Backlink Checker API — Referring Domains, Competitor Gap & Backlink Profile · Ahrefs / Semrush Alternative

Enter a domain, get its full backlink profile via API — total backlinks, referring domains, spam score, and the competitor backlink gap: the domains that link to your rivals but not to you. Pay per result, no $99–$199/month subscription, no contract. Native backlink-index data via API — not a fragile UI scraper.

Coverage on par with Ahrefs — measured, not claimed. In side-by-side tests our referring-domain coverage matched or beat Ahrefs: an established site returned 1,737 referring domains vs Ahrefs' 1,600; a brand-new site 43 vs 32. You get a credible backlink index at a fraction of a tool subscription. (We don't reproduce Ahrefs' proprietary DR score — see FAQ.)

Built for link builders, SEO & PR agencies, sales / lead-gen teams, and developers wiring backlink data into pipelines via API or MCP.

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⚡ Quick start — 30 seconds

Click Try for free. The default input runs a real backlink summary on a live domain — actual JSON in seconds. Then swap in your own:

{ "domains": ["monday.com"], "mode": "summary" }

Sample output (real run, trimmed):

{
  "mode": "summary",
  "target": "monday.com",
  "rank": 644,
  "backlinks": 8975219,
  "referring_domains": 72896,
  "referring_main_domains": 63603,
  "referring_domains_nofollow": 9683,
  "broken_backlinks": 138276,
  "backlinks_spam_score": 19,
  "first_seen": "2019-01-15"
}

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🎯 Five modes

mode	Input	What you get
check 💸	domains (up to 100)	cheapest way in — $0.015/domain. One row per domain: rank, backlinks, referring domains, spam score, broken links
summary (default)	domains	full profile: rank, backlinks, referring domains (total / main / nofollow), broken backlinks, spam score, first seen
referring_domains	domains, limit	ranked list — each { domain, rank, backlinks, spam score, first seen }
competitor_gap ⭐	domains, competitors, limit	domains that link to your competitors but not to you — your ready-made link-building target list
monitor 🔔	domains, monitorLabel	new & lost referring domains since your last run — you're only charged when something changed

competitor_gap is the one no free tool gives you. Drop in 2–3 rivals and get the exact referring domains you're missing — the highest-intent link-prospecting list there is.

Start with check. It's the cheapest lookup on the Store for native-index backlink data, it takes up to 100 domains in one run, and it costs nothing for domains the index has never seen.

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🚀 Input

field	type	default	notes
domains	string[]	— (required)	target domains (up to 100); auto-normalized (scheme/path/www. stripped, IDN→punycode, lowercased) and deduped
mode	enum	summary	check | summary | referring_domains | competitor_gap | monitor
competitors	string[]	—	required for competitor_gap; rival domains
limit	int (1–1000)	100	rows for the list modes and monitor (ignored by summary and check)
includeSubdomains	bool	true	count subdomains toward the target
monitorLabel	string	auto	monitor only — names the watchlist so each keeps its own history

// cheapest check — 4 domains for $0.06 + $0.005 start
{ "domains": ["monday.com", "asana.com", "clickup.com", "notion.so"], "mode": "check" }

// referring domains — top 50 by rank
{ "domains": ["monday.com"], "mode": "referring_domains", "limit": 50 }

// competitor gap — who links to asana & clickup but not monday
{ "domains": ["monday.com"], "mode": "competitor_gap",
  "competitors": ["asana.com", "clickup.com"], "limit": 100 }

// monitoring — schedule weekly; billed only on runs that find changes
{ "domains": ["monday.com"], "mode": "monitor", "monitorLabel": "client-monday" }

📊 Output

One dataset item per target domain (except monitor, which emits one row per link change):

• check → { target, found, domain_rank, total_backlinks, referring_domains, spam_score, broken_backlinks, first_seen }
• summary → { target, rank, backlinks, referring_domains, referring_main_domains, referring_domains_nofollow, broken_backlinks, backlinks_spam_score, first_seen }
• referring_domains → { target, count, referring_domains_list: [{ domain, rank, backlinks, backlinks_spam_score, first_seen }] }
• competitor_gap → { target, competitors, gap_count, gap: [{ domain, rank, links_to[] }] }
• monitor → { target, change: "new" | "lost", domain, rank, backlinks, first_seen, lost_date }

Export as JSON / CSV / Excel, or pull live via the Apify API (run-sync-get-dataset-items).

💰 Pricing — pay per result, flat per report

You pay per domain, not per row — same price whether you pull 20 rows or 1,000.

event	price / domain	when
actor-start	$0.005	once per run, after input validation
domain-check	$0.015	per domain returned by a check run — domains not in the index are free
monitor-changes	$0.10	per domain per run, only when that domain actually changed
domain-summary	$0.15	after a successful summary
referring-domains-report	$0.20	after a successful referring-domains list (any limit)
competitor-gap-report	$0.25	after a successful competitor-gap report (any limit)

Charged only after data is delivered — failed or empty calls bill nothing beyond actor-start. A per-run cost cap (MAX_RUN_COST_USD, default $5) stops the run before overspend.

Examples

• Check 20 domains: $0.005 + 20 × $0.015 = $0.305.
• Competitor gap vs 2 rivals (top 100 prospects): $0.005 + $0.25 = $0.255 — the same workflow in Ahrefs/Semrush needs a $99–$199/month seat.
• Weekly monitoring on 5 domains, 1 of which changed: $0.005 + $0.10 = $0.105. A quiet week costs $0.005.

🎁 Start free

The free Apify plan runs 3 domain checks per run — no card, no trial clock. New Apify accounts also get $5 in platform credit, which is roughly 300 domain checks at $0.015 each.

Prefer the full profile? Free runs can also do 1 domain in summary mode, showing your real referring-domain count, broken links, and spam score. Popular domains return instantly from a built-in preview cache; any other domain gets a real live summary so you can preview your own site. Ranked referring-domain lists, competitor gap, and monitoring need a paid plan.

🔔 Monitor new & lost backlinks — pay only when something changes

Point monitor at your domains and schedule it. The first run records a baseline (billed as a domain check, since there's nothing to compare against yet). Every run after that returns only what changed — referring domains gained and lost since the previous run.

The billing is the part nobody else offers: a run that finds no changes charges nothing beyond actor-start ($0.005). You pay $0.10 per domain only on runs that actually have news. Watching 10 client domains weekly costs you $0.005 on a quiet week and $0.105 on a week where one of them picked up links.

{ "domains": ["yoursite.com", "clientsite.com"],
  "mode": "monitor",
  "monitorLabel": "weekly-clients" }

Use monitorLabel to keep separate watchlists — a weekly-clients label and a monthly-prospects label track the same domain independently, each with its own history. Leave it empty and the label is derived from the domain set, so re-running the same list just continues it.

Set it up: open the Schedules tab in Apify, point a weekly (or monthly) schedule at this Actor, and pipe the dataset to Slack, email, or a sheet via Apify integrations. Lost a high-authority link? You'll know within the week instead of at the next audit.

🆚 How it compares

vs. Ahrefs / Semrush / Moz — no $99–$199/month subscription; pay per domain checked. API-first JSON straight into your sheet, CRM, n8n/Make/Zapier, or AI agent. Referring-domain coverage on par (measured). Trade-off: we don't reproduce Ahrefs' proprietary DR — we return a 0–1000 domain rank + backlink spam score.

vs. other Apify backlink actors — most scrape the Ahrefs/Semrush UI: fragile (break on UI change), ToS-risky, only as available as the SaaS login. This actor uses a native data API — stable, no scraping, no proxy roulette — and adds a value layer (competitor gap, spam signal, clean typed output, free preview).

vs. raw data-API providers — no monthly minimum commitment, no API-key management, no per-endpoint billing math. Pay per result, scale to zero.

🧭 Who it's for

• Link builders / SEO agencies — competitor_gap = instant prospecting list; referring_domains = profile audit.
• Content & PR teams — see who links to the competition, pitch the same outlets.
• Sales / lead-gen — a rival's referring domains are warm outreach signals.
• Developers & AI agents — backlink data as a clean JSON API / MCP tool, billed per call.

🔌 API & integrations

Run from the Apify API (incl. run-sync-get-dataset-items for a single request/response call), official JS / Python clients, CLI, or any HTTP client — see the API tab. Pipe results to Google Sheets, Slack, n8n, Make, Zapier via Apify integrations.

🤖 Use with AI agents & LLM workflows

Ask Claude or ChatGPT to check a domain mid-conversation. This Actor is reachable through the Apify MCP server (mcp.apify.com), so any MCP-capable client — Claude Desktop, Claude Code, Cursor, ChatGPT — can call it as a tool. "How many referring domains does competitor.com have, and which ones do we not have?" becomes a single turn, with real index data instead of a guess. It runs under limited permissions (see the FAQ), so there's no full-account approval step.

No-code automation — n8n, Make, Zapier. A typical flow: Schedule trigger → run this Actor (mode: "monitor") → read the dataset JSON → branch on change. Route "lost" rows to a Slack channel as a reclaim task, push "new" rows to a CRM or a client report, and append everything to a Google Sheet for the monthly deck. Because monitoring only bills on runs with changes, leaving that schedule on all year is cheap.

LLM reporting — turn the gap report into outreach. Run mode: "competitor_gap", then feed the dataset straight to ChatGPT or Claude: "Here are 100 domains linking to my competitors but not to me, with rank and spam score. Group them by likely site type, drop anything spammy, and draft a one-paragraph outreach angle for the top 20." You get a prioritized prospect list and first-draft pitches in one pass — the gap data is the part an LLM can't invent.

Plain API. Any agent framework that can make an HTTP call (LangChain, LlamaIndex, a custom tool loop) can hit the Apify API endpoint directly and get typed JSON back — no scraping logic, no proxy handling, no HTML parsing on your side.

🛡️ Legal & compliance

Uses a licensed native backlink data API. Public link-graph data only — no login-walled or personal data. ToS-safe (no identical-request hammering; built-in run cache).

🧰 FAQ

Is the coverage as good as Ahrefs? On referring domains, yes in our tests (1,737 vs 1,600 established; 43 vs 32 new). Backlink indexes never match exactly — we surface a credible, native index at pay-per-result pricing.

Do you return Domain Rating (DR)? No — DR is Ahrefs' proprietary score. We return a domain rank (0–1000) + backlink spam score for relative authority/quality.

How am I billed? Per result, after delivery (see Pricing). Free / failed / empty calls don't bill beyond actor-start. A per-run cost cap prevents surprises.

Where does the data come from? A licensed, enterprise-grade backlink-data API — not a UI scraper. Stable, no proxies.

What's the cheapest way to check a domain? mode: "check" at $0.015 per domain — rank, backlinks, referring domains, spam score, and broken links, up to 100 domains in one run. Domains the index has never seen come back marked found: false and cost nothing. On the free plan you get 3 checks per run without spending anything.

Can I track new and lost backlinks? Yes — mode: "monitor". The first run sets a baseline, and every run after returns only the referring domains gained or lost since then. You're charged $0.10 per domain only on runs that actually find changes, so a weekly schedule costs $0.005 in quiet weeks. Use monitorLabel to keep separate watchlists (per client, per cadence). See Monitor new & lost backlinks.

Is it really free to run when nothing changed? Yes. In monitor mode the change-detection fee fires per domain per run, and only when that domain's diff is non-empty. A run that finds nothing costs you the $0.005 actor start and nothing else.

What is a backlink? A backlink is a link from another website to yours. Search engines treat them as votes of trust, so a profile of quality backlinks from many distinct domains is one of the strongest off-page ranking signals. This actor returns any domain's backlinks, the referring domains behind them, and a competitor gap.

What's the difference between a backlink and a referring domain? A backlink is a single link; a referring domain is a unique website linking to you. One domain can give you 10,000 backlinks (e.g. a sitewide footer link) but it still counts as one referring domain — which is why we surface referring domains as a first-class metric.

Why look at referring domains instead of total backlink count? Raw backlink counts are inflated by sitewide and templated links. 250k backlinks from 1,700 referring domains is a far weaker profile than 250k from 50,000 domains. Compare on referring domains to judge real authority and to find link-building gaps versus competitors.

Is this safe for AI agents to run? Yes. It runs under limited permissions — it only does its job (queries the backlink API and writes your dataset) and never touches the rest of your Apify account, so there's no full-permission approval step. Run it from any AI agent or IDE via the Apify MCP server (mcp.apify.com).

🗺️ Roadmap

Shipped in v0.2: the $0.015 check mode (bulk, up to 100 domains) and monitor mode for new/lost referring domains with pay-only-on-changes billing. Next: anchor-text breakdown, per-backlink (not just per-domain) monitoring, disavow-list export, and Slack/email alert templates for scheduled monitor runs.

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Found this useful? If it replaced part of an Ahrefs or Semrush subscription for you, a ⭐ review helps other SEOs find it — and bookmarking the Actor keeps it one click away in your Apify console. Hit a rough edge or need a mode that isn't here? Open an issue and it gets read.

🔗 Related Actors

• Competitor Keyword Research — any site's ranked keywords.
• Keyword Metrics Pro — keyword volume, CPC & trend.
• AI Keyword Clustering Tool — topical authority map.
• Website Traffic & Domain Authority — domain traffic & authority rank in bulk (SEO Similarweb alternative).

🏷️ Keywords

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🤝 Built by

doesaiknow — semantic-SEO & LLM-search APIs on Apify Store. Pay-per-result, no subscription, MCP-ready. More tools:

• Keyword Search Volume API — Google + Bing search volume, CPC & 12-month trends, bulk.
• AI Keyword Clustering Tool — cluster up to 1,000 keywords into a SERP-validated topical map.
• AI Brand Visibility Tracker — see where your brand shows up in ChatGPT, Perplexity & Gemini answers.