GEO vs. AEO vs. SEO: what’s the difference?

All three describe work on the same website. What differs is where the result shows up and what gets counted. Here, a citation means that an AI answer links to your page as a source. The numbers in the “Sources” column refer to the source list at the end of this article.

Other names circulate for the same work, such as LLMO (large language model optimization) and AI SEO. Microsoft Advertising adds AIO: its article on AI search answers opens with “Whether you call it GEO, AIO, or SEO” (Microsoft Advertising, Oct 8, 2025). Our guide to generative engine optimization explains where the terms come from and what GEO covers in detail.

“AEO” deserves a second look. In EU customs, the same abbreviation stands for Authorised Economic Operator. Businesses established in the EU apply for this status with the customs authority of an EU country (European Commission, accessed Nov 7, 2026). So if a proposal mentions AEO, ask which one it means.

What does Google say?

Google describes its AI features as part of Search: they’re based on its core ranking and quality systems. From Google Search’s point of view, optimizing for generative AI search is therefore “still SEO.” Google explicitly names AEO and GEO as terms for work on visibility in AI search (Google Search Central, as of Jul 10, 2026).

To appear in AI Overviews and AI Mode, a page must be indexed and eligible to be shown with a snippet. Google names no other technical requirements (Google Search Central, AI features, as of Dec 10, 2025). As of August 31, 2026, any website can opt out of these features in Search Console. The default setting is “Include” (Google Search Console Help, AI control, Aug 31, 2026).

An llms.txt file is a text file with pointers for AI systems. For Google Search, Google considers it unnecessary. According to Google, you don’t need to rewrite your content specifically for AI or break it into small chunks. Chasing inauthentic mentions, Google says, “isn’t as helpful as it might seem.” Structured data, meaning machine-readable information in a page’s source code, isn’t required for generative AI search either. It still helps a page qualify for rich results, the enhanced listings in Google Search (Google, as of Jul 10, 2026).

What does Microsoft say?

Microsoft uses the term GEO itself. The Bing Webmaster Guidelines describe GEO as work on making content eligible to serve as the basis for AI answers and to be cited in them. Their first section says the SEO fundamentals apply to AI answers too: Bing and Copilot rely on the same crawling, indexing and ranking as traditional search. Just as SEO doesn’t guarantee rankings, Bing says, GEO doesn’t guarantee citations (Microsoft Bing, accessed Nov 7, 2026).

A Microsoft Advertising guide for retailers calls SEO and well-maintained product data the foundation for search with large language models. The guide says “traditional SEO remains essential” because AI systems frequently search the web in real time during the shopping journey (Microsoft Advertising, PDF dated Mar 24, 2026).

What does the research assume?

Even the study that coined the term GEO builds on search. For each query, its test setup fetched the top five Google results, and only then did the language model write its answer from them (Aggarwal et al., 2024). So the study measured what happens after the search.

Position counts at this stage, too. In a benchmark, most rewriting methods designed specifically for AI search had no effect or did harm. Moving a source higher up in the result list the model receives worked significantly better. The authors call this a traditional SEO strategy (Puerto et al., Oct 20, 2025). Across 252,000 trials with six language models, topical fit and position in the list did the most to decide which source got cited first (Vishwakarma et al., May 25, 2026). In both studies, the researchers chose which sources the model received. Neither shows whether this carries over to ChatGPT or Google.

One answer replaces many results. Organic search spreads conflicting statements across many results. An AI answer resolves them into a single statement, which can itself change over time (Kirsten et al., May 31, 2026). So in GEO, it also matters whether what the answers say about you is correct. In Germany, 42% of people who use AI for search say they’ve already received false or made-up information (Bitkom, Nov 20, 2025).

Individual passages count. Google Search already identifies individual sections of a page to judge how well the page matches a search (Google Search Central, ranking systems, as of Dec 10, 2025). According to Microsoft, assistants like Copilot break content down into smaller pieces and assemble the relevant ones into an answer. What gets ranked, it says, is less the whole page than the individual piece (Microsoft Advertising, Oct 8, 2025). Even so, according to Google, you don’t need to break your content into pieces yourself.

Sources also come from further down the results. In an analysis of 863,000 results pages, only 37.9% of the URLs that Google’s AI Overviews cited were among the top 10 results for the same search (Ahrefs, Mar 2, 2026). Ahrefs suspects the reason is query fan-out: the additional searches Google runs for a single question. In our view, that’s still SEO, just for more queries. Our article What is query fan-out? explains how these searches work, and you’ll find more measurements in our article on AI Overviews and AI Mode, under Do the cited pages come from the top 10?

More crawlers need access. Crawlers are the programs search engines and AI providers use to fetch web pages. For SEO, Googlebot and Bingbot are enough. AI providers send their own search crawlers, such as OAI-SearchBot (OpenAI), PerplexityBot and Claude-SearchBot (Anthropic). OpenAI says sites that block OAI-SearchBot won’t be shown in ChatGPT search answers, though they can still appear as navigational links (OpenAI, accessed Nov 7, 2026). Anthropic warns that blocking its crawler may reduce your visibility (Anthropic, Nov 4, 2026), and Perplexity recommends allowing its crawler (Perplexity, accessed Nov 7, 2026). What a block does is explained in our article on AI crawlers and robots.txt, under What happens if you block an AI crawler?

Mentions correlate more closely than links. Google’s core ranking systems analyze how pages link to each other, for example with PageRank (Google, as of Dec 10, 2025). For AI mentions, though, Ahrefs found only very weak correlations with link metrics across 75,000 brands. Brand mentions on the web (0.66–0.71) and on YouTube (about 0.74) correlated strongly. That’s a correlation, measured on websites with a Domain Rating above 40 (Ahrefs, Dec 12, 2025). Domain Rating is Ahrefs’ score for the strength of a website’s backlink profile (Ahrefs). The study doesn’t show whether the correlation holds for small businesses.

Strengths and limits of SEO

Strengths: Google and Microsoft document SEO in detail, and Search Console makes it measurable. Its basics are also a prerequisite for Google’s AI features and for Copilot.

Limits: Where Google shows an AI Overview, fewer people click. In Germany, 11% of searchers click the first result for such keywords, compared with more than 27% on average across all results pages (SISTRIX, Feb 25, 2026, updated Apr 2, 2026). No ranking shows whether an AI assistant mentions you.

Use case: always, as the foundation.

Strengths and limits of GEO

Strengths: GEO checks something no ranking shows: whether AI assistants mention your business and describe it correctly. It also puts the focus on mentions on other sites and on consistent company facts.

Limits: So far, effects are proven mainly for content the model already has. A survey of 45 studies found no technique with a stable, causal effect over time and across systems, either on whether pages get discovered or on how users behave (Martinez, Jul 15, 2026). Measurement takes more effort, and no one can guarantee a citation.

Use case: when your customers research thoroughly before they buy or hire, and AI answers don’t mention you or describe you incorrectly.

Where does that leave AEO?

AEO is older than GEO. As early as 2018, Search Engine Watch described AEO as optimizing for the one answer that voice assistants read aloud and featured snippets place above the results (Search Engine Watch, Feb 7, 2018). Google chooses featured snippets itself, and there’s no markup to request one (Google Search Central, featured snippets, as of Dec 10, 2025). In German search results, the two formats no longer appear together. Among 1,677,724 keywords in Germany with an AI Overview, Ahrefs found none whose results page also showed a featured snippet (Ahrefs, Aug 17, 2026). Today, Google names AEO and GEO as terms for the same work (Google, as of Jul 10, 2026). A 2026 study uses AEO for optimizing for ChatGPT (Watanabe and Nakayashiki, Jun 3, 2026).

Strength: The name stresses what matters: a clear answer.

Limit: The abbreviation is ambiguous.

Use case: You don’t need a separate discipline for it. If someone offers you AEO, ask exactly what they’ll measure. What to look for is covered in our how-to on choosing a GEO agency, under How do you check a GEO agency’s method?

The table shows what each tactic does for SEO and what it does for GEO. The “Evidence” column rates the statement about GEO. A means several independent primary sources or an explicit statement from the provider, B means single studies or vendor data, and C means indications that conflict. The ratings are our own assessment. Many of the figures come from makers of SEO and measurement tools, who have a stake in the topic.

IndexNow is a protocol websites use to notify Bing and other participating search engines of new, changed and deleted URLs (Microsoft Bing, Feb 10, 2026). Our guide rates other common claims, such as those about text length or refreshing the date, in its overview of GEO claims. Our article on llms.txt explains what the file can and can’t do.

Search Console: Google reports clicks and impressions from AI Overviews and AI Mode in the regular Performance report, under the “Web” search type (Google, as of Dec 10, 2025). There, all links in an AI Overview get the same position (Google Search Console Help, accessed Nov 7, 2026). Since August 31, 2026, the generative AI performance report has shown impressions in these features by page, country, date and device (Google Search Console Help, AI report, Aug 31, 2026).

Bing Webmaster Tools: Since February 2026, AI Performance has shown how often Copilot, AI-generated summaries in Bing and select partners cite your pages as a source. According to Bing, the figure reflects neither a page’s ranking nor its importance (Microsoft Bing, Feb 10, 2026).

A fixed set of questions: For all other systems, you have to measure yourself. In traditional search engines, a single query often shows where a page stands. For AI answers, that isn’t enough, because visibility there is a distribution across many runs (Schulte et al., Apr 8, 2026). When a test was repeated two months later, 45% of the links in the organic results were the same, but only 18% in AI Overviews. The test ran in 2025, with English queries from a US location (Kirsten et al., May 31, 2026).

Limits: Google says no third-party tool has access to its internal ranking or AI systems (Google, as of Jul 10, 2026). Figures on AI answers are therefore samples taken from the outside. Our how-to on measuring AI search visibility shows how to set up such a measurement.

Visits still come from search. StatCounter’s figures for Germany cover websites that use its tracking code. From November 2025 to October 2026, search engines accounted for more than 92% of referrals from search, social media and AI assistants in every month. AI assistants never accounted for more than 0.33% (StatCounter, accessed Nov 7, 2026). StatCounter says it counts clicks to websites, not searches (StatCounter FAQ).

Clicks are shifting. In Germany, AI Overviews cost about 6.6% of all organic clicks from Google, according to SISTRIX. Some categories barely lose any clicks, others almost a quarter. For long, specific keywords, an AI Overview appears more often: for about 30% of them (SISTRIX, Feb 25, 2026, updated Apr 2, 2026).

The question isn’t new. In 2018, an article on Search Engine Watch predicted that voice search would reach critical mass that year. The same article said “AEO is not going to replace SEO” (Search Engine Watch, Feb 7, 2018). Today, Google itself counts the work for its AI features as SEO. What’s new is the goal: besides the click, the mention in the answer counts too. That’s why Bing advises tracking impressions and citations as well, because fewer clicks don’t always mean less visibility (Microsoft Bing, accessed Nov 7, 2026). You’ll find more figures on our page AI search in Germany: key statistics.

1. Are your key pages indexed? Check in Google Search Console and Bing Webmaster Tools. If pages are missing, that’s an SEO task first. Our how-to Why isn’t my website showing up on Google? covers common causes.
2. Are search crawlers allowed in? Check your robots.txt for blocks on Googlebot, Bingbot, OAI-SearchBot, PerplexityBot and Claude-SearchBot. Ask your host whether your firewall and CDN, the network that delivers your pages, let these crawlers through.
3. Are your services in the HTML? Open the page source of your most important service page (Ctrl+U in many browsers) and search for a key sentence. If it’s missing, many AI crawlers won’t see it.
4. Do AI assistants mention you? Ask ChatGPT, Perplexity and Copilot 10 questions your customers ask. Note who gets mentioned and which pages appear as sources. Our how-to How to get your business recommended by ChatGPT walks you through it.
5. Are your company facts the same everywhere? Your name, address, services and point of contact should match on your website, in your Google Business Profile and in directories.
6. Who mentions you? Check which other sites carry your name, such as trade associations, industry media and review sites.
7. Do you measure regularly? Ask the 10 questions from step 4 several times every month.

If steps 1 to 3 are still open, start with SEO. That benefits both search results and AI answers. If they’re done and the answers from step 4 name other providers or get facts about you wrong, targeted GEO work pays off. We recommend this order because each step builds on the one before. No study has tested it as a whole. Our page on generative engine optimization services describes how we deliver and measure GEO.