robots.txt - Wikipedia

robots.txt - Wikipedia Jump to content Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Contribute Help Learn to edit Community portal Recent changes Upload file Special pages Search Search Appearance Donate Create account Log in Personal tools Donate Create account Log in Contents move to sidebar hide (Top) 1 History 2 Standard 3 Compliance Toggle Compliance subsection 3.1 Search engines 3.2 Archival sites 3.3 Artificial intelligence 4 Security 5 Alternatives 6 Examples Toggle Examples subsection 6.1 The use of the wildcard * in rules 7 Nonstandard extensions Toggle Nonstandard extensions subsection 7.1 Crawl-delay directive 7.2 Sitemap 7.3 Universal "*" match 7.4 Content-Signal 8 Meta tags and headers Toggle Meta tags and headers subsection 8.1 A "noindex" meta tag 8.2 A "noindex" HTTP response header 8.3 Maximum size of a robots.txt file 9 See also 10 References 11 Further reading 12 External links Toggle the table of contents robots.txt 28 languages العربية Azərbaycanca Boarisch Català Čeština Dansk Deutsch Español فارسی Suomi Français Galego עברית Bahasa Indonesia Italiano 日本語 한국어 Nederlands Polski Português Русский Simple English Српски / srpski Svenska ไทย Türkçe Українська 中文 Edit links Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Permanent link Page information Cite this page Get shortened URL Switch to legacy parser Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikidata item Appearance move to sidebar hide Checked From Wikipedia, the free encyclopedia Page version status This is an accepted version of this page This is the latest accepted revision, reviewed on 14 August 2026. File indicating parts for web crawling "},"native_name_lang":{"wt":""},"status":{"wt":"Proposed Standard"},"year_started":{"wt":""},"first_published":{"wt":"1994 published, formally standardized in 2022"},"version":{"wt":""},"version_date":{"wt":""},"preview":{"wt":""},"preview_date":{"wt":""},"organization":{"wt":""},"committee":{"wt":""},"series":{"wt":""},"editors":{"wt":""},"authors":{"wt":"{{plain list|\n* Martijn Koster (original author)\n* Gary Illyes, Henner Zeller, Lizzi Sassman (IETF contributors)\n}}"},"base_standards":{"wt":""},"related_standards":{"wt":""},"predecessor":{"wt":""},"successor":{"wt":""},"domain":{"wt":""},"license":{"wt":""},"copyright":{"wt":""},"website":{"wt":"{{URL|https://robotstxt.org}}, {{URL|https://datatracker.ietf.org/doc/html/rfc9309|RFC 9309}}"}},"i":0}}]}'>robots.txt Robots Exclusion Protocol Example of a simple robots.txt file, indicating that a user-agent called "Mallorybot" is not allowed to crawl any of the website's pages, and that other user-agents cannot crawl more than one page every 20 seconds, and are not allowed to crawl the "secret" folder Status Proposed Standard First published 1994 published, formally standardized in 2022 Authors Martijn Koster (original author) Gary Illyes, Henner Zeller, Lizzi Sassman (IETF contributors) Website robotstxt.org, RFC 9309 The Robots Exclusion Protocol (often referred to by the filename used to implement it, robots.txt) is a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the website they are allowed to visit. The standard, developed in 1994, relies on voluntary compliance. Malicious bots can use the file as a directory of which pages to visit, though standards bodies discourage countering this with security through obscurity. Some archival sites ignore robots.txt. The standard was used in the 1990s to mitigate server overload. In the 2020s, websites began denying bots that collect information for generative artificial intelligence. The "robots.txt" file can be used in conjunction with sitemaps, another robot inclusion standard for websites. History [edit] The standard was proposed by Martijn Koster,[1][2] when working for Nexor[3] in February 1994[4] on the www-talk mailing list, the main communication channel for WWW-related activities at the time. Charles Stross claims to have provoked Koster to suggest robots.txt, after he wrote a badly behaved web crawler that inadvertently caused a denial-of-service attack on Koster's server.[5] The standard, initially RobotsNotWanted.txt, allowed web developers to specify which bots should not access their website or which pages bots should not access. The internet was small enough in 1994 to maintain a complete list of all bots; server overload was a primary concern. By June 1994 it had become a de facto standard;[6] most complied, including those operated by search engines such as WebCrawler, Lycos, and AltaVista.[7] On July 1, 2019, Google announced the proposal of the Robots Exclusion Protocol as an official standard under Internet Engineering Task Force.[8] A proposed standard[9] was published in September 2022 as RFC 9309. Standard [edit] A site owner wishing to give instructions to web robots places a text file called robots.txt in the root of the web site hierarchy (e.g. https://www.example.com/robots.txt</nowiki>"}},"i":0}}]}'/>https://www.example.com/robots.txt). This text file contains the instructions in a specific format (see examples below). Robots that choose to follow the instructions try to fetch this file and read the instructions before fetching any other file from the website. If this file does not exist, web robots assume that the website owner does not wish to place any limitations on crawling the entire site. A robots.txt file contains instructions for bots indicating which web pages they can and cannot access. Robots.txt files are particularly important for web crawlers from search engines such as Google. A robots.txt file on a website will function as a request that specified robots ignore specified files or directories when crawling a site. This might be, for example, out of a preference for privacy from search engine results, or the belief that the content of the selected directories might be misleading or irrelevant to the categorization of the site as a whole, or out of a desire that an application only operates on certain data. Links to pages listed in robots.txt can still appear in search results if they are linked to from a page that is crawled.[10] Because compliant crawlers cannot access the blocked page, search results may display only the URL or other information available from external sources, since the crawler cannot retrieve the page's content.[11] A robots.txt file covers one origin. For websites with multiple subdomains, each subdomain must have its own robots.txt file. If example.com had a robots.txt file but foo.example.com did not, the rules that would apply for example.com would not apply to foo.example.com. In addition, each URI scheme and port needs its own robots.txt file; http://example.com/robots.txt</nowiki>"}},"i":0}}]}'/>http://example.com/robots.txt does not apply to pages under http://example.com:8080/</nowiki>"}},"i":0}}]}'/>http://example.com:8080/ or https://example.com/</nowiki>"}},"i":0}}]}'/>https://example.com/. Compliance [edit] The robots.txt protocol is widely complied with by bot operators.[6] The robots.txt played a role in the 1999 legal case of eBay v. Bidder's Edge,[12] where eBay attempted to block a bot that did not comply with robots.txt, and in May 2000 a court ordered the company operating the bot to stop crawling eBay's servers using any automatic means, by legal injunction on the basis of trespassing.[13][14][12] Bidder's Edge appealed the ruling, but agreed in March 2001 to drop the appeal, pay an undisclosed amount to eBay, and stop accessing eBay's auction information.[15][16] In 2007, Healthcare Advocates v. Harding, a company was sued for accessing protected web pages archived via The Wayback Machine, despite robots.txt rules that prevented those pages from being archived. A Pennsylvania court ruled "in this situation, the robots.txt file qualifies as a technological measure" under the DMCA. Due to a malfunction at Internet Archive, Harding could temporarily access these pages from the archive and thus the court found "the Harding firm did not circumvent the protective measure".[17][18][19] In 2013, Associated Press v. Meltwater U.S. Holdings, Inc. the Associated Press sued Meltwater for copyright infringement and misappropriation over copying of AP news items. Meltwater claimed that they did not require a license and that it was fair use, because the content was freely available and not protected by robots.txt. The court decided in March 2013 that "Meltwater’s copying is not protected by the fair use doctrine", mentioning among several factors that "failure […] to employ the robots.txt protocol did not give Meltwater […] license to copy and publish AP content".[20] Search engines [edit] Some major search engines following this standard include Google,[21] Bing,[22] Yahoo!,[23] Yandex,[24] DuckDuckGo,[25] Baidu,[26] AOL,[27] Ask,[28] and Kagi,[29] Archival sites [edit] Some web archiving projects ignore robots.txt. Archive Team uses the file to discover more links, such as sitemaps.[30] Co-founder Jason Scott said that "unchecked, and left alone, the robots.txt file ensures no mirroring or reference for items that may have general use and meaning beyond the website's context."[31] In 2017, the Internet Archive announced that it would stop complying with robots.txt directives.[32][6] According to Digital Trends, this followed widespread use of robots.txt to remove historical sites from search engine results, and contrasted with the nonprofit's aim to archive "snapshots" of the internet as it previously existed.[33] Artificial intelligence [edit] Starting in the 2020s, web operators began using robots.txt to deny access to bots collecting training data for generative AI. In 2023, Originality.AI found that 306 of the thousand most-visited websites blocked OpenAI's GPTBot in their robots.txt file and 85 blocked Google's Google-Extended. Many robots.txt files named GPTBot as the only bot explicitly disallowed on all pages. Denying access to GPTBot was common among news websites such as the BBC and The New York Times. In 2023, blog host Medium announced it would deny access to all artificial intelligence web crawlers as "AI companies have leached value from writers in order to spam Internet readers".[6] GPTBot complies with the robots.txt standard and advises web operators about how to disallow it, but The Verge's David Pierce said this only began after "training the underlying models that made it so powerful". Also, some bots are used both for search engines and artificial intelligence, and it may be impossible to block only one of these options.[6] 404 Media reported that companies like Anthropic and Perplexity.ai circumvented robots.txt by renaming or spinning up new scrapers to replace the ones that appeared on popular blocklists.[34] To help identify the growing number of web crawlers, Cloudflare maintains a public directory of known bot user agents, organized by category and operator.[35] In 2025, the nonprofit RSL Collective announced the launch of the Really Simple Licensing (RSL) open content licensing standard, allowing web publishers to set terms for AI bots in their robots.txt files. Participating companies at launch included Medium, Reddit, and Yahoo.[36][37][38] Security [edit] Despite the use of the terms allow and disallow, the protocol is purely advisory and relies on the compliance of the web robot; it cannot enforce any of what is stated in the file.[39] Malicious web robots are unlikely to honor robots.txt; some may even use the robots.txt as a guide to find disall…