Answer engine optimization (AEO) is the work of getting your content picked as the direct answer to a question: in a featured snippet, a voice assistant's reply, or an AI answer from ChatGPT, Perplexity or Google's AI Overviews. Generative engine optimization (GEO) means almost the same thing, aimed at AI search. Both are industry labels with no official definition, and Google says that optimising for its AI search features is "still SEO". For the full picture of getting cited by AI search, read our guide to generative engine optimization.
This page is for marketers and site owners who are being pitched AEO, GEO or both and want to know what is behind the words. By the end you will know where each term comes from, what the AI operators actually document, and the handful of technical differences from classic SEO that are worth your time.
Quick answer
- AEO and GEO are marketing labels, not standards. No standards body, search engine or AI company publishes a definition or a specification for either.
- AEO is the older term. It grew out of featured snippets and voice assistants: pages written so a search engine can lift one clear answer from them.
- GEO comes from a 2023 research paper by Aggarwal and colleagues, published at KDD 2024, about getting cited inside answers written by a language model.
- Google treats both as SEO. Its guide to generative AI features names AEO and GEO and says that, from Google Search's perspective, the work is still SEO.
- A few things really differ: separate AI crawlers with their own robots.txt names, crawlers that do not run JavaScript, and measuring citations instead of positions.
- Check the technical part for free with the AI crawler check: which AI bots your robots.txt lets in and what they can read.
What is answer engine optimization?
An answer engine is any system that replies to a question with an answer instead of, or above, a list of links. The early examples were Google's featured snippets, the box above the results that quotes one passage from one page, and voice assistants that read a single answer aloud. Today the label also covers AI search products that write an answer and cite their sources.
Answer engine optimization is shaping a page so it becomes that answer. In practice the advice has always been similar: put the question in a heading, answer it in the first sentence under it, keep the answer short and factual, and support it with detail further down.
What AEO is not is a documented system. There is no AEO specification, no AEO markup and no AEO setting in any search engine or AI product. The word is used by agencies, tool vendors and writers, each with their own meaning.
What is generative engine optimization?
GEO has a clearer origin. The term was introduced in the paper GEO: Generative Engine Optimization by Pranjal Aggarwal, Vishvak Murahari, Tanmay Rajpurohit, Ashwin Kalyan, Karthik Narasimhan and Ameet Deshpande, first posted to arXiv in November 2023 (2311.09735) and accepted at KDD 2024. The authors built a benchmark of queries, ran it through a generative engine they controlled, and tested ways of rewriting source pages. Some methods, such as adding citations, quotations and statistics, raised a page's visibility in the generated answers by up to 40% in their setup, and the effect varied by subject.
That is a lab result on the authors' own engine, not a measurement of ChatGPT, Perplexity or Google. Since then "GEO" has spread into general use as a name for everything to do with AI search visibility, often far beyond what the paper tested. The generative engine optimization guide covers the whole process, from crawler access to measurement.
AEO vs GEO vs SEO at a glance
| SEO | AEO | GEO | |
|---|---|---|---|
| Goal | Rank a page in a list of results | Be the one answer shown or spoken | Be read and cited inside an AI-written answer |
| Where the term comes from | Search industry, 1990s | Search industry, the era of featured snippets and voice assistants | Aggarwal et al., arXiv 2023, KDD 2024 |
| Official definition | None, but search engines publish SEO guidance | None | None; the paper defines it for its own experiments |
| Main surfaces | Google, Bing and other search results | Featured snippets, voice assistants, AI answers | AI Overviews, AI Mode, ChatGPT search, Perplexity, Claude, Copilot |
| What Google says | Search Central documents it | Named in Google's AI guide as still SEO | Named in Google's AI guide as still SEO |
In everyday use, AEO and GEO overlap almost completely. Some writers use AEO for short, extractable answers and GEO for being cited in longer AI answers; others use the two interchangeably. Neither usage is wrong, because neither term has an owner.
What Google and the AI operators actually document
The strongest evidence on this topic is what the companies running the answer engines publish about their own systems. Here is what they say, as of September 2026.
- Google, "AI features and your website" (Search Central): there are no additional requirements to appear in AI Overviews or AI Mode, and no special optimisation is necessary. The page must be indexed and eligible to show a snippet. The controls are the usual
nosnippet,data-nosnippet,max-snippetandnoindex. - Google, "Optimizing your website for generative AI features on Google Search" (published May 2026): it names AEO and GEO directly and says that optimising for generative AI search is optimising for the search experience, "and thus still SEO". It adds that you do not need new machine-readable files, AI text files or special markup, that structured data is not required for its AI features, and that there is no need to break content into small pieces for AI.
- OpenAI: OAI-SearchBot is the crawler that surfaces sites in ChatGPT search, and sites that block it are not shown in ChatGPT search answers, although they can still appear as navigational links. GPTBot collects content for training and does not decide search visibility.
- Anthropic: ClaudeBot collects content for training, Claude-SearchBot crawls for search quality, and Claude-User fetches pages when a person asks. Each can be blocked separately in robots.txt.
- Perplexity: PerplexityBot surfaces and links sites in Perplexity's results and is not used to train foundation models. Perplexity-User fetches pages for a user's question and generally ignores robots.txt.
Nothing in any of these documents mentions an AEO score, a GEO ranking factor, or a file, tag or schema type that earns citations. Anyone who sells one is selling an opinion.
What actually differs technically
Strip away the labels, and four things are genuinely different when your goal is to be the answer rather than a blue link. Everything else, such as indexable pages, clear content and a fast, reliable server, is plain SEO.
1. There are more crawlers, with separate switches
Classic SEO deals with Googlebot and Bingbot. AI search adds a crawler per operator, and most operators split training from search. You can block GPTBot and ClaudeBot to stay out of model training and still allow OAI-SearchBot, Claude-SearchBot and PerplexityBot so those products can cite you. Google is different: AI Overviews and AI Mode use Googlebot and Search's index, and the Google-Extended token controls Gemini training and grounding, not Search. AI crawlers and robots.txt has ready-made robots.txt files for each choice.
2. Most AI crawlers do not run JavaScript
Google renders JavaScript for Search. An analysis of AI crawler traffic by Vercel and MERJ, published in December 2024, found that none of the major AI crawlers rendered JavaScript, including OpenAI's, Anthropic's and Perplexity's; Gemini was the exception because it uses Googlebot's rendering. If your text only appears after scripts run, most answer engines outside Google see an empty page. Server-side rendering or static HTML fixes it.
3. Snippet controls decide what can be quoted
In Google, the answer surfaces are built from snippets, so the snippet controls are also your AEO controls. nosnippet keeps a page out of snippets and AI features, data-nosnippet hides one part of a page, and max-snippet limits how much text may be quoted. Setting these for another reason, for example a max-snippet:0 left in a theme, quietly removes the page from answers.
4. Success is measured in citations, not positions
A ranking is a number you can track. An answer changes with the wording of the question, the user and the day. Google's Search Console now has a Generative AI performance report for impressions in AI Overviews and AI Mode; for other products you have referral traffic in analytics and prompt-tracking tools that sample answers. Treat those samples as trends, not rankings.
What is opinion, and fine to try
Some AEO and GEO advice is reasonable but not documented by any operator. Label it as such when you plan the work:
- Answer first, explain after. A question as a heading and a one-sentence answer under it is easy for any system to quote. No operator documents it as a ranking or citation factor.
- Facts with numbers and sources. The GEO paper found that statistics and citations helped in its setup. On a real site, "Delivery to Austria takes 2–4 working days and costs 8 EUR" is simply more useful than "fast delivery".
- Brand mentions on other sites. Widely believed to affect which brands AI answers name; no operator confirms it, and Google warns against manufacturing mentions.
- llms.txt. A proposal from llmstxt.org, not a standard. Google says creating such files neither helps nor harms visibility in Search, and no major AI search product has said it reads the file for citations. llms.txt: what it is and how to write one covers the format if you want one anyway.
- FAQ markup. Google limited FAQ rich results to government and health sites in 2023 and stopped showing them for every site on 7 May 2026, and says no special schema is needed for its AI features. FAQ and HowTo schema after Google's changes explains when it is still worth keeping.
How to check the technical part
The documented, technical differences are the ones you can test. The AI crawler check reads your robots.txt for 18 AI user agents from OpenAI, Anthropic, Google, Perplexity and others, grouped into training, AI search and user fetches. It validates /llms.txt if you have one, looks for AI opt-out tags, and compares the raw HTML with the rendered page to show how much of your text depends on JavaScript.
The same findings appear in every getReport report:
The check shows what your site tells each crawler and what they can read. It does not tell you whether ChatGPT or Perplexity actually cites you, or for which questions; no crawler test can.
If you decide to publish an llms.txt, the generator drafts one from your sitemap, with real page titles grouped into sections, and checks it against the llmstxt.org format while you edit it in your browser:
Common mistakes
- Buying AEO and GEO as two separate projects. They cover the same pages and the same fixes. Ask what the second one would change that the first did not.
- Blocking every AI bot, then asking why you are not cited. A single rule for "AI bots" usually blocks the search crawlers along with the training ones.
- Blocking Google-Extended to leave AI Overviews. It does not do that. AI Overviews follow your Search settings and snippet controls.
- Rewriting every page into tiny chunks. Google says there is no need. Clear headings and direct answers help; chopping a good page apart does not.
- Treating a tool's "AEO score" as a measurement. No operator publishes such a score. Ask what it is calculated from.
Questions people ask
What is answer engine optimization?
Answer engine optimization (AEO) is the work of making your content the direct answer a system gives to a question, in a featured snippet, a voice assistant or an AI answer. It means letting the right crawlers in, serving text in plain HTML and answering questions clearly under matching headings. It is an industry label, not a standard, and Google treats it as part of SEO.
What is the difference between AEO and GEO?
Mostly the era they come from. AEO grew out of featured snippets and voice assistants and focuses on being the single extracted answer. GEO comes from a 2023 research paper and focuses on being cited in answers written by language models. The technical work behind both is the same: crawler access, readable HTML, indexable pages and clear, factual writing.
Is answer engine optimization the same as SEO?
Largely, yes. Google's guide to its generative AI features names AEO and GEO and says the work is still SEO. What is genuinely extra is small: deciding which AI crawlers to allow, making sure text does not depend on JavaScript, checking snippet controls, and measuring citations as well as rankings. A page that deserves to rank is usually the page that gets quoted.
Is there an official definition of AEO or GEO?
No. No search engine, AI company or standards body publishes a definition or specification for either term. Google mentions both only to say they are still SEO. GEO is defined in the 2023 paper by Aggarwal and colleagues, but only for its own experiments. When a vendor uses either word, ask exactly what they will measure and change.
Who coined the term generative engine optimization?
A team led by Pranjal Aggarwal, with researchers from Princeton University and other institutions, in the paper "GEO: Generative Engine Optimization". It was posted to arXiv in November 2023 and accepted at KDD 2024. Their tests found that adding citations, quotations and statistics raised visibility by up to 40% on the authors' own engine.
Do featured snippets still matter for answer engine optimization?
Yes, as a sign that Google can lift a clear answer from your page. Featured snippets and AI Overviews both draw on Search's index and obey the same snippet controls, so a page with nosnippet or max-snippet:0 is shut out of both. Writing a direct answer under each question heading helps with either, although neither placement is guaranteed.
What should I ask before paying for AEO or GEO services?
Ask which surfaces they target, what they will change on your site, and how they measure the result. Good answers mention crawler access, rendering, indexing and content. Be wary of a proprietary score, a guaranteed citation, or a special file or markup presented as required, because Google and the AI operators document no such thing.