opt-out
In plain wordsA way for creators, websites or individuals to say 'do not use my work or data to train AI' — instead of being asked for permission first, which would be opt-in.
AI training data
A mechanism by which rights holders or data subjects exclude their content or personal data from collection or use for AI training, inclusion being the default unless they act. Technical channels include robots.txtrobots.txt, n.: A small public file in which a website posts its rules for automated visitors, such as search-engine and AI crawlers, listing areas they are asked to stay out of. Obeying it is voluntary. rules aimed at AI crawlers, page-level meta tags and HTTP headers, machine-readable protocols such as TDMRep, registries of works not to be trained on, and dataset-specific tools such as the search-and-removal process of The StackThe Stack, prop. n.: A large free collection of computer source code from public repositories, selected mainly for permissive licenses and released from 2022 onward by the BigCode project for training coding models.; platforms also offer account settings that stop user content or chats from being used for training. In the EU, the general text-and-data-mining exception (Art. 4 of the 2019 Digital Single Market Directive) does not apply where rights holders have expressly reserved their rights 'in an appropriate manner, such as machine-readable means' for online content — the research exception of Art. 3 cannot be opted out of — and the AI Act requires providers of general-purpose AI modelsgeneral-purpose AI model, n.: The EU's legal name for the large, adaptable AI models behind chatbots and similar tools: models that can turn their hand to many different jobs and be built into many other products. to identify and respect such reservations. Opt-outs work only going forward, depend on crawler compliance and are hard to enforce against copies already circulating in existing datasets.
Our crawler checks both robots.txt and TDMRep headers before treating a page as opted out.
Origin
The AI-training sense spread in 2022–2023, when controversy over image generators prompted artist opt-out registries and 'noai' tags, and AI companies began publishing crawler names that robots.txt could block. EU law had already created a machine-readable reservation for text and data mining in the 2019 Copyright in the Digital Single Market Directive, Art. 4(3).
Usage note
Whether opt-out is adequate is disputed. Creators' groups argue for opt-in consent and payment; AI developers and some governments argue that opt-in would make large-scale training impractical. The UK's 2024–25 consultation on an exception with opt-out drew strong opposition from the creative industries.
Related
- robots.txtrobots.txt, n.: A small public file in which a website posts its rules for automated visitors, such as search-engine and AI crawlers, listing areas they are asked to stay out of. Obeying it is voluntary.
- text and data mining exceptiontext and data mining exception, n.: A rule in many countries' copyright laws that lets people use computers to copy and analyze large amounts of text, images or data without asking permission — sometimes only for research, sometimes unless owners opt out.
- data licensingdata licensing, n.: The legal permissions that say who may use a dataset or a body of content, for what purposes and on what terms — including whether it may be used to train AI.
- fair use and AI trainingfair use and AI training, phr.: The unsettled US legal question of whether AI companies may copy books, articles, pictures and music to train their models without permission, under the rule that allows some unlicensed uses of copyrighted work.
- web crawlerweb crawler, n.: A program that automatically travels the web, following links from page to page and downloading what it finds — used by search engines, archives and AI companies to gather data.
- General-Purpose AI Code of PracticeGeneral-Purpose AI Code of Practice, prop. n.: A voluntary rulebook, published by the EU in 2025, that makers of large AI models can sign to show they follow the EU AI Act's rules on transparency, copyright and safety.
Mentioned in
data licensingdata licensing, n.: The legal permissions that say who may use a dataset or a body of content, for what purposes and on what terms — including whether it may be used to train AI., data provenancedata provenance, n.: The documented history of a piece of data: where it came from, who created and changed it, under what permissions, and how it was processed before reaching an AI system., robots.txtrobots.txt, n.: A small public file in which a website posts its rules for automated visitors, such as search-engine and AI crawlers, listing areas they are asked to stay out of. Obeying it is voluntary., web crawlerweb crawler, n.: A program that automatically travels the web, following links from page to page and downloading what it finds — used by search engines, archives and AI companies to gather data., web scrapingweb scraping, n.: Using software to automatically copy information from websites — text, prices, images — in bulk, which is how much of the data used to train AI was gathered., The StackThe Stack, prop. n.: A large free collection of computer source code from public repositories, selected mainly for permissive licenses and released from 2022 onward by the BigCode project for training coding models.