Safe Official docs Search Engines

Baidu Union

Operated by Baidu

Quick Facts

User-Agent:
Baiduspider-cpro
Category:
Search Engines
Operator:
Baidu
Safety:
Safe
Blocking Impact:
Low - No SEO ranking impact
SEO Impact Score:
2/10
Official docs:
help.baidu.com

Confirmed by the operator

Baidu names Baiduspider-cpro on its own documentation page, linked above. The token, purpose and robots.txt behaviour on this profile come from that page, re-checked on October 19, 2026.

What is Baidu Union?

Baidu Union is a monitoring and validation agent operated by Baidu. It checks pages, ad destinations, or policy compliance rather than collecting training data. It has no effect on search rankings.

Baidu Union is a monitoring and validation agent operated by Baidu. It checks pages, ad destinations, or policy compliance rather than collecting training data. It has no effect on search rankings.
Baidu Union uses the user-agent token Baiduspider-cpro. 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 Baidu Union?

🔶 AI Visibility Trade-off - Blocking Baidu Union will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.
Generally safe to allow; provides legitimate crawling value.

How to block Baidu Union with robots.txt

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

Block completely (robots.txt)
User-agent: Baiduspider-cpro Disallow: /
Allow all (robots.txt)
User-agent: Baiduspider-cpro Allow: /
Block private only (robots.txt)
User-agent: Baiduspider-cpro Disallow: /private/ Disallow: /api/ Disallow: /admin/ Allow: /
Nginx server block
# Nginx: Hard-block Baidu Union if ($http_user_agent ~* "Baiduspider-cpro") { return 403 "Bot blocked"; }
Apache .htaccess
# Apache: Hard-block Baidu Union SetEnvIfNoCase User-Agent "Baiduspider-cpro" bad_bot Order Allow,Deny Allow from all Deny from env=bad_bot
Meta robots tag
<meta name="robots" content="noindex, nofollow">
X-Robots-Tag header
X-Robots-Tag: noindex, nofollow

Is Baidu Union safe to allow?

Yes, Baidu Union is a safe and legitimate crawler operated by Baidu. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.
Verify by reverse-DNS lookup: legitimate Baidu Union requests resolve to Baidu's domain.

What does Baidu Union do?

Understanding Baidu Union'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

Baidu Union in context

Baidu Union is a utility crawler operated by Baidu. In plain terms, it checks pages for an SEO, uptime or analytics service. Our database files it under search engines and ranks it Tier 3, mid-priority crawlers with a clear purpose but a smaller audience. 62 of the 63 search engines in our database share this tier.

Its safety rating is safe and its blocking impact is not documented. So the decision about Baidu Union rests on what you want from Baidu, not on its behaviour. How we rate safety and impact.

How site owners treat Baidu Union

Our robots.txt study of the Tranco top 10,000 did not track Baiduspider-cpro as a named token, so we do not publish an adoption figure for it. If you run a large site, your own logs are the best evidence of how often it visits.

Does it follow robots.txt?

Baidu Union's operator does not clearly document how it treats robots.txt. Write the Baidu Union rule anyway, then confirm in your logs that its requests stop.

Baidu crawlers and close alternatives

Baidu Union is one of 10 Baidu crawlers in our database. A User-agent: Baiduspider-cpro group controls Baidu Union only; the other Baidu tokens below need their own lines.

  • Baiduspider-cpro: this crawler (Tier 3)
  • baidu: baidu, builds a search or answer index (Tier 3)
  • Baiduspider: Baidu Search, builds a search or answer index (Tier 3)
  • Baiduspider-ads: Baidu Business Search, checks pages for an SEO, uptime or analytics service (Tier 3)
  • Baiduspider-favo: Baidu Bookmark, builds a search or answer index (Tier 3)
  • Baiduspider-image: Baidu Image Search, builds a search or answer index (Tier 3)
  • Baiduspider-news: Baidu News Search, builds a search or answer index (Tier 3)
  • Baiduspider-video: Baidu Video Search, builds a search or answer index (Tier 3)
  • ERNIEBot: ERNIE (Baidu), collects pages to train AI models (Tier 2)

To give Baidu Union the same answer as its siblings, stack User-agent: Baiduspider-cpro with their lines above one set of rules; to treat Baidu Union differently, give it its own group.

Other search engines that do the same job (checks pages for an SEO, uptime or analytics service) include AdIdxBot from Microsoft, YaDirectFetcher from Yandex, YandexAdNet from Yandex, YandexCheckBot from Yandex, YandexDirect from Yandex, YandexDirectDyn from Yandex. Deciding about Baidu Union is usually a decision about the whole group, so check how your file treats these too.

We first recorded Baiduspider-cpro on September 22, 2026. Baidu documents it on help.baidu.com, and we recheck that page before each release.

Which rule Baidu Union actually follows

Baidu Union reads exactly one group in robots.txt, the most specific one that names Baiduspider-cpro, and never combines rules across groups. This short file shows the trap:

User-agent: *
Disallow: /private/

User-agent: Baiduspider-cpro
Disallow: /drafts/
  1. Find the group. Baidu Union looks for a group naming Baiduspider-cpro. One exists, so it ignores User-agent: * completely.
  2. Apply only that group. It is refused /drafts/ and nothing else.
  3. The surprise. /private/ is open to Baidu Union, because that rule lives in the * group it no longer reads. To keep it out of both, repeat Disallow: /private/ inside its own group.
Test yourself: does a rule under User-agent: * apply to Baidu Union if the file also has a User-agent: Baiduspider-cpro group?

No. Once a group names it, Baidu Union reads only that group. Put every rule you want it to follow inside its own group.

Test yourself: will blocking Baidu Union remove your pages from AI answers?

Often, yes. Baidu Union is a utility crawler, so pages it cannot fetch can drop out of the answers or results it supports.

Test yourself: is User-agent: baiduspider-cpro the same as User-agent: Baiduspider-cpro?

Yes. RFC 9309 makes user-agent matching case-insensitive. Paths are a different story: Disallow: /Blog/ does not block /blog/.

Should you allow Baidu Union? Decide by situation

Recommended setting for Baidu Union by type of site
If you are...Recommended setting
You publish content and want AI answers to cite itLow stakes either way. It does not decide whether AI answers cite you.
You license content and want to stop AI trainingBlocking it does not stop training, because Baidu Union is a utility crawler. Block the operator's training crawler instead.
You run an online shopAllow it unless it is overloading your servers.
Your server is under load from botsRate-limit before blocking. It is rated safe in our database.

Check Baidu Union on your own site

  1. Open /robots.txt on your domain and search for Baiduspider-cpro. If it is not named, it follows User-agent: *.
  2. List the Disallow lines in the group Baidu Union follows and test your key URLs against them; the longest match wins, and Allow wins a tie.
  3. Look beyond the file. A firewall or bot manager can refuse Baidu Union even when robots.txt allows it, and that never shows in the file.
  4. Run our LLM crawler checker to see how Baidu Union and every other crawler we track are treated in one pass, including firewall refusals.

Common mistakes with Baidu Union

The errors we see most often with Baidu Union in the files and firewalls we test:

  1. Treating Baidu Union as an AI or search crawler. Blocking it has little effect on visibility; decide based on load and what it does with your data.
  2. Relying on robots.txt alone when Baidu Union is rated caution or aggressive. Back the rule with a server-side block.
  3. Blocking Baidu Union by IP alone. Ranges change; match the token and verify with logs.

All three hide inside a file that looks correct, so check Baidu Union from outside after every change.

Spotting Baidu Union in your logs

robots.txt says what Baidu Union 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 "Baiduspider-cpro" /var/log/nginx/access.log \
  | awk '{print $4}' | cut -d: -f1 | sort | uniq -c

And this shows which paths it requested most, which is the quickest way to see whether your Disallow lines are being respected:

grep -iE "Baiduspider-cpro" /var/log/nginx/access.log \
  | awk '{print $7}' | sort | uniq -c | sort -rn | head -20

Check the requests are genuine

Anyone can send the Baidu Union user-agent, so confirm the source before acting on a match:

  • Baiduspider-cpro: we hold no published IP list, so use reverse DNS where the operator documents a hostname and treat an unverifiable Baidu Union request with caution.

Frequently Asked Questions

What is the official user-agent string for Baidu Union?
The official user-agent string for Baidu Union is: Baiduspider-cpro. Use this exact string in robots.txt, Nginx, Apache, or Cloudflare firewall rules to target this bot. Matching in robots.txt is case-insensitive. Verify a request genuinely comes from Baidu Union by performing a reverse-DNS lookup on the source IP.
Is Baidu Union safe?
Yes, Baidu Union is a safe and legitimate crawler operated by Baidu. It follows the Robots Exclusion Protocol (RFC 9309) and can be controlled with standard robots.txt rules.
Will blocking Baidu Union hurt my SEO?
🔶 AI Visibility Trade-off - Blocking Baidu Union will not hurt Google or Bing rankings, but it can remove your content from AI search answers and assistant citations powered by this crawler. Block only if you have a deliberate reason.
How do I block Baidu Union in robots.txt?
Add the following lines to your /robots.txt file:
User-agent: Baiduspider-cpro
Disallow: /

This instructs Baidu Union not to crawl any path on your site. To block only specific sections, replace / with the path (e.g., Disallow: /blog/).
Does Baidu Union respect robots.txt?
Baidu Union is operated by Baidu and is expected to fetch and parse /robots.txt before crawling, following RFC 9309. For hard enforcement, combine robots.txt with server-level IP or user-agent blocking.
How do I verify if Baidu Union is crawling my site?
Search your web server access logs for the string Baiduspider-cpro (case-insensitive: grep -i "Baiduspider-cpro" /var/log/nginx/access.log). Filter by user-agent in your log analytics tool (GoAccess, AWStats, etc.).

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