LSD
APIEndpoint 26 of 40Link Authority / Backlink Gap / Link Opportunity Detection

Backlink Gap API

Find the local directories and link sources your competitors have but you don't.

Link gap analysis used to mean exporting CSVs from Ahrefs and Semrush, diffing them in a spreadsheet, and manually vetting opportunities. Ahrefs (Link Intersect at $129/mo) locks this analysis behind a dashboard. Semrush (Backlink Gap at $139.95/mo) caps you at 4 competitors. Moz Link Intersect ($99/mo) charges per-seat. We built the endpoint: your domain plus up to 5 competitor domains in, a list of high-authority referring sites you're missing out. 10 credits per analysis. Your agent does the rest.

Start Free — 50 CreditsView Docs

POST /v1/backlinks/gap · 10 credits per analysis

POST /v1/backlinks/gap5 of 127
Domains linking competitors, not you
austinchamber.orgDA 68

"Austin's top-rated plumbers"

dofollow
yelp.comDA 92

"ABC Plumbing"

nofollow
homeadvisor.comDA 89

"Visit website"

nofollow
austinmonthly.comDA 54

"best plumbers in austin"

dofollow
bbb.orgDA 91

"ABC Plumbing - BBB"

nofollow
▌ Ask your agent

These prompts are the new link-building workflow.

Connect Local SEO Data as an MCP server once (60 seconds, below). Then your agent finds link opportunities. Replace bracketed domains with your own.

Local link opportunity detection

Run a backlink gap analysis for [mybusiness.com] vs [competitor1.com], [competitor2.com], and [competitor3.com]. Flag any referring domains with domain rank >50 where we're missing a link.

Chamber and directory gap

Pull backlink gap for [mybusiness.com] vs top 3 competitors. Filter results to show only local domains (chambers, directories, association sites) we're missing.

Link velocity opportunity tracking

Compare [our plumbing company] vs [top 2 competitors] for backlink gaps. Pair with Backlinks API to rank opportunities by domain authority and identify sites gaining new links.

Pre-pitch competitive audit

Run a gap analysis for a prospect's domain [prospectsite.com] vs their 2 strongest local competitors. Show me the top 10 referring domains they're missing. That's my outreach list.

▌ Real response

What you get back

Live response for a local plumbing company comparing against two competitors. Real API response, May 2026.

response · application/json~6-10s · 10 credits
{
  "status": "success",
  "credits_used": 10,
  "data": {
    "your_domain": "abcplumbing.com",
    "competitor_domains": ["competitor1.com", "competitor2.com"],
    "opportunities": [
      {
        "referring_domain": "austinchamber.org",
        "domain_rank": 68,
        "links_to_competitors": [
          {"domain": "competitor1.com", "backlinks": 142},
          {"domain": "competitor2.com", "backlinks": 89}
        ],
        "links_to_you": false
      },
      {
        "referring_domain": "austinmonthly.com",
        "domain_rank": 52,
        "links_to_competitors": [
          {"domain": "competitor1.com", "backlinks": 67}
        ],
        "links_to_you": false
      },
      {
        "referring_domain": "bbb.org/austin",
        "domain_rank": 75,
        "links_to_competitors": [
          {"domain": "competitor2.com", "backlinks": 201}
        ],
        "links_to_you": false
      }
    ],
    "total_opportunities": 34
  }
}
▌ Returns

The gap analysis metrics that identify link-building targets

Referring domain list

Domains you're missing that link to competitors

Complete list of unique domains that link to at least one of your competitors but not to you. These are your most qualified link-building targets because they already link to similar businesses in your space.

Domain rank for each opportunity

Authority score of each link source (0-100)

Authority metric for every referring domain, so you can prioritize your outreach. A domain-rank 70 chamber of commerce is worth more than a domain-rank 25 blog. Focus on high-authority opportunities first.

Competitor link breakdown

Which competitors have which links

For each gap domain, see which of your competitors they link to and how many backlinks they point to that domain. Reveals which competitors are already well-positioned and which links are most popular.

Multiple competitor support

Compare against up to 5 competitors at once

Analyze the collective gap across your entire competitive set. If 3 out of 5 competitors all have links from the same chamber, that's your #1 priority. Pair with Backlinks API to rank these gaps by total referring domain count.

▌ Built for

What link operators ship with this endpoint

Pre-pitch link opportunity lists for consultants

Before the sales call, run a gap analysis for the prospect's domain vs their 2-3 top competitors. Walk in with a concrete list of 'here are the 15 directories and local sites where you can get links.' Closes deals with a concrete action plan instead of hand-waving.

→ For consultants

Competitive link benchmarking for agencies

Monthly gap analysis for all client sites vs their local competitors. Your agent flags new gap opportunities (competitor acquired a link, you haven't) and surfaces them in a ranked list. Build once, run monthly on cron, surface priority targets automatically.

→ For agencies

Link-building campaign targeting

Run gap analysis, get your top 20 opportunities, then pair with [Backlinks API](/backlinks-api) to pull full link details for each. Now you know not just 'they link to your competitor' but 'how many links, from what anchor text, when did they acquire it.' Use that intelligence to craft hyper-targeted outreach.

→ Backlinks API

Multi-location business reporting

For MSBs with 10+ locations, batch gap analysis across all locations in one agent run. Each location gets compared against local competitors in that market. Agent surfaces the top opportunities for each location, builds a prioritized outreach spreadsheet. No dashboard login required.

→ For local operators
▌ vs. the alternatives

Why not use Ahrefs Link Intersect, Semrush Backlink Gap, or Moz Link Intersect?

Link gap analysis tools are locked behind SaaS subscriptions. Here's why the API model is fundamentally better for agents doing real link-building work.

ToolCost modelCompetitor limitSetupAI-agent ready
Ahrefs Link Intersect ($129/mo)$129–299/mo per seat, $1,548–3,588/yearUp to 10 competitorsDashboard loginAPI available but dashboard-first
Semrush Backlink Gap ($139.95/mo)$139.95–499.95/mo per seatUp to 4 competitors onlyDashboard loginAPI available but dashboard-first
Moz Link Intersect ($99/mo)$99–599/mo (Moz Standard+)Up to 5 competitorsDashboard loginNo MCP integration
SE Ranking Gap Analyzer ($159/mo)$159/mo for Core, $299+ EnterpriseVaries by planDashboard or APIAPI but credit system opaque
DataForSEO Link Gap API ($0.10 per domain pair)$0.10 per domain pair + base costUp to 5 competitorsREST API onlyREST-only, no MCP
LocalSEOData Backlink Gap API$0.05 per analysis (10 credits), no seatsUp to 5 competitorsAPI key + 1-line MCP configNative MCP + REST, agent-first
▌ Connect in 60 seconds

Use it from your agent

Two integration surfaces: MCP for clients that speak MCP, REST API for everything else.

Direct MCP integration

Drop-in support in Claude Desktop, OpenClaw, Hermes Agent, and any MCP-aware client.

Add to your client's MCP config (e.g. claude_desktop_config.json):

{
  "mcpServers": {
    "localseodata": {
      "url": "https://mcp.localseodata.com",
      "headers": {
        "Authorization": "Bearer sk_live_..."
      }
    }
  }
}

REST API

For Perplexity Computer, ChatGPT Custom GPTs, custom agents, and any platform that calls REST endpoints directly.

Base URL:

api.localseodata.com

See the docs for endpoint reference and auth.

▌ Quickstart

Your first call in three lines

Two parameters: `your_domain` (your site) and `competitor_domains` (array of 1-5 competitor domains). Optional: `limit` to cap results (default 50). One call returns all gap opportunities with domain rank for each referring site. One call = 10 credits (~$0.05).

terminal · curl
POST /v1/backlinks/gap
curl -X POST https://api.localseodata.com/v1/backlinks/gap \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "your_domain": "abcplumbing.com",
    "competitor_domains": ["competitor1.com", "competitor2.com"],
    "limit": 20
  }'
Full endpoint reference → · Get an API key →
▌ Pricing for this endpoint

$0.05 per analysis (up to 5 competitors)

10 credits per backlink gap call. Free tier on signup includes 50 credits (5 gap analyses). Monthly plans start at $19 and never expire. No per-seat fees, no competitor caps.

Free tier
5
backlink gap analyses on signup (50 credits)
Starter · $19/mo
380
gap analyses/mo at this rate
Per-analysis cost
$0.05
or 10 credits (up to 5 competitors)
▌ FAQ

Common questions

What is the Backlink Gap API?+
A REST endpoint that compares your domain's backlink profile against 1-5 competitor domains and returns a list of referring sites that link to your competitors but not to you. Those are your best link-building targets because they already link to similar businesses. One call returns all gaps with domain rank (authority score) for each opportunity. The endpoint is POST /v1/backlinks/gap; one call costs 10 credits (~$0.05). This is the data layer underneath outreach targeting, opportunity prioritization, and competitive link intelligence.
How many competitors can I compare against?+
Up to 5 competitors per call. If you want to analyze a larger competitive set (say, 10 competitors), you can split into two calls: 5 competitors vs your domain, then another 5. Most workflows focus on your top 2-3 competitors anyway — they're the ones with the link profile you want to match. Comparing against 5 captures your full local competitive set in a single call.
How does this compare to Ahrefs Link Intersect or Semrush Backlink Gap?+
All three tools do the same thing: show you domains that link to competitors but not to you. The difference is the business model. Ahrefs charges $129–299/mo per seat and lets you analyze up to 10 competitors per analysis but requires a dashboard login. Semrush charges $139.95–499.95/mo per seat but caps you at only 4 competitors. Moz charges $99–599/mo per seat for 5 competitors. With us, you pay $0.05 per analysis (10 credits), no per-seat fees, and you support up to 5 competitors. For agencies managing 5+ client sites, or consultants doing a gap analysis per prospect, our per-call pricing wins dramatically. For teams logging into a dashboard daily, Ahrefs/Semrush may feel more integrated to your workflow.
Where does the data come from?+
DataForSEO, our upstream provider for most SERP and authority endpoints. DataForSEO operates a massive web crawler that continuously indexes backlinks. The backlink gap API chains their backlink index data: we query their referring domains for your domain, query their referring domains for each competitor, then diff the sets to find which refer to competitors but not to you. This is the same data foundation Ahrefs, Semrush, SE Ranking, and Moz all use — they just package it through dashboards at $99–300/mo. We provide the same diff operation at $0.05 per call.
How fresh is the backlink gap data?+
Backlink data refreshes weekly. When you call the endpoint, you get the latest snapshot from the weekly crawl. Domain rank scores refresh monthly. This is slightly slower than Ahrefs (which updates daily) but standard for strategic link analysis and opportunity planning. For day-to-day link velocity tracking or real-time alerts, you'd want a monitoring tool like Monitor Backlinks; for planning quarterly link campaigns, monthly gap analyses, or competitive benchmarking, weekly is appropriate.
Can I filter results by domain authority or link type?+
Yes, domain rank filtering is built in. Set limit to cap your results and you'll get the top opportunities first (ranked by domain authority, highest to lowest). You can also pair this with the Backlinks API to pull the full link profile for each gap domain — then filter further by dofollow/nofollow, anchor text, or link velocity in your agent logic. The gap API gives you the opportunities; the Backlinks API gives you the details to prioritize.
Can my AI agent use this directly?+
Yes, two ways. MCP: Add Local SEO Data to your claude_desktop_config.json (or any MCP-compatible client like OpenClaw or Hermes Agent), and Claude calls this endpoint from your prompt without you writing integration code. You just say 'find link gaps for my site vs my competitors' and it happens. REST: Any agent that can make HTTPS calls (ChatGPT Custom GPTs, Perplexity Computer, custom Python agents) hits api.localseodata.com with Authorization: Bearer sk_live_.... The agent receives the gap list and can reason about it — sorting by domain rank, filtering for local directories, flagging quick wins.
What does it cost?+
$0.05 per backlink gap analysis (10 credits). One analysis compares your domain against up to 5 competitors. If you run 100 analyses per month, that's $5. Most agencies run 1-2 gap analyses per client per quarter — so 12 clients × 2 analyses/quarter = 24 analyses/year = $1.20 in API costs. Compare that to a $129/mo Ahrefs subscription (even if you use 10% of it): $1,548/year for basic access. The per-call pricing means you only pay for what you use. For small agencies or solo consultants doing 2-3 gap analyses per month, the math heavily favors the API.
Does this pair with the Backlinks API?+
Yes, and this is the power of the modular API model. Run a gap analysis to identify opportunities, then run Backlinks API calls on the top 5-10 gap domains to pull their full link profiles. Now you know not just 'they link to your competitor' but 'how many backlinks, from what sources, when did they acquire them, what's the spam score.' Use that enriched data to prioritize your outreach. Most workflows chain both: gap → identify targets → backlinks summary → rank by quality → build outreach list.
What changed in 2026 that made this category exist?+
Two things. First, MCP (Model Context Protocol) became standard in late 2024 and went mainstream through 2025. It let agents call external APIs without bespoke integration work. The moment that happened, link research flipped from a dashboard-driven workflow ('log in to Ahrefs, click around') to an agent-driven workflow ('my Claude instance runs gap analysis on all clients, ranks by opportunity, and shows me the targets'). Second, link gap analysis is now a 10-year-old category (Ahrefs Link Intersect has been around since 2014) — it's fully mature and the value is well understood. The remaining innovation is distribution: unbundle the data layer from the SaaS dashboard and expose it as a per-call API. That's what we did.
Can I use this to analyze my own domain plus a large competitive set?+
Yes. The endpoint compares one of your domains (or a prospect's domain, or an acquisition target) against up to 5 competitors. If you're an agency with a bunch of clients, you'd typically run one analysis per client per quarter — client domain vs. their top 2-3 local competitors. That's straightforward. If you're doing exhaustive competitive mapping (comparing 15 competitors against each other), you'd need multiple calls. But most workflows are focused: 'my client vs. their realistic competition.' Start there.
How do I prioritize which gap opportunities to target?+
Three criteria: (1) Domain rank — higher is better, limit yourself to rank >50 for serious outreach. (2) Competition frequency — if 3 out of 5 competitors all have links from the same domain, it's a higher-confidence target. (3) Relevance — local chambers, directories, and association sites are easier to get links from than publications or blogs. Filter for those first. Pair the gap results with the Backlinks API to add (4) Link velocity — sites that are rapidly adding new links to your space are more likely to link to you too.
What's a 'referring domain'?+
A unique domain that links to your site (or your competitor's site). If domain.com has 100 backlinks pointing to competitor1.com, that's 100 backlinks from 1 referring domain. The gap API returns the unique referring domains you're missing — the actual list of sites to target for outreach. Most link-building campaigns focus on referring domain count (diversity) rather than raw backlink count, because Google cares about how many different sites link to you, not how many total links you have.
▌ Related endpoints

Often used in the same agent prompt

POST /v1/backlinks/summary
Backlinks API

Get backlink counts, referring domains, domain rank, and spam score for any site.

POST /v1/report/competitor-gap
Competitor Gap API

Rankings, reviews, and links vs your local competitors. Composite.

GET /v1/keywords/site
Keywords for Site API

What keywords a competitor ranks for. Find their link targets.

POST /v1/pages/audit
Page Audit API

On-page SEO audit, Core Web Vitals, schema markup.

Build your first gap analysis in 60 seconds.

50 free credits on signup. Compare your domain against competitors in your first agent prompt. Get a prioritized outreach list instead of a spreadsheet export.

Start FreeRead the docs
▌ MADE FOR THE NEW LOCAL SEO STACK