Chrome-Lighthouse (Google): User Agent & robots.txt Rules

Q: What is the official user-agent string for Chrome-Lighthouse?

The official user-agent string for Chrome-Lighthouse is: Chrome-Lighthouse. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from Chrome-Lighthouse by performing a reverse-DNS lookup on the source IP - legitimate bots resolve back to their operator's domain.

Q: How do I block Chrome-Lighthouse in robots.txt?

Add the following lines to your /robots.txt file: User-agent: Chrome-Lighthouse Disallow: / This instructs Chrome-Lighthouse not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g., Disallow: /blog/). Note: robots.txt is publicly readable - any bot or human can inspect it at yourdomain.com/robots.txt.

Q: How do I verify if Chrome-Lighthouse is crawling my site?

Search your web server access logs for the string Chrome-Lighthouse (case-insensitive grep: grep -i "Chrome-Lighthouse" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For Chrome-Lighthouse specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).

Quick Facts

User-Agent:: Chrome-Lighthouse
Category:: SEO Tools
Operator:: Google
Safety:: Safe
Blocking Impact:: Varies - Evaluate before blocking
SEO Impact Score:: 0/10
Official docs:: developers.google.com

What is Chrome-Lighthouse?

Chrome-Lighthouse is the crawler used by Google PageSpeed Insights to audit web pages for performance, accessibility, and SEO.

Chrome-Lighthouse is the crawler used by Google PageSpeed Insights to audit web pages for performance, accessibility, and SEO. Chrome-Lighthouse is a commercial SEO analytics crawler operated by Google. It builds backlink graphs, crawls for technical SEO issues, and tracks keyword rankings. The user-agent Chrome-Lighthouse is well-known and respected in the SEO industry. Blocking it removes your domain from Google's index, preventing competitors from analysing your backlink profile via their platform. However, other Google users also lose visibility into links pointing TO your site - weigh this trade-off carefully.

What happens if you block Chrome-Lighthouse?

❓ **Impact Unknown** - The SEO consequences of blocking Chrome-Lighthouse are not fully documented. Before blocking, check your analytics to confirm whether this bot generates referral traffic, review your server logs for crawl frequency, and test in a staging environment if possible.

Generally safe to allow; provides legitimate crawling value.

How to block Chrome-Lighthouse with robots.txt

<code>User-agent: Chrome-Lighthouse</code> - Matching is case-insensitive. Robots.txt is fetched from the root of each subdomain separately.

Block completely (robots.txt)

User-agent: Chrome-Lighthouse
Disallow: /

Allow all (robots.txt)

User-agent: Chrome-Lighthouse
Allow: /

Block private only (robots.txt)

User-agent: Chrome-Lighthouse
Disallow: /private/
Disallow: /api/
Disallow: /admin/
Allow: /

Nginx server block

# Nginx: Hard-block Chrome-Lighthouse
if ($http_user_agent ~* "Chrome\-Lighthouse") {
    return 403 "Bot blocked";
}

Apache .htaccess

# Apache: Hard-block Chrome-Lighthouse
SetEnvIfNoCase User-Agent "Chrome\-Lighthouse" bad_bot
Order Allow,Deny
Allow from all
Deny from env=bad_bot

Meta robots tag

X-Robots-Tag header

X-Robots-Tag: noindex, nofollow

Is Chrome-Lighthouse safe to allow?

Yes, Chrome-Lighthouse is a **safe and legitimate** crawler. It is operated by Google, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string Chrome-Lighthouse is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).

Verify by reverse-DNS lookup: legitimate Chrome-Lighthouse requests resolve to google's domain.

What does Chrome-Lighthouse do?

Understanding Chrome-Lighthouse's purpose helps you decide whether to allow or block it.

Analyzes website structure and SEO health
Tracks backlinks and referring domains
Monitors keyword rankings and competitor analysis
Crawls sites for technical SEO audits
Generates reports for SEO professionals

Frequently Asked Questions

What is the official user-agent string for Chrome-Lighthouse?

The official user-agent string for Chrome-Lighthouse is: Chrome-Lighthouse. This is the exact string you must use in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. User-agent matching in robots.txt is case-insensitive, but the string must be spelled correctly. You can verify that a request genuinely comes from Chrome-Lighthouse by performing a reverse-DNS lookup on the source IP - legitimate bots resolve back to their operator's domain.

Is Chrome-Lighthouse safe?

Yes, Chrome-Lighthouse is a **safe and legitimate** crawler. It is operated by Google, which publicly documents its crawler at an official URL and follows the Robots Exclusion Protocol (RFC 9309). The user-agent string Chrome-Lighthouse is verifiable via reverse-DNS lookup on the crawling IP addresses. You can safely allow it unless you have a specific reason to block (e.g., AI training opt-out or SEO tool visibility).

Will blocking Chrome-Lighthouse hurt my SEO?

❓ **Impact Unknown** - The SEO consequences of blocking Chrome-Lighthouse are not fully documented. Before blocking, check your analytics to confirm whether this bot generates referral traffic, review your server logs for crawl frequency, and test in a staging environment if possible.

How do I block Chrome-Lighthouse in robots.txt?

Add the following lines to your /robots.txt file:

User-agent: Chrome-Lighthouse
Disallow: /

This instructs Chrome-Lighthouse not to crawl any path on your site. The Disallow: / directive covers the entire domain including subfolders. To only block specific sections, replace / with the path (e.g., Disallow: /blog/). Note: robots.txt is publicly readable - any bot or human can inspect it at yourdomain.com/robots.txt.

Does Chrome-Lighthouse respect robots.txt?

Yes - Chrome-Lighthouse is a well-behaved bot operated by Google. It fetches and parses /robots.txt before crawling any page, following RFC 9309.

How do I verify if Chrome-Lighthouse is crawling my site?

Search your web server access logs for the string Chrome-Lighthouse (case-insensitive grep: grep -i "Chrome-Lighthouse" /var/log/nginx/access.log). You can also check Google Search Console → Coverage → Crawl Stats for Googlebot variants. For Chrome-Lighthouse specifically, filter by user-agent in your log analysis tool (GoAccess, AWStats, etc.).

What is the crawl frequency of Chrome-Lighthouse?

Chrome-Lighthouse crawls at a moderate rate. If you notice excessive traffic in your logs, you can add a Crawl-delay directive:

User-agent: Chrome-Lighthouse
Crawl-delay: 10

(10 second delay between requests).

Can I block Chrome-Lighthouse from specific pages only?

Yes. Instead of a global Disallow: / you can restrict Chrome-Lighthouse to specific paths:

User-agent: Chrome-Lighthouse
Disallow: /private/
Disallow: /staging/
Allow: /

This allows Chrome-Lighthouse everywhere except the listed paths. Path matching in robots.txt uses prefix matching - Disallow: /private/ blocks /private/page.html but NOT /public/private/.

Why would I want to block Chrome-Lighthouse?

There are two main reasons to block Chrome-Lighthouse: 1. **Competitive intelligence**: Google users (your competitors) can analyse your backlink profile, keyword rankings, and site structure. Blocking prevents this. 2. **Crawl budget**: If your site is large, SEO tool crawlers consume crawl bandwidth without contributing to search rankings. Blocking frees up server resources for search engine bots. The trade-off: you also become invisible in Google's backlink database, meaning links pointing TO your site from other domains won't appear in competitor reports either.