What is Observer?

Observer is a bot in the SEO crawlers category, operated by Obsrvr.

Bot name
Observer
Operator
Obsrvr
Category
SEO Crawlers
Type
Bot
Respects robots.txt
Yes
robots.txt user agent
Observer
Signs requests (Web Bot Auth)
No

About Observer

Crawler looking for broken links to help improve world wide web as a whole.

SEO crawlers map links, keywords and technical issues for SEO tools and backlink databases. They help the tool's customers, often your competitors, rather than you. Rate limit or block the ones you do not use.

Observer user agent

Observer identifies itself with this user agent string:

Anyone can copy a user agent string. Transfon Security also checks where each request comes from, so a request that claims to be a known crawler but comes from the wrong network is treated as a fake, not as the real crawler.

How to block Observer in robots.txt

Observer follows robots.txt, so these rules stop it crawling the paths you choose. robots.txt is a plain text file at the root of your domain, such as https://example.com/robots.txt.

Block Observer from the whole site

User-agent: Observer
Disallow: /

Block Observer from some folders

User-agent: Observer
Disallow: /private/
Disallow: /search

Allow Observer only on some folders

User-agent: Observer
Allow: /blog/
Disallow: /

Allow Observer and block other crawlers

User-agent: Observer
Allow: /

User-agent: *
Disallow: /

Things to know

  • Each host needs its own file. Rules on www.example.com do not apply to shop.example.com.
  • A crawler obeys only the most specific group that names it. Once you add a User-agent: Observer group, Observer ignores your User-agent: * rules, so repeat any that should still apply.
  • The user agent name is not case sensitive. We take Observer from Observer's user agent; check Obsrvr's own documentation if it publishes a different robots.txt name.
  • Crawlers cache robots.txt, so changes can take up to a day to apply. Disallow stops crawling but does not remove pages already collected or indexed.

Limits of robots.txt

  1. Observer may not follow the rule. Observer says it follows robots.txt, but nothing enforces that. Changes can take a day to apply, the operator can change its policy, and other crawlers from Obsrvr use different names and rules.
  2. The user agent could be fake. robots.txt matches the name a request claims. Anyone can send Observer's user agent, and a scraper using it is not bound by Obsrvr's robots.txt policy. Only checking the source network tells a real Observer from a fake one.

Treat robots.txt as a statement of your policy, and enforce it where requests arrive.

Who should care about Observer

Publishers

Observer works for an SEO tool's customers, often your competitors. It adds server load without readers, so rate limit or block it unless you use the tool.

Transfon Security for publishers

Media buyers and advertisers

SEO crawlers map landing pages and links for competitor research. Keep Observer's visits out of campaign data.

Transfon Security for advertisers

E-commerce

Observer can map your catalogue, prices and site structure for competitors. Block it unless you use the tool yourself.

Transfon Security for e-commerce

SaaS and APIs

Allow Observer only if your team uses the tool; otherwise rate limit it on docs and marketing pages.

Transfon Security for SaaS and APIs

Block Observer with Transfon Security

robots.txt is a request, not an enforcement. Transfon Security shows Observer by name in the Top Bots report, so you can see how often it visits and which pages it reads. Block or allow it with a User Agent rule, or slow it down with a rate limit decision rule.

Transfon Security

Control Observer on your site

  • See every Observer visit and the pages it reads
  • Spot bots that fake trusted crawler names
  • Block, allow or rate limit Observer with one rule
  • Works with or without robots.txt support

Frequently asked questions

What is Observer?

Observer is a bot in the SEO crawlers category, operated by Obsrvr. Crawler looking for broken links to help improve world wide web as a whole.

Does Observer respect robots.txt?

Yes. Observer follows robots.txt, so a Disallow rule for the Observer user agent stops it from crawling the paths you list.

How do I block Observer?

Add "User-agent: Observer" followed by "Disallow: /" to the robots.txt file at the root of your site. To enforce it, block requests whose user agent contains "obsrvr.net" at your WAF. In Transfon Security that is one User Agent block rule.

Is robots.txt enough to block Observer?

No. robots.txt is voluntary, so Observer may not follow it, and anyone can send Observer's user agent, so a fake Observer ignores your rule. Enforce the rule where requests arrive, at your WAF, and check the source network.

Should I block Observer?

SEO crawlers map links, keywords and technical issues for SEO tools and backlink databases. They help the tool's customers, often your competitors, rather than you. Rate limit or block the ones you do not use.

Related bots

All SEO crawlers · Full bot directory

See Which Bots Visit Your Site

Transfon Security identifies every bot in this directory in your traffic reports, flags fake search crawlers, and lets you allow, block or rate limit each bot.

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