No single tool has a provably "largest" link index, and the vendors' own claims are the only numbers most of us get. Ahrefs, Semrush, Majestic and others each publish big figures, but they count differently (links, pages, referring domains, fresh vs. historical). The practical answer is to test a few tools against your own sites.
Why index size is hard to compare
- Different units. One vendor may quote total links, another referring domains. Those figures aren't comparable.
- Freshness vs. history. A tool that keeps old, dead links will look bigger than one that prunes them, but it may not be more useful.
- Self-reported numbers. Vendors measure their own indexes. Independent audits are rare, so treat headline figures as marketing until you verify them.
- Coverage varies by niche. A tool can be strong on large news sites and thin on small local ones.
A quick test you can run yourself
- Pick three domains: your own, a close competitor, and a site you know well, so you can spot missing links.
- Export referring domains from each tool you're considering (free trials or limited plans often allow this; confirm on each official site).
- Merge the lists in a spreadsheet and dedupe by domain.
- Count how many unique domains each tool found that the others missed, and how many of those are live and relevant.
- Check a sample of "found only by one tool" links by hand. This shows whether extra coverage is real or stale.
Recommended for youBest Backrefs Alternatives: Top Backlink Tools ComparedWhat the comparison usually shows
| What to check | Why it matters |
|---|---|
| Unique live referring domains | Shows real coverage, not inflated totals |
| Freshness of discovered links | Stale data wastes outreach time |
| Export limits | Caps can matter more than index size |
| Price for your usage | A bigger index isn't worth it if you can't afford the plan |
Expect trade-offs. Combining two tools often gives the fullest picture, but it costs more. For a small site, one tool's index is usually enough. For client work, a second source for audits can be worth it. Whatever you choose, confirm current limits and pricing on the vendor's official site.
Related
For direct comparisons, see Backrefs vs Ahrefs, Backrefs vs Semrush, and Backrefs vs Majestic and Moz Link Explorer: Index, Metrics and Value. If you're deciding what to buy, try Backrefs vs Ahrefs vs Semrush: Which Backlink Tool to Buy or Backlink Tool Pricing Compared. You can also browse Backrefs Alternatives & Comparisons.
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