Somebody sends you a list of possible link partners, a client asks whether their new domain is “strong”, or you want to see whether an old domain you are about to buy was ever linked from anywhere. You need a quick, comparable number for how well-linked a domain is — without signing up for an SEO suite and without pretending that one number explains search rankings.
The Website Authority Checker looks up up to ten domains at once in the Open PageRank dataset and shows each domain’s score on a 0–10 scale, its global rank, the provider’s count of referring domains and, where available, a monthly score history. It shows the provider’s values unchanged, with the data release date, and it states clearly when a value is missing, cached or not available.
What is website authority?
In simple terms
Website authority is a rough measure of how many other websites link to a domain, and how well-linked those websites are themselves. A domain linked from thousands of established sites scores high; a domain that almost nobody links to scores low or does not appear at all. It is a popularity measure based on links, not a quality rating and not a ranking forecast.
Technical background
The idea comes from PageRank, the link-analysis algorithm described by Google’s founders in the late 1990s: the web is treated as a graph, and a link from one node to another passes a share of the linking node’s importance. Importance is computed iteratively until values stabilize, so a link from a well-linked site is worth more than a link from an obscure one.
Open PageRank applies a PageRank-style calculation at the domain level to the link graph published by Common Crawl, an open web crawl. The results are scaled to 0–10 (with up to two decimals) and sorted into a global rank. Because the input is a crawl, the data has natural gaps: sites that Common Crawl did not reach, or that are linked only from pages it did not crawl, may be missing or under-scored. Months without a new Common Crawl release are interpolated by the provider, which the checker marks as “estimated”.
None of the commercial “authority” metrics (Moz Domain Authority, Ahrefs Domain Rating, and others) are interchangeable with Open PageRank. They use different crawls, different formulas and different scales.
Why use a website authority checker?
- Vetting link sources and partners. A guest-post offer from a domain that is “not ranked” or scores near 0 is very unlikely to carry much link value.
- Checking an expiring or second-hand domain. The score history shows whether the domain was once well-linked and has declined, or never had links at all.
- Comparing competitors. Entering several domains in one check produces a comparison table sorted by score, using the same data release for all.
- Tracking the effect of a site migration. After moving to a new domain, the old and new domains can be compared over several data releases (combine this with the Redirect Checker to make sure old URLs actually forward).
- Sanity-checking claims. If a vendor promises “high-authority links”, you can check the domains independently.
Who should use it?
- SEO specialists and content marketers comparing domains or evaluating link opportunities.
- Webmasters and site owners who want a neutral, free reference number for their own domain.
- Agencies preparing a quick overview for a client before a deeper audit.
- Anyone buying a domain who wants to know whether it has a link history.
It is not meant for monitoring day-to-day changes; the data moves with provider releases, not daily.
How the website authority checker works
- Input normalization in your browser. Each line (or comma-, space- or semicolon-separated entry) is cleaned up: the protocol, path, query string, fragment, port and any credentials are removed, a trailing dot is dropped, the name is lower-cased, internationalized names are converted to punycode (for example
bücher.debecomesxn--bcher-kva.de) and a leadingwww.is removed. IP addresses, non-web schemes such asftp://ormailto:, single-label names and reserved names are rejected with an explanation. Duplicates are removed, and a “Will check:” line shows exactly what will be sent. At most 10 domains are accepted per check. - Cache lookup on the NetTools.tech server. The server first looks for each domain in a short-lived in-memory cache (24 hours by default). Only answers the provider actually confirmed are cached. Errors are never cached, so a temporary outage can never turn into a stored “not ranked”.
- Provider request. Domains not in the cache are sent in one request to the Open PageRank bulk API, together with a request for score history. The API key stays on the server; your browser never contacts the provider. The provider call has a 10-second timeout and a size limit on the answer. Identical batches requested at the same moment share one provider call.
- Limits. A server-wide daily cap (by default 900 domains per day) protects the shared monthly allowance, and each client may check a burst of 20 domains and then about 30 domains per hour. The general per-client API rate limit applies as well.
- Parsing. The provider’s answer is validated strictly: scores outside 0–10, negative ranks and malformed history points are discarded rather than shown. Each domain gets one of four states — Ranked, Found, no score, Not ranked or No data returned — and request failures (timeouts, rate limits, quota, outages) are shown as errors with no scores at all.
The result for each domain records whether it was a live lookup or a cached result, and when the provider data was originally retrieved.
How to use the NetTools.tech Website Authority Checker
- Open the Website Authority Checker.
- In Domains or website URLs, enter one domain per line or separate them with commas, for example
example.comandhttps://www.example.org/page. You can paste full URLs; they are reduced to the domain. The Try: buttons fill in a single domain, a URL, or three domains for comparison. - Check the Will check: line under the field. It lists the normalized domains and how many duplicates were removed. Invalid entries are reported before anything is sent.
- Press Check authority (or Ctrl+Enter / Cmd+Enter in the field).
- Read the result cards, and — when you checked more than one domain — the Comparison table and the Score history chart.
- Use Copy summary on a card for a plain-text summary, or the export bar to download CSV or JSON, copy everything, or print a report including the history chart.
Understanding the results
| Result | Meaning | What to look for |
|---|---|---|
| Open PageRank score | Link-based score on a 0–10 scale, up to two decimals, exactly as returned by the provider | Compare with similar sites from the same data release; small differences in the second decimal are not meaningful |
| Global rank | The domain’s position by that score, 1 = highest | Only shown when the provider reports one; “Not available” means no value was supplied, not a rank of zero |
| Referring domains | The provider’s own authority-weighted count of linking domains | It is not a complete backlink count and will not match other tools |
| Status: Ranked | The provider found the domain and returned a score — including 0 | A score of 0 means “known, but very little link authority” |
| Status: Found, no score | The provider knows the domain but returned no usable score | Try again after the next data release |
| Status: Not ranked | The provider explicitly reported the domain as not found | Typical for new or rarely linked sites; not a penalty |
| Status: No data returned | The provider’s answer did not mention the domain | Usually temporary; check again later |
| Live lookup / Cached result | Whether the answer came directly from the provider or from the NetTools.tech cache | Cached results keep their original retrieval time |
| Data release | The provider’s release date for the data | Scores only change between releases |
| Subdomains | Host-level scores, ranks and statuses when the provider returns them | Useful when a platform hosts many sites under one domain |
| Score history | Monthly scores; solid line = measured, dashed = interpolated by the provider | Range buttons (1Y, 3Y, 5Y, All), a “Full 0–10 scale” option, legend toggles and a data table |
| History summary | “History since …”, the 12-month change and the peak month | A 12-month change is only shown when that month exists in the history |
If you entered a subdomain or a URL, the card shows the reduced domain with “Checked as …” listing your original input.
Example: comparing three domains
You enter:
example.com
https://www.example.org/blog/
example.netThe Will check: line shows example.com, example.org, example.net — the https://www. prefix and /blog/ path were removed. After Check authority, a comparison table sorts the three by score, and each domain gets a card. The Copy summary text for one card has this shape (the numbers here are illustrative, not real provider data):
example.org — Ranked
Open PageRank score: 5.2 / 10
Rank: #12,345
Referring domains (provider): 1,234
Source: Open PageRank, data release 2026-09-01 (live lookup, 2026-10-17T09:12:00.000Z)If one of the three had come back as “Not ranked”, its card would show “—” instead of a score, with the note that this is typical for new or rarely linked sites. If the provider had been unreachable, none of the three would show a score; instead you would see an error message stating explicitly that this is not a “not ranked” result.
Common use cases
- Shortlisting outreach targets: paste ten candidate domains and discard those that are not ranked.
- Domain purchase due diligence: look at the history chart for a sudden collapse, which can indicate the site was abandoned or lost its links.
- Client reporting: export CSV or JSON with source and data release columns so the numbers can be traced later.
- Platform vs. own domain: compare a blog on a hosted platform subdomain with a self-hosted domain using the Subdomains table.
- Post-migration review: watch old and new domains across releases while checking redirects and broken links on the new site with the Broken Link Checker.
Troubleshooting
“IP addresses have no website authority score”
You entered an IPv4 or IPv6 address. Enter the domain name the site uses instead.
An entry is rejected as invalid
Single-label names (localhost), reserved names such as router.local, names with spaces or invalid characters, and non-web schemes are refused. Fix the entry or remove it; nothing is sent until every entry is valid.
“Check at most 10 domains at a time”
More than ten unique domains remain after normalization. Split the list into several checks.
“Rate limit reached” or “daily lookup limit”
Either your client has used its hourly allowance, the server-wide daily cap has been reached, or the provider itself is rate limiting. Wait as indicated in the message. When the provider’s monthly allowance is used up, the message says lookups resume when it resets on the 1st of the next month.
“Not configured” or “Data provider error”
The server could not use the provider (missing or rejected API key, provider outage, invalid answer). No scores are shown. Try again later; this says nothing about your domain.
The score did not change after I gained many links
The provider recomputes scores per data release, from Common Crawl data that may lag behind. New links also need to be discovered by the crawl. Check again after the next release date.
Common mistakes
- Treating the score as a ranking prediction. It measures domain-level link popularity, not relevance, content quality or page-level performance.
- Comparing numbers across vendors. An Open PageRank 6 and a Moz DA 60 are not comparable.
- Reading “Not ranked” as a penalty. It only means the domain is absent from the provider’s link data.
- Over-interpreting small differences. A 0.05 difference between two domains is noise for most decisions.
- Checking daily. Values change with provider releases; a cached result within a day is expected.
- Assuming the rank is the same as traffic rank. The global rank is a position by link score, not by visitors.
Limitations
- The data comes from one provider, computed from Common Crawl’s link graph. Sites or links that the crawl did not see are missing or under-scored.
- Scores are domain-level. They tell you nothing about a specific page, keyword or country.
- History months marked as estimated are interpolated by the provider, not measured.
- Referring domains are the provider’s weighted count and cannot be audited from the checker; no list of linking domains is shown.
- Subdomain inputs are reduced to the registered domain by the provider; host-level values appear only when the provider supplies them.
- Results may be up to a day old (cache), and availability depends on the provider and the shared daily allowance.
- The checker cannot detect link schemes, paid links or penalties.
Security & privacy
The domains you enter are sent from your browser to the NetTools.tech server and from there to Open PageRank, the data provider. Your browser never contacts the provider directly, and the provider never sees your IP address in the request. NetTools.tech keeps results only in a short-lived in-memory cache keyed by domain; it does not build a history of who checked what. The provider’s API key is held on the server and is never sent to the browser.
Enter only domain names or public URLs. Do not paste URLs containing tokens, session IDs or credentials; the checker strips paths and credentials before sending, but there is no reason to include them in the first place. See the privacy policy for the list of third parties.
Related tools
- Meta Tag Analyzer — check titles, descriptions and canonical tags on the pages that earn links. Guide: Meta Tag Analyzer guide.
- Redirect Checker — make sure old domains and URLs forward link value with permanent redirects. Guide: Redirect Checker guide.
- Broken Link Checker — find dead links on your own site. Guide: Broken Link Checker guide.
- Robots.txt Checker — confirm crawlers can reach the pages you want discovered.
- WHOIS Lookup — see registration dates when evaluating a domain’s history.
- Overview of the category: Web & SEO tools guide.
Summary
The Website Authority Checker shows Open PageRank’s link-based score (0–10), global rank, referring-domain count and monthly history for up to ten domains, with the source, data release and cache status on every result. It is useful for comparing domains and spotting link history, but it measures link popularity from one crawl-based dataset and does not predict search rankings. Missing data, limits and provider errors are always shown as such, never as a score.
Frequently asked questions
Is the Open PageRank score the same as Google PageRank?
No. Google stopped publishing PageRank values publicly in 2016, and nobody outside Google can see the internal figures. Open PageRank is an independent metric computed from the openly published Common Crawl link graph; it uses a PageRank-style idea but its own data and scale.
Is the score the same as Moz Domain Authority or Ahrefs Domain Rating?
No. Each vendor crawls its own link data and uses its own formula and scale, so a 5 in one system says nothing about the value in another. Compare sites using the same metric from the same provider and the same data release.
Does a higher authority score mean better Google rankings?
Not directly. The score estimates link popularity at domain level, which is only one of many signals search engines use, and it says nothing about a specific page, query or country. Use it to compare sites with each other, not to predict search positions.
Why is my domain shown as “Not ranked”?
The provider reported that the domain is not in its link data. This is normal for new, small or rarely linked sites and is not a penalty or a sign of a problem. A score of 0 is different: the domain is known but has very little link authority.
How often does the score change?
The score changes when Open PageRank publishes a new data release, which is shown with each result as the data release date. Checking every day will not show daily movement, and NetTools.tech may answer from a cache for up to a day, marked as a cached result.
Why does the checker refuse IP addresses?
Authority is computed for registered domain names, so an IP address has no score. Enter the domain the site is served under; the checker removes protocols, paths, ports and a leading www. automatically.
Why do I get a daily limit or rate limit message?
Lookups use a shared provider allowance, so NetTools.tech caps the number of domains it sends to Open PageRank per day across all users, and each client can check a limited number of domains per hour. When a limit is hit no scores are shown at all; it is never reported as “not ranked”.
Can I check a subdomain such as blog.example.com?
Yes, you can enter it, but the provider reduces it to the registered domain and the main result is for that domain; the card shows that it was “checked as” your input. When the provider returns host-level data, a Subdomains table lists scores for individual hosts.