. First gap comparison free on any plan.
| Domain | DR | Spam | Links to Comp. | Category |
|---|---|---|---|---|
| industryblog.com | 54 | 2% | 3 of 3 | Industry News |
| toolsdirectory.net | 38 | 6% | 2 of 3 | Directory |
| expertroundup.io | 47 | 1% | 2 of 3 | Blog |
What is a backlink gap tool?
A backlink gap tool compares your backlink profile against up to 3 competitor domains and identifies referring domains that link to them but not to you. SignalSumo shows the Domain Rating, spam score, link attributes, and category for each gap domain, audits which competitor pages earned those links in the first place, and recommends a monthly link velocity target to help you close the distance.
Key Takeaways
- A backlink gap analysis compares your referring domain profile against up to 3 competitor domains at once.
- Each gap domain is shown with its Domain Rating, spam score, link type (dofollow/nofollow), and niche category.
- The tool audits which specific competitor pages earned the most backlinks so you can reverse-engineer their strategy.
- A monthly velocity target tells you how many new referring domains to acquire per month to close the gap.
- Filtering by Domain Rating lets you prioritise high-authority prospects and skip low-value link farms.
- Revisiting the same competitor group does not consume extra report credits — only a fresh comparison does.
The easiest links to earn are the ones already linking to your competitors
Stop guessing where to focus your link outreach effort. Uncover competitor referral sources systematically.
Easy-win opportunities stay invisible
A site already linking to two of your competitors is a far easier outreach target than a cold pitch — but without a gap analysis, you'd never know it exists.
Outreach effort goes in random directions
Without a prioritized list, link building turns into guessing which sites might say yes.
There's no benchmark for "enough"
Without a velocity target, it's hard to know whether 5 new links a month is keeping pace or falling behind.
What earns links stays a mystery
Competitors' best-linked pages are a direct signal of what content attracts links in your space — and that signal is easy to miss.
A complete map of who's linking to them — and not to you
Unlock full insights into rival backlink strategies and target domains.
Referring Domain Gap Grid
See every referring domain that links to your competitors but not to you, ranked and ready for outreach.
Domain Quality Signals
Every gap domain comes with Domain Rating, spam score, link attributes, and category, so you can prioritize quality opportunities over volume.
Top Earning Content Audit
A tabbed breakdown of each competitor's top backlink-attracting pages, so you know exactly what kind of content is earning links in your space.
Link Velocity Targets
Get a recommended monthly target — for example, 5, 10, or 25 new referring domains — sized to the actual gap between you and your competitors.
Intersection Venn Visualization
See an interactive overlap chart of shared referring domains across your domain and your competitors, making the gap visually obvious.
Multi-Competitor Comparison
Run the gap analysis against up to 3 competitor domains at once, instead of comparing one at a time.
Smart Credit Usage
Re-viewing a cached gap analysis for the same competitor group is free. A fresh comparison on a new competitor group uses standard report credits, since it pulls new referring domain data.
From your domain to a prioritized outreach list in four steps
Get a detailed map of prospective link targets in minutes.
Add your domain
Select the primary project domain you want to find link gaps for.
Add your competitors
Enter up to 3 competitor domains to compare against.
We find the gap
SignalSumo identifies referring domains linking to them but not you, with quality signals for each.
Get velocity targets & outreach list
See your prioritized gap domains alongside a recommended monthly link-building pace.
See exactly what a real backlink gap analysis looks like
Review illustrative outputs comparing SEO metrics and finding high-value backlink opportunities.
Intersection Venn Visualization
See shared and unique referring domains. Identify links where multiple competitors rank to prioritize high-converting resources.
Link Velocity Recommendation
Recommended target: +10 referring domains per month to close this gap within 12 months.
Referring Domain Gap Grid
| Domain | DR | Spam Score | Links to Competitors | Category |
|---|---|---|---|---|
| industryblog.com | 54 | 2% | 3 of 3 | Industry News |
| toolsdirectory.net | 38 | 6% | 2 of 3 | Directory |
| expertroundup.io | 47 | 1% | 2 of 3 | Blog |
Top Earning Content Audit
| Page URL | Referring Domains |
|---|---|
| /blog/ultimate-guide | 84 referring domains |
| /free-template-pack | 52 referring domains |
Example output for a sample comparison. Your results will reflect your own domain and competitors.
Why find gaps with SignalSumo instead of a spreadsheet — or a generic free tool
Stop cross-referencing complex data exports. Build links using a simple, unified checklist.
| Feature | SignalSumo | Manual Backlink Spreadsheets | Generic Free Tools |
|---|---|---|---|
| Gap detection | Automatic, ranked by quality | Requires manually cross-referencing exports | Often limited to one competitor at a time |
| Content-source insight | Top Earning Content audit included | Not available | Rarely included |
| Velocity recommendations | Sized to your actual gap | Not available | Not available |
| Credit transparency | Cached views free, fresh lookups cost credits | N/A | Often unclear or capped abruptly |
Start Free — 7 Days of Full Pro Access
Mid
Built for Small Business Owners, freelancers who host or manage small businesses.
-
Unlimited Report Views & Export For All ToolsAI SEO, Backlinks, Competitor Intel, Keywords, Local SEO, Audits
-
Technical SEO Audits
-
Tracked Keywords
-
Keyword Research
-
Competitor Analysis
-
Backlink Intelligence
-
Backlink Monitoring
-
Content Optimizer
-
Google Search Console
-
Website Uptime Monitoring
-
AI Growth Plans
-
Team Members
-
White-Label PDF Reports
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Executive Reports
-
JavaScript Rendering
-
API Access
-
Prompt tracking
-
AI brand health by domain
-
AI visibility reports
-
AI content generation
-
AI-ready Site Audit
Pro
Designed for freelancers, consultants, marketers, and growing businesses
-
Unlimited Report Views & Export For All ToolsAI SEO, Backlinks, Competitor Intel, Keywords, Local SEO, Audits
-
Technical SEO Audits
-
Tracked Keywords
-
Keyword Research
-
Competitor Analysis
-
Backlink Intelligence
-
Backlink Monitoring
-
Content Optimizer
-
Google Search Console
-
Website Uptime Monitoring
-
AI Growth Plans
-
Team Members
-
White-Label PDF Reports
-
Executive Reports
-
JavaScript Rendering
-
API Access
-
Prompt tracking
-
AI brand health by domain
-
AI visibility reports
-
AI content generation
-
AI-ready Site Audit
Agency
Designed for agencies managing multiple client campaigns with White-label reports & workflows..
-
Unlimited Report Views & Export For All ToolsAI SEO, Backlinks, Competitor Intel, Keywords, Local SEO, Audits
-
Technical SEO Audits
-
Tracked Keywords
-
Keyword Research
-
Competitor Analysis
-
Backlink Intelligence
-
Backlink Monitoring
-
Content Optimizer
-
Google Search Console
-
Website Uptime Monitoring
-
AI Growth Plans
-
Team Members
-
White-Label PDF Reports
-
Executive Reports
-
JavaScript Rendering
-
API Access
-
Prompt tracking
-
AI brand health by domain
-
AI visibility reports
-
AI content generation
-
AI-ready Site Audit
Free.
$0 /moPerfect for testing SignalSumo and monitoring a small website.
Detailed Plan Comparison
| Feature / Quota Limit | Starter | Mid | Pro (Best Value) | Agency |
|---|---|---|---|---|
| Money Tools & Intelligence Reports | ||||
|
Unlimited Report Views & Export
AI SEO, Backlinks, Competitor Intel, Keywords, Local SEO, Audits
|
Unlimited | Unlimited | Unlimited | |
| Money Tools Suite Coverage | Limited Preview | Full Suite (AIO, Backlinks, Competitor, Keywords, Local SEO, Audits) | Full Suite (AIO, Backlinks, Competitor, Keywords, Local SEO, Audits) | Full Suite (AIO, Backlinks, Competitor, Keywords, Local SEO, Audits) |
| Account & Workspace | ||||
| Tracked Projects / Domains | 1 | 5 | 10 | 25 |
| Uptime Monitors | None | 5 | 10 | 25 |
| Uptime Check Frequency | Every Minute | Every Minute | Every Minute | Every Minute |
| Instant Downtime Email Alerts | ||||
| Team Members / Users | Just You | Just You | Up to 2 Users | Up to 5 Users |
| Free SEO Tool Checks / mo (all flagship tools, shared) | 10 | 25 | 30 | 100 |
| Technical SEO | ||||
| SEO Audit Reports / mo | 1 | 20 | 10 | 30 |
| Max Crawled Pages per Audit | 200 pgs | 5,000 pgs | Unlimited | Unlimited |
| SEO Score Analysis | ||||
| Page-Level SEO Analysis | ||||
| Core Web Vitals Analysis (pages per audit) | 1 pgs | 3 pgs | 5 pgs | 10 pgs |
| JavaScript Crawling Support | ||||
| Audit Progress History Window | 1 Month | 6 Months | 1 Year | 2 Years |
| Weekly SEO Monitoring Cadence | Monthly | Bi-weekly | Weekly | Every 3 days |
| Monitored Pages per Website | 3 | 6 | 10 | 15 |
| Rank Tracking | ||||
| Tracked Keywords Limit | 3 | 100 | 750 | 2,000 |
| Visibility Tracking | ||||
| Ranking History | ||||
| New Keywords Added / mo | 6 | 120 | 900 | 2,400 |
| First Rank Check for New Keywords | 7 Days | 3 Days | 3 Days | Within 24 Hours |
| Rank Re-Check Frequency | Weekly | Weekly | Weekly | Every 5 days |
| SERP Tracking Depth | Top 20 | Top 30 | Top 50 | Top 50 |
| Keyword Discovery (results per run) | 20 Keyword Suggestions | 50 Keyword Suggestions | 75 Ranked Keywords | 100 Ranked Keywords |
| Keyword Research | ||||
| Keyword Searches per Month | 10 | 25 | 75 | 200 |
| Volume & Difficulty Analysis | ||||
| Competitor Analysis | ||||
| Competitor Analysis Reports / mo | 1 | 10 | 30 | 75 |
| Competitors per Analysis | 2 | 3 | 3 | 5 |
| Keyword Gap Analyses / mo | 2 | 20 | 30 | 100 |
| Smart Competitor Suggestions (auto-detected, refreshed every 30 days) | ||||
| Backlink Intelligence | ||||
| Backlink Intelligence Reports / mo | 2 | 15 | 35 | 75 |
| Backlink Explorer Searches / mo | 3 | 25 | 35 | 100 |
| Backlink Rows per Report | First 50 | 200 / page | 200 / page | 200 / page |
| Backlink Growth History | ||||
| Backlink Monitoring (Domains) | None | 1 | 10 | 25 |
| backlink gap tool Reports / mo | 1 | 10 | 20 | 50 |
| Broken Links Reports / mo | None | 5 | 15 | 50 |
| Link Opportunities Reports / mo | None | 10 | 20 | 60 |
| Monitor Refresh Interval | 30 Days | 7 Days | 7 Days | 7 Days |
| AI Intelligence & Growth Engine | ||||
| AI Tracked Projects / Campaigns | None | 1 | 5 | 25 |
| Tracked AI Prompts | None | 15 | 75 | 100 |
| Monthly AI Visibility Checks | None | 20 | 100 | 250 |
| AI Check Frequency | — | Weekly | Weekly | Weekly |
| GEO Score™ & Perception Tracking | Sample | |||
| AI Growth Plans / mo | None | 5 | 10 | 35 |
| AI Executive Summaries / mo | None | 25 | 50 | 150 |
| AI Intelligence Center (ChatGPT & Gemini) | 1 Credit / query | 1 Credit / query | 1 Credit / query | 1 / mo |
| Content Optimizer Reports / mo | None | 10 | 30 | 100 |
| SEO Opportunity Recommendations | ||||
| Growth Roadmaps | ||||
| Pay-As-You-Go Credits | ||||
| Bonus Credits Included / mo | 1 | 2 | 5 | 25 |
| Credit Top-Up Packs (from $10) | ||||
| Reporting | ||||
| PDF Reports | ||||
| CSV Exports | ||||
| Scheduled Reports | No | Weekly | Weekly | Every 3 days |
| White Label Reports | ||||
| Audit Embed Widgets (lead capture on your site) | None | None | 1 | 25 |
| White-Label Embed Widgets | ||||
| Developer API | ||||
| REST API Access | ||||
| API Calls / month | 20 / mo | 100 / mo | ||
| API Key Management | ||||
| Support | ||||
| Support Ticket Priority | Community | Standard Email | Priority Email | Dedicated Slack |
| Dedicated Account Manager | ||||
Included in every paid plan
No feature gates, no add-on pricing — every plan ships with the essentials.
* White label and API access are available from the Agency plan up — see the full breakdown above.
Save Up To 70% Compared To Purchasing Separate SEO Tools
Most SEO workflows require multiple subscriptions for audits, rankings, backlinks, reporting, and competitor research. SignalSumo combines everything into one platform.
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Backlink monitoring →How to Use Backlink Gap Analysis in Your Link-Building Workflow
A backlink gap report is only as valuable as the outreach strategy it feeds. Here's a step-by-step workflow for turning gap data into actual referring domains.
Pick the Right Competitors
Compare yourself against sites that rank for the same keywords you're targeting — not the biggest brands in your industry. A DR 90 site will have referring domains you can't realistically earn. Choose competitors within 15–20 DR points of your site for an actionable gap list.
Filter by Domain Quality
Sort the gap list by Domain Rating and filter out anything with a spam score above 10%. Your outreach time is finite — prioritise DR 30+ domains linking to multiple competitors, as these sites clearly operate an editorial linking policy and are more likely to respond to genuine outreach.
Study the Top Earning Content
Before reaching out, understand why those referring domains linked to your competitors. Was it a data study? An ultimate guide? A free tool? The Top Earning Content audit shows you exactly which assets attracted the most links — giving you a content brief before you even write a word.
Set a Monthly Velocity Target
Use the link velocity recommendation to define a monthly target — not as an arbitrary goal, but as the minimum cadence needed to close the gap within a realistic timeframe. Tracking this number monthly keeps your link-building accountable against competitor momentum rather than an internal vanity metric.
What Makes a Referring Domain Worth Pursuing?
Not every domain in your gap list deserves outreach. Here's the scoring framework that separates high-value targets from noise:
| Signal | High Priority | Medium Priority | Skip |
|---|---|---|---|
| Domain Rating | DR 50+ | DR 25–49 | DR <25 |
| Spam Score | <3% | 3%–10% | >10% |
| Links to competitors | 3 of 3 competitors | 2 of 3 competitors | 1 of 3 only |
| Site category | Industry publication, editorial blog | General directory, roundup site | Link farm, PBN, unrelated niche |
| Link type earned | Editorial in-content dofollow | Resource page, footer | Comment, forum profile, nofollow-only |
A Realistic Link-Building Sprint (30 Days)
Frequently Asked Questions
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