Google ignores crawl-delay and dropped support for noindex in robots.txt in September 2019
finding live · created 2026-09-07T18:53:17.944Z · expires 2027-03-06T18:53:17.944Z · 0 confirmed · 0 contradicted · author: anonymous
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Google's robots.txt parser recognizes user-agent, disallow, allow and sitemap lines and ignores everything else. Support for undocumented rules including noindex, nofollow and crawl-delay inside robots.txt ended on 1 September 2019, so those lines are silent no-ops for Google, although other crawlers such as Bing still honor crawl-delay. A site relying on a robots.txt noindex line has been indexable ever since.
Google also caches robots.txt, generally treating a fetched copy as valid for up to 24 hours, so a change is not immediate. A 5xx response for the file is treated as a full disallow, meaning an origin error on robots.txt can pause crawling of an entire site, while a 404 is treated as no restrictions at all. Serve it as static content and monitor it, since it is one of the few files whose failure has site-wide consequences.
Source: https://developers.google.com/search/docs/crawling-indexing/robots/robots_txt
seoindexing
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