List Of All The GoogleBot Robots.txt Specifications Changes

Jul 2, 2019 - 8:01 am 2 by

Google Gate

With Google aiming to make the robots.txt exclusion protocol a standard, they proposed some changes and submitted them the other day. Now, Google updated their own developer docs around the robots.txt specification to match. Here is a list of what has changed.

  • Removed the "Requirements Language" section in this document because the language is Internet draft specific.
  • Robots.txt now accepts all URI-based protocols.
  • Google follows at least five redirect hops. Since there were no rules fetched yet, the redirects are followed for at least five hops and if no robots.txt is found, Google treats it as a 404 for the robots.txt. Handling of logical redirects for the robots.txt file based on HTML content that returns 2xx (frames, JavaScript, or meta refresh-type redirects) is discouraged and the content of the first page is used for finding applicable rules.
  • For 5xx, if the robots.txt is unreachable for more than 30 days, the last cached copy of the robots.txt is used, or if unavailable, Google assumes that there are no crawl restrictions.
  • Google treats unsuccessful requests or incomplete data as a server error.
  • "Records" are now called "lines" or "rules", as appropriate.
  • Google doesn't support the handling of elements with simple errors or typos (for example, "useragent" instead of "user-agent").
  • Google currently enforces a size limit of 500 kibibytes (KiB), and ignores content after that limit.
  • Updated formal syntax to be valid Augmented Backus-Naur Form (ABNF) per RFC5234 and to cover for UTF-8 characters in the robots.txt.
  • Updated the definition of "groups" to make it shorter and more to the point. Added an example for an empty group.
  • Removed references to the deprecated Ajax Crawling Scheme.

The big changes are (1) GoogleBot will follows 5 redirect hops (which we knew in 2014), (2) there are no crawl restrictions if unavailable is greater than 30 days, (3) unsuccessful requests=server error, (4) there is a 500 KiB size limit and (5) it supports URI-based protocols.

Here are some additional answers:

Forum discussion at Twitter.


Popular Categories

The Pulse of the search community


Search Video Recaps

Google Weekend Volatility, Google On Search Leak, Elizabeth Tucker Interview & Apple Intelligence - YouTube
Video Details More Videos Subscribe to Videos

Most Recent Articles

Google Updates

Google Father's Day Weekend Search Ranking Volatility

Jun 16, 2024 - 8:32 am
Search Forum Recap

Daily Search Forum Recap: June 14, 2024

Jun 14, 2024 - 10:00 am
Search Video Recaps

Search News Buzz Video Recap: Google Weekend Volatility, Google On Search Leak, Elizabeth Tucker Interview, Apple Intelligence & More

Jun 14, 2024 - 8:01 am

Google Tests Multiple Featured Snippets Under From Sources Across The Web

Jun 14, 2024 - 7:51 am
Google Search Engine Optimization

Google: Sometimes Search Experiments Conflict Causing Issues

Jun 14, 2024 - 7:41 am
Google Maps

Google Business Profiles Websites No Longer Load - 404

Jun 14, 2024 - 7:31 am
Previous Story: Google Shares Its Robots.txt Parser Code With Open Source World