List of Google's special-case crawlers
The special-case crawlers are used by specific Google products where there's an agreement between
  the crawled site and the product about the crawl process. For example, AdsBot 
ignores
  the global robots.txt user agent ( * 
) with the ad publisher's permission. The general technical properties 
of Google's crawlers also apply to the special-case crawlers.
The
  special-case crawlers may ignore robots.txt rules and so they operate from a different IP range
  than the common crawlers. The IP ranges are published in the special-crawlers.json 
object. The
  special-case crawlers' reverse DNS mask matches rate-limited-proxy-***-***-***-***.google.com 
.
The following list shows the special-case crawlers, their user agent strings as they appear in
  the HTTP requests, their user agent tokens for the User-agent: 
line in robots.txt,
  and the products that are affected by crawl preferences for the crawler. The list is not
  exhaustive, it only covers the requestors that are more likely to show up in log files and that
  we've received questions about.
-  APIs-Google
-  User-Agent in HTTP requestsAPIs-Google (+https://developers.google.com/webmasters/APIs-Google.html) robots.txtUser-agent token in robots.txt APIs-Google
 The global user agent ( *) is ignored.Example robots.txt group user-agent: APIs-Googleallow: /archive/1Q84 disallow: /archive/ Affected productsCrawling preferences addressed to theAPIs-Googleuser agent affect the delivery of push notification messages by Google APIs.
-  AdsBot Mobile Web
-  User-Agent in HTTP requestsMozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ W.X.Y.Z Mobile Safari/537.36 (compatible; AdsBot-Google-Mobile; +http://www.google.com/mobile/adsbot.html) robots.txtUser-agent token in robots.txt AdsBot-Google-Mobile
 The global user agent ( *) is ignored.Example robots.txt group user-agent: AdsBot-Google-Mobileallow: /archive/1Q84 disallow: /archive/ Affected productsCrawling preferences addressed to theAdsBot-Google-Mobileuser agent affect Google Ads' ability to check web page ad quality .
-  AdsBot
-  User-Agent in HTTP requestsAdsBot-Google (+http://www.google.com/adsbot.html) robots.txtUser-agent token in robots.txt AdsBot-Google
 The global user agent ( *) is ignored.Example robots.txt group user-agent: AdsBot-Googleallow: /archive/1Q84 disallow: /archive/ Affected productsCrawling preferences addressed to theAdsBot-Googleuser agent affect Google Ads' ability to check web page ad quality .
-  AdSense
-  User-Agent in HTTP requestsDesktop agent Mediapartners-Google Mobile agent (Various mobile device types) (compatible; Mediapartners-Google/2.1; +http://www.google.com/bot.html)robots.txtUser-agent token in robots.txt Mediapartners-Google
 The global user agent ( *) is ignored.Example robots.txt group user-agent: Mediapartners-Googleallow: /archive/1Q84 disallow: /archive/ Affected productsCrawling preferences addressed to theMediapartners-Googleuser agent affect Google AdSense. The AdSense crawler visits participating sites in order to provide them with relevant ads.
-  Google-Safety
-  User-Agent in HTTP requests Google-Safety robots.txt The Google-Safety user agent ignores robots.txt rules. Affected products The Google-Safety user agent handles abuse-specific crawling, such as malware discovery for publicly posted links on Google properties. As such it's unaffected by crawling preferences. 
Retired special-case crawlers
The following special-case crawlers are no longer in use, and are only noted here for historical reference.
-  AdsBot Mobile Web
-  User-Agent in HTTP requestsMozilla/5.0 (iPhone; CPU iPhone OS 14_7_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.2 Mobile/15E148 Safari/604.1 (compatible; AdsBot-Google-Mobile; +http://www.google.com/mobile/adsbot.html) robots.txtUser-agent token in robots.txtAdsBot-Google-Mobile
 The global user agent ( *) is ignored.Affected productsCrawling preferences addressed to theAdsBot-Google-Mobileuser agent affected Google Ads' ability to check iPhone web page ad quality .
-  Duplex on the web
-  User-Agent in HTTP requestsMozilla/5.0 (Linux; Android 11; Pixel 2; DuplexWeb-Google/1.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.193 Mobile Safari/537.36 robots.txtUser-agent token in robots.txtDuplexWeb-Google
 Duplex on the web may ignore the *wildcard.Affected productsSupported the Duplex on the web service.
-  Google Favicon
-  User-Agent in HTTP requestsMozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.75 Safari/537.36 Google Favicon robots.txtUser-agent token in robots.txtGooglebot-Image
 Googlebot
-  Mobile Apps Android
-  User-Agent in HTTP requestsAdsBot-Google-Mobile-Apps robots.txtUser-agent token in robots.txtAdsBot-Google-Mobile-Apps
 The AdsBot-Google-Mobile-Appsuser agent obeyedAdsBot-Googlerobots rules, but ignored the global user agent (*).Affected productsCrawling preferences addressed to theAdsBot-Google-Mobile-Appsuser agent affect Google Ads' ability to check Android app page ad quality .
-  Web Light
-  User-Agent in HTTP requestsMozilla/5.0 (Linux; Android 4.2.1; en-us; Nexus 5 Build/JOP40D) AppleWebKit/535.19 (KHTML, like Gecko; googleweblight) Chrome/38.0.1025.166 Mobile Safari/535.19 robots.txtUser-agent token in robots.txtgoogleweblight
 The googleweblightuser agent was used only for explicit browse requests of a human visitor, and so it ignored robots.txt rules, which are used to block automated crawling requests.Affected productsThe Web Light user agent checked for the presence of theno-transformheader whenever a user clicked your page in Search under appropriate conditions.

