B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Current
21%
21% -- share of top 1000 websites with gptbot rules for Top 1,000 websites (2026)
An HTTP Archive analysis by Paul Calvano found that almost 21% of the top 1,000 websites include robots.txt rules for GPTBot.
- Heavily over-represents publishers with licensing deals and legal teams compared to broader business websites.
Attribution:
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Lighthouse Research Team
Last verified:
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Source verified
Evidence graded
Value
21%
Unit
Percentage
Data Vintage
2026
Entity
Sample Size
1,000
Evidence Quality
B
Strong, reliable evidence
Sourced from a well-regarded research firm or industry leader with transparent methodology and a reasonably large sample.
Single source - not yet corroborated
Score breakdown
Extraction
75
Source Trust
60
Citation Chain
20
Independence
30
Methodology
45
Freshness
95
Source
Paul Calvano / HTTP Archive
Primary
Tier B
https://www.ai-visibility.org.uk/blog/is-your-website-blocking-ai/ ↗
Source Article
Is Your Website Blocking AI Crawlers? How to Check | AI Visibility
Why your website might be invisible to AI crawlers
Your website might be invisible to AI, and you'd never know it.
When someone asks ChatGPT, Claude, or Gemini about your industry, your competitors show up. You don't. Not because your content is weak or your site is new, but because something techni…
Original Research
Paul Calvano / HTTP Archive
· Original study ↗
Methodology
HTTP Archive analysis by Paul Calvano, as cited
Methodology documented
Segmentation
Industrymarketing
Cite this stat
Plain Text
Top 1,000 websites: 21% share of top 1000 websites with gptbot rules. Source: Paul Calvano / HTTP Archive (2026). Via Lighthouse Intelligence -- https://lighthousedata.io/data/top1000-sites-gptbot-rules-calvano
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<blockquote cite="https://lighthousedata.io/data/top1000-sites-gptbot-rules-calvano" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>21%</strong> -- share of top 1000 websites with gptbot rules for Top 1,000 websites<br><small>Source: Paul Calvano / HTTP Archive (2026) · <a href="https://lighthousedata.io/data/top1000-sites-gptbot-rules-calvano" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
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