AhrefsSiteAudit
Ahrefs Pte. Ltd. operates AhrefsSiteAudit, which crawls and renders pages for its Site Audit tool to find technical and on-page SEO issues at an Ahrefs user's request. Its robots.txt token is AhrefsSiteAudit; it obeys robots.txt by default, though verified owners can override that on their own sites. Verification uses published IP ranges or reverse DNS to ahrefs.com or ahrefs.net.
Mozilla/5.0 (compatible; AhrefsSiteAudit/6.1; +http://ahrefs.com/robot/site-audit)What AhrefsSiteAudit does
In logs the crawler identifies as "Mozilla/5.0 (compatible; AhrefsSiteAudit/6.1; +http://ahrefs.com/robot/site-audit)". A second, mobile string is also documented, ending in "Mobile Safari/537.36 (compatible; AhrefsSiteAudit/6.1; +http://ahrefs.com/robot/site-audit)". The URL in the string currently 301-redirects to https://ahrefs.com/robot. Ahrefs says the crawler runs when one of its users audits a site. It renders JavaScript, and Ahrefs says page assets are requested simultaneously during rendering, so expect asset requests alongside the page. Ahrefs' help article says the crawler operates from the USA only.
Allowing AhrefsSiteAudit lets Ahrefs users, including you if you hold an account, run Site Audit against your pages to find broken links, slow performance, security misconfigurations and SEO pitfalls. Blocking it prevents those audits. The default speed limit is 30 URLs per minute at most; verified site owners can crawl their own sites faster. Ahrefs documents that the crawler obeys robots.txt and crawl-delay by default, and that a verified owner can request that it disobey robots.txt or crawl-delay on their own site. Ahrefs also notes that crawl-delay cannot be followed when rendering JavaScript, because the assets are requested simultaneously.
Ahrefs publishes IP ranges at https://api.ahrefs.com/v3/public/crawler-ip-ranges (81 ipv4Prefix entries) and individual addresses at https://api.ahrefs.com/v3/public/crawler-ips (10,350 ip_address entries); both lists are shared with AhrefsBot, so they do not tell the two crawlers apart. Reverse DNS on a genuine request always resolves to a hostname under ahrefs.com or ahrefs.net, so either the IP lists or a DNS check confirms origin. Cloudflare lists AhrefsSiteAudit as a verified good bot.
Operator note. AhrefsSiteAudit is a user-triggered crawler that runs when an Ahrefs user audits a site. The documentation states 'Obeys robots.txt: Yes by default (website owners can request to disobey robots.txt on their sites)' and 'Obeys crawl delay: Yes by default (website owners can request to disobey crawl delay on their sites)', so only verified site owners can allow it to ignore robots.txt on their own sites. A second, mobile user-agent string is documented: 'Mozilla/5.0 (Linux; Android 13) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/151.0.7922.173 Mobile Safari/537.36 (compatible; AhrefsSiteAudit/6.1; +http://ahrefs.com/robot/site-audit)'. It renders JavaScript, and crawl-delay 'cannot be followed when rendering JavaScript' because assets are requested simultaneously; the default speed limit is 30 URLs per minute, verified owners can crawl their own sites faster, and Ahrefs says AhrefsSiteAudit crawls from the USA only.
Controlling AhrefsSiteAudit with robots.txt
Use the token AhrefsSiteAudit in robots.txt. Ahrefs Pte. Ltd. documents limits on how this bot applies robots.txt; see the operator note.
User-agent: AhrefsSiteAudit
Disallow: /User-agent: AhrefsSiteAudit
Allow: /Verifying a request is really AhrefsSiteAudit
Anyone can put AhrefsSiteAudit in a User-Agent header. AhrefsSiteAudit uses the same published IP lists as AhrefsBot: https://api.ahrefs.com/v3/public/crawler-ip-ranges and https://api.ahrefs.com/v3/public/crawler-ips. The reverse DNS suffix of its hostnames is 'always ahrefs.com or ahrefs.net'. It is also listed as a Cloudflare verified 'good' bot.
host <request-ip>
# expect a hostname ending in ahrefs.com or ahrefs.net
host <that-hostname>
# expect it to resolve back to <request-ip>Ahrefs Pte. Ltd. publishes a machine-readable list. Our probe read it on 2026-09-06; the file's own creation time was not stated.
- Prefixes
- 81
- IPv4
- 81
- IPv6
- 0
First entries at fetch time: 5.39.1.224/27, 5.39.109.160/27, 15.235.27.0/24
SHA-256 of the fetched body: 4246eee9407d58fb030ee9f12776f974f628db4b4f91f8111847dd565fc63d45
Common questions
Should I block AhrefsSiteAudit?
Ahrefs says the crawler only runs when an Ahrefs user audits a site and is limited to 30 URLs per minute by default. Blocking it stops Site Audit from analyzing your pages, including audits you might run yourself. If load is the concern, a crawl-delay is honored by default, except while rendering JavaScript.
Does AhrefsSiteAudit run JavaScript?
Yes. Ahrefs documents that AhrefsSiteAudit renders pages, and notes that crawl-delay cannot be followed during rendering because page assets are requested at the same time. Expect requests for those assets alongside the HTML in your logs.
How do I verify AhrefsSiteAudit?
Match the source IP against Ahrefs' public lists at api.ahrefs.com/v3/public/crawler-ip-ranges or crawler-ips, which are shared with AhrefsBot, or reverse-resolve the IP and confirm the hostname is under ahrefs.com or ahrefs.net. Ahrefs says the reverse DNS is always one of those two domains.
Sources
Every fact on this page was checked against Ahrefs Pte. Ltd.'s own documentation, listed below, and re-checked by a second reviewer before publication. Reviewed September 2026.
Related crawlers
This registry documents how operators describe their own bots so site owners can identify and control them. It does not publish third-party IP lists or guess at undocumented behaviour. To see how your own site responds to automated visitors, the bot detection scanner reads a URL's live response and names the protection it finds.