Who blocks AI · #352 in the Majestic Million
Does biomedcentral.com block AI crawlers?
No. biomedcentral.com has no robots.txt, so every crawler may crawl it, AI crawlers included.
GPTBotAllowedOAI-SearchBotAllowedClaudeBotAllowedPerplexityBotAllowedGoogle-ExtendedAllowedCCBotAllowed- robots.txt
- www.biomedcentral.com/robots.txt · answers 404: no robots.txt
- llms.txt
- none
- Checked
- 9 November 2026, as canaicrawl. We check again every week.
Every bot, and the line that decides
Search engines
| Bot | Operator | robots.txt | Deciding line |
|---|---|---|---|
Googlebot | Allowed | no robots.txt | |
Bingbot | Microsoft | Allowed | no robots.txt |
DuckDuckBot | DuckDuckGo | Allowed | no robots.txt |
Applebot | Apple | Allowed | no robots.txt |
PetalBot | Huawei | Allowed | no robots.txt |
YandexBot | Yandex | Allowed | no robots.txt |
Baiduspider | Baidu | Allowed | no robots.txt |
AI search
| Bot | Operator | robots.txt | Deciding line |
|---|---|---|---|
OAI-SearchBot | OpenAI | Allowed | no robots.txt |
PerplexityBot | Perplexity | Allowed | no robots.txt |
Claude-SearchBot | Anthropic | Allowed | no robots.txt |
DuckAssistBot | DuckDuckGo | Allowed | no robots.txt |
Amazonbot | Amazon | Allowed | no robots.txt |
YouBot | You.com | Allowed | no robots.txt |
AI training
| Bot | Operator | robots.txt | Deciding line |
|---|---|---|---|
GPTBot | OpenAI | Allowed | no robots.txt |
ClaudeBot | Anthropic | Allowed | no robots.txt |
Google-Extended | Allowed | no robots.txt | |
CCBot | Common Crawl | Allowed | no robots.txt |
Applebot-Extended | Apple | Allowed | no robots.txt |
GoogleOther | Allowed | no robots.txt | |
Meta-ExternalAgent | Meta | Allowed | no robots.txt |
Bytespider | ByteDance | Allowed | no robots.txt |
User-triggered fetchers
| Bot | Operator | robots.txt | Deciding line |
|---|---|---|---|
ChatGPT-User | OpenAI | Allowed | no robots.txt |
Claude-User | Anthropic | Allowed | no robots.txt |
Perplexity-User | Perplexity | Allowed | no robots.txt |
MistralAI-User | Mistral | Allowed | no robots.txt |
Meta-ExternalFetcher | Meta | Allowed | no robots.txt |
SEO tools
| Bot | Operator | robots.txt | Deciding line |
|---|---|---|---|
AhrefsBot | Ahrefs | Allowed | no robots.txt |
SemrushBot | Semrush | Allowed | no robots.txt |
MJ12bot | Majestic | Allowed | no robots.txt |
DotBot | Moz | Allowed | no robots.txt |
What do the bots actually get?
This page reads robots.txt, which states what biomedcentral.com asks of crawlers. A firewall or CDN can still refuse a bot that robots.txt allows. The live check requests the page as each bot and shows the status it gets.
Run a live check on biomedcentral.com Test a path in the robots.txt tester
History
- 19 October 2026: first checked.
Questions
Does biomedcentral.com block GPTBot?
No. biomedcentral.com has no robots.txt, so nothing stops GPTBot. GPTBot is OpenAI’s crawler for training data; blocking it doesn’t affect ChatGPT search, which uses OAI-SearchBot. Checked 9 November 2026.
Does biomedcentral.com block ClaudeBot?
No. biomedcentral.com has no robots.txt, so nothing stops ClaudeBot. ClaudeBot is Anthropic’s crawler for training data. Checked 9 November 2026.
Does biomedcentral.com block Google-Extended?
No. biomedcentral.com has no robots.txt, so nothing stops Google-Extended. Google-Extended is the token that controls whether Google may use pages for Gemini training and grounding; it doesn’t affect Google Search. Checked 9 November 2026.
Does biomedcentral.com block PerplexityBot?
No. biomedcentral.com has no robots.txt, so nothing stops PerplexityBot. PerplexityBot is the crawler that indexes pages for Perplexity’s answers. Checked 9 November 2026.
Can ChatGPT search find biomedcentral.com?
Yes. biomedcentral.com has no robots.txt, so nothing stops OAI-SearchBot. OAI-SearchBot is the crawler behind ChatGPT search; blocking it keeps the site out of ChatGPT’s search answers. Checked 9 November 2026.