Lighthouse Audit
Operated by Google
Quick Facts
- User-Agent:
- Chrome-Lighthouse
- Category:
- SEO Tools
- Operator:
- Safety:
- Safe
- Blocking Impact:
- Low - No SEO ranking impact
- SEO Impact Score:
- 2/10
- Official docs:
- None published by Google
Reported, not operator documented
Google has not published a crawler page that names Chrome-Lighthouse. It is listed here because an independent primary source does: GitHub (GoogleChrome/lighthouse source). Lighthouse audit runner appends Chrome-Lighthouse to its user agent. It is a testing tool, not a crawler; sites see it when someone runs PageSpeed Insights or a Lighthouse audit.
What that means for you: the Chrome-Lighthouse rule on this page is the best available spelling, but Google has made no statement of purpose, crawl rate or robots.txt compliance. Treat a Chrome-Lighthouse request in your logs as a clue, not proof of who sent it, and add a firewall rule if that traffic matters to you. If the operator publishes documentation, this profile moves to Official docs.
What is Lighthouse Audit?
Lighthouse Audit is a monitoring and validation agent operated by Google. It checks pages, ad destinations, or policy compliance rather than collecting training data. It has no effect on search rankings.
Lighthouse Audit is a monitoring and validation agent operated by Google. It checks pages, ad destinations, or policy compliance rather than collecting training data. It has no effect on search rankings.
Lighthouse Audit uses the user-agent token Chrome-Lighthouse. You can control it via robots.txt, meta tags (noai), or the emerging llms.txt standard. Robots.txt is voluntary; for hard enforcement, combine it with server-level IP blocking.
What happens if you block Lighthouse Audit?
How to block Lighthouse Audit with robots.txt
<code>User-agent: Chrome-Lighthouse</code> - Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.
Is Lighthouse Audit safe to allow?
What does Lighthouse Audit do?
Understanding Lighthouse Audit's purpose helps you decide whether to allow or block it.
- Validates pages, ads, or policy compliance
- Performs automated quality and safety checks
- Does not collect training data
- No impact on search rankings
- Generally safe to allow
Lighthouse Audit in context
Lighthouse Audit is a utility crawler operated by Google. In plain terms, it checks pages for an SEO, uptime or analytics service. Our database files it under SEO tools and ranks it Tier 4, specialist crawlers that matter to particular sites or markets. 19 of the 19 SEO tools in our database share this tier.
Its safety rating is safe and its blocking impact is not documented. So the decision about Lighthouse Audit rests on what you want from Google, not on its behaviour. How we rate safety and impact.
How site owners treat Lighthouse Audit
In our own scan of the Tranco top 10,000 (5,583 valid robots.txt files), 16 files (0.3%) name Chrome-Lighthouse in a User-agent line. That shows site owners treat the token as a real crawler worth a rule. It does not, on its own, prove who operates it.
Does it follow robots.txt?
Lighthouse Audit's operator does not clearly document how it treats robots.txt. Write the Lighthouse Audit rule anyway, then confirm in your logs that its requests stop.
Google crawlers and close alternatives
Lighthouse Audit is one of 32 Google crawlers in our database. A User-agent: Chrome-Lighthouse group controls Lighthouse Audit only; the other Google tokens below need their own lines.
Chrome-Lighthouse: this crawler (Tier 4)AdsBot-Google: Google Ads Quality (Desktop), checks pages for an SEO, uptime or analytics service (Tier 3)AdsBot-Google-Mobile: Google Ads Quality (Mobile), checks pages for an SEO, uptime or analytics service (Tier 3)APIs-Google: APIs-Google, fetches a page when a person asks an assistant or app to open it (Tier 3)FeedFetcher-Google: Google Feed Fetcher, builds a search or answer index (Tier 3)Gemini-Deep-Research: Gemini-Deep-Research, fetches a page when a person asks an assistant or app to open it (Tier 3)Google-Agent: Google Agent (Project Mariner), fetches a page when a person asks an assistant or app to open it (Tier 2)Google-CloudVertexBot: Google Vertex AI, fetches a page when a person asks an assistant or app to open it (Tier 3)Google-CWS: Chrome Web Store Fetcher, checks pages for an SEO, uptime or analytics service (Tier 4)
To give Lighthouse Audit the same answer as its siblings, stack User-agent: Chrome-Lighthouse with their lines above one set of rules; to treat Lighthouse Audit differently, give it its own group.
Other SEO tools that do the same job (checks pages for an SEO, uptime or analytics service) include AhrefsBot from Ahrefs, AhrefsSiteAudit from Ahrefs, AwarioBot from Awario, AwarioRssBot from Awario, AwarioSmartBot from Awario, DataForSeoBot from DataForSEO. Deciding about Lighthouse Audit is usually a decision about the whole group, so check how your file treats these too.
We first recorded Chrome-Lighthouse on March 17, 2026. We could not find a page where Google names it, so treat the token as reported rather than documented.
Which rule Lighthouse Audit actually follows
Lighthouse Audit reads exactly one group in robots.txt, the most specific one that names Chrome-Lighthouse, and never combines rules across groups. This short file shows the trap:
User-agent: *
Disallow: /private/
User-agent: Chrome-Lighthouse
Disallow: /drafts/- Find the group. Lighthouse Audit looks for a group naming
Chrome-Lighthouse. One exists, so it ignoresUser-agent: *completely. - Apply only that group. It is refused
/drafts/and nothing else. - The surprise.
/private/is open to Lighthouse Audit, because that rule lives in the*group it no longer reads. To keep it out of both, repeatDisallow: /private/inside its own group.
Test yourself: does a rule under User-agent: * apply to Lighthouse Audit if the file also has a User-agent: Chrome-Lighthouse group?
No. Once a group names it, Lighthouse Audit reads only that group. Put every rule you want it to follow inside its own group.
Test yourself: will blocking Lighthouse Audit remove your pages from AI answers?
Often, yes. Lighthouse Audit is a utility crawler, so pages it cannot fetch can drop out of the answers or results it supports.
Related: how AI engines choose their sources
Test yourself: is User-agent: chrome-lighthouse the same as User-agent: Chrome-Lighthouse?
Yes. RFC 9309 makes user-agent matching case-insensitive. Paths are a different story: Disallow: /Blog/ does not block /blog/.
Should you allow Lighthouse Audit? Decide by situation
| If you are... | Recommended setting |
|---|---|
| You publish content and want AI answers to cite it | Low stakes either way. It does not decide whether AI answers cite you. |
| You license content and want to stop AI training | Blocking it does not stop training, because Lighthouse Audit is a utility crawler. Block the operator's training crawler instead. |
| You run an online shop | Allow it unless your logs show it is costly. |
| Your server is under load from bots | Rate-limit before blocking. It is rated safe in our database. |
Check Lighthouse Audit on your own site
- Open
/robots.txton your domain and search forChrome-Lighthouse. If it is not named, it followsUser-agent: *. - List the
Disallowlines in the group Lighthouse Audit follows and test your key URLs against them; the longest match wins, andAllowwins a tie. - Look beyond the file. A firewall or bot manager can refuse Lighthouse Audit even when robots.txt allows it, and that never shows in the file.
- Run our blocked AI crawler check to see how Lighthouse Audit and every other crawler we track are treated in one pass, including firewall refusals.
Common mistakes with Lighthouse Audit
The errors we see most often with Lighthouse Audit in the files and firewalls we test:
- Treating Lighthouse Audit as an AI or search crawler. Blocking it has little effect on visibility; decide based on load and what it does with your data.
- Relying on robots.txt alone when Lighthouse Audit is rated caution or aggressive. Back the rule with a server-side block.
- Blocking Lighthouse Audit by IP alone. Ranges change; match the token and verify with logs.
All three hide inside a file that looks correct, so check Lighthouse Audit from outside after every change.
Spotting Lighthouse Audit in your logs
robots.txt says what Lighthouse Audit may do; your access logs show what it actually did.
Count requests
On a server with standard Nginx or Apache logs, this counts matching requests per day (adjust the log path for your host):
grep -iE "Chrome-Lighthouse" /var/log/nginx/access.log \
| awk '{print $4}' | cut -d: -f1 | sort | uniq -cAnd this shows which paths it requested most, which is the quickest way to see whether your Disallow lines are being respected:
grep -iE "Chrome-Lighthouse" /var/log/nginx/access.log \
| awk '{print $7}' | sort | uniq -c | sort -rn | head -20Check the requests are genuine
Anyone can send the Lighthouse Audit user-agent, so confirm the source before acting on a match:
Chrome-Lighthouse: we hold no published IP list, so use reverse DNS where the operator documents a hostname and treat an unverifiable Lighthouse Audit request with caution.
Frequently Asked Questions
What user-agent string does Lighthouse Audit use?
Chrome-Lighthouse. Evidence that the spelling is in real use comes from GitHub (GoogleChrome/lighthouse source), not from Google, which has not published crawler documentation naming it. Use it in robots.txt as the best available match, and treat a request carrying it as a clue rather than proof of who sent it.Is Lighthouse Audit safe?
Will blocking Lighthouse Audit hurt my SEO?
How do I block Lighthouse Audit in robots.txt?
/robots.txt file:User-agent: Chrome-Lighthouse Disallow: /
This instructs Lighthouse Audit not to crawl any path on your site. To block only specific sections, replace / with the path (e.g.,
Disallow: /blog/).Does Lighthouse Audit respect robots.txt?
Chrome-Lighthouse will stop a client that chooses to honour it; for enforcement, add a firewall or CDN rule as well.How do I verify if Lighthouse Audit is crawling my site?
Chrome-Lighthouse (for example grep -i "Chrome-Lighthouse" /var/log/nginx/access.log). Because the operator publishes no IP ranges or reverse-DNS pattern, a match shows that something used the name, not that Google sent it.