What is GEO, generative engine optimization?
GEO, generative engine optimization, is the work of getting AI assistants such as ChatGPT, Gemini and Perplexity to name and cite you in their answers. AEO, answer engine optimization, covers the same ground, and both stand on SEO: an AI answer can only quote pages its crawlers reach and read.
Checked against the studies and help pages it cites on October 9, 2026.
Where GEO sits beside SEO and AEO.
GEO sits beside two older names. All three aim to put your site in front of people who ask a question; they differ in where the answer appears and what counts as a win. The comparison of AEO, GEO and SEO goes through what changes in the work.
SEO: rank in the results
Search engine optimization gets a page into Google's and Bing's results and earns the click. You measure it in rankings, clicks and visits.
AEO: be the answer
Answer engine optimization shapes a page so an engine can lift a direct answer from it, in a featured snippet, a voice reply or an AI answer. Many people use AEO and GEO for the same work.
GEO: be named and cited
Generative engine optimization gets AI assistants that write their answers, such as ChatGPT, Gemini, Perplexity and Google's AI Overviews, to name your brand and cite your pages. A 2023 paper by researchers from Princeton and IIT Delhi introduced the term.[1]
What all three need
Pages that crawlers can reach and read, with a clear answer to the question someone asked.
What the research and our data show.
Numbers from two published studies and from our own study of the sites AI answers cite.
more visibility in generated answers when the GEO paper's authors added quotations, statistics or cited sources to a page.[1]
chance that ChatGPT or Google's AI gives the same list of brands twice, in SparkToro's study of 2,961 runs.[2]
of the cited pages we rendered show at least 99.5% of their main text in the HTML, where crawlers that skip JavaScript can read it.
of cited sites block OAI-SearchBot, the crawler ChatGPT search reads through, against 3.1% for GPTBot, OpenAI's training crawler.
The GEO paper ran its tests on a test engine built on GPT-3.5 and on Perplexity; 41% is its best method's gain on its main measure.[1] SparkToro and Gumshoe's study isn't peer-reviewed, and Gumshoe sells AI tracking.[2]
Our figures come from the 1,605 sites cited in 1,033 AI answers we recorded in October 2026, whose robots.txt we read as GEOFastBot. Shares are of the 1,529 of 1,605 sites whose robots.txt we could read, or that have none; 62 refused our request. We also rendered up to 3 cited pages from 1,505 of the sites in Chrome; 2,022 rendered cleanly.
What carries over from SEO.
An AI answer can only quote a page its crawler fetched and could read. That part of SEO still decides who gets in.
Crawlers must get in
AI companies run their own crawlers, such as OAI-SearchBot for ChatGPT search and PerplexityBot for Perplexity, and each answers to its own name in robots.txt.[3, 4] The crawler guide says which to allow.
Text must be in the HTML
Vercel's 2024 study found OpenAI's, Anthropic's and Perplexity's crawlers fetching pages without running JavaScript, so text that scripts add is missing for them.[5] The rendering guide has the fixes.
Google's AI uses Google's index
Google says SEO best practices still apply to AI Overviews and AI Mode, and that you need no new files or markup to appear in them.[6]
What's different about AI answers.
A results page lists ten links in a set order. An AI answer names a few brands and cites a few pages, and the next answer can differ.
Answers move from ask to ask
In SparkToro's study, ChatGPT named City of Hope in 69 of 71 answers to one prompt, and put it first in 25.[2] The ChatGPT guide shows how to check your own brand by hand.
A mention can come without a click
An answer can name you and send no visitor. So GEO counts how often answers name you, put you first and cite your pages, next to the traffic you already track.
What helps, so far
In the GEO paper's tests, pages gained the most when the authors added quotations, statistics and cited sources. Keyword stuffing did worse than leaving the page alone in their main test.[1]
What hasn't shown an effect
SE Ranking's study of 300,000 domains found no link between having an llms.txt file and how often AI answers cite a site.[7]
How to tell whether GEO is working.
One chat proves little. Ask the same questions the same way, many times, and count the answers.
Mention rate
The share of answers that name you, with a range that narrows as the answers add up.
First pick
The share of answers that offer you first. Answers rarely order brands the same way twice, so a rate tells you more than one position.
Citations
The share of answers whose sources include a page on your site: the answers that can send you visitors.
Share of voice
Share of voice sets your mentions against the competitors you track, so you see who AI names when it doesn't name you.
A free first look
GEOFast's free GEO audit checks what AI crawlers can read on your site. It then asks ChatGPT, Perplexity and Gemini three buyer questions once each, and with a free account six once each: 18 answers, a first look rather than a measurement.
Questions about GEO.
Is GEO the same as AEO?
Close enough that most advice fits both. AEO, answer engine optimization, is about getting any engine to use your page as its answer. GEO is about AI assistants that write their answers, such as ChatGPT, Gemini and Perplexity. AEO vs GEO vs SEO, compared
Does GEO replace SEO?
No. AI answers draw on pages that crawlers can reach and read, and Google says SEO best practices still apply to AI Overviews and AI Mode. GEO adds goals on top: being named, being first and being cited.
What is a GEO tool?
Software that checks whether AI crawlers can read your site, or that asks AI assistants your buyers' questions and counts the answers that name you. GEOFast's free X-ray does both, as a first look.
Does llms.txt help with GEO?
Not that anyone has shown. SE Ranking found no link between the file and AI citations across 300,000 domains, and Google says AI Overviews need no special files or markup.
Where do I start?
Check that AI crawlers can reach and read your site, then put the answer a buyer wants at the top of the page that should win it. The free GEO audit checks the first part in about a minute. Run the free GEO audit
Where each fact comes from.
Each numbered source is the page a fact comes from: published studies and the AI companies' own help pages, read on October 9, 2026. The answers above repeat facts marked in the guide. Help pages change, so check them before you act.
- 1Aggarwal et al., KDD 2024: GEO: Generative Engine Optimizationarxiv.org/abs/2311.09735
- 2SparkToro: NEW Research: AIs are highly inconsistent when recommending brands or products; marketers should take care when tracking AI visibilitysparktoro.com/blog/new-research-ais-are-highly-inconsistent-when-recommending-brands-or-products-marketers-should-take-care-when-tracking-ai-visibility/
- 3OpenAI: Overview of OpenAI Crawlersdevelopers.openai.com/api/docs/bots
- 4Perplexity: Perplexity Crawlersdocs.perplexity.ai/docs/resources/perplexity-crawlers
- 5Vercel: The rise of the AI crawlervercel.com/blog/the-rise-of-the-ai-crawler
- 6Google: AI Features and Your Websitedevelopers.google.com/search/docs/appearance/ai-features
- 7SE Ranking: Does LLMs.txt impact your AI visibility and citations? No, according to researchseranking.com/blog/llms-txt/
Keep reading
- The free GEO auditA free GEO audit of up to 300 pages: AI crawler access, JavaScript rendering, 21 checks and fixes ranked by impact, with code. No sign-up.
- AI share of voice: who AI answers nameAI share of voice: who AI names when buyers ask, your share of mentions against the competitors you track, with a range, and the brands you don't track.
- AI visibility tools, comparedEvery tool we have checked, by starting price.
- AEO and GEO tools, comparedTools that audit your site and track the answers.
- AEO vs GEO vs SEOAEO vs GEO vs SEO: where each name came from, what Google and Microsoft say, the work all three share, and the four things that change with AI answers.
- Check if ChatGPT mentions your brandCheck by hand in five steps, see why one chat can't measure it (answers change, memory, location, leading questions), and where ChatGPT and Claude do help.
- Find the competitors ChatGPT recommendsA method for finding who ChatGPT recommends instead of you: which questions to ask, how many times, how to count the names and work out your share of voice.
- Does ChatGPT give everyone the same answer?No. ChatGPT writes each answer afresh and can use your memory, location, a web search and your plan's model. OpenAI's own pages, and our repeat-run numbers.
- AI visibility metricsMention rate, first-pick rate, citation rate, share of voice and sentiment: what each one counts, how to work it out, and why each needs a range.
- Get ChatGPT to recommend your businessWhat gets a business named in ChatGPT's answers: what you control, whether you can submit your business, how long changes take, and how to measure it honestly.
- Get cited by ChatGPTHow ChatGPT search finds and picks the pages it links, from OpenAI's docs, what makes a page usable as a source, and which kinds of pages our data shows cited.
- Why ChatGPT doesn't show your websiteSix reasons ChatGPT leaves a site out, in the order to check them: robots.txt, firewalls, noindex, JavaScript, Bing's index and who the pages it reads name.
- Does ChatGPT use Google or Bing?What OpenAI documents about where ChatGPT search gets results (Bing, its own crawler and index), what is only reported about Google, and what it means for you.
- Rank in Google's AI OverviewsWhat Google says you need to show up in AI Overviews, how query fan-out and nosnippet work, and what studies show: 38% of cited pages rank in the top 10.
- Rank in Google AI ModeWhat sets Google's AI Mode apart from AI Overviews: query fan-out, follow-ups, a custom Gemini and Search Console's counts, and how often the two cite one page.
- Perplexity SEOHow Perplexity finds, reads and cites pages: its two crawlers, what its docs say and leave out, the Cloudflare dispute, studies, and what our runs show.
- Which AI crawlers to allowWhich AI crawlers feed ChatGPT, Claude, Perplexity and Google's answers, which only train models, and what the 1,529 of 1,605 cited sites we could read allow.
- robots.txt for AI crawlersCopy-ready robots.txt rules that keep AI search crawlers in and training crawlers out, how each crawler reads the file, and the mistakes that lock AI out.
- What is llms.txt?llms.txt is a Markdown file that tells AI agents what a site holds. Its format, a real example, who reads it today, and what studies show about its effect.
- Firewalls that block AI crawlersCloudflare, Vercel, AWS WAF and others can turn AI crawlers away even when robots.txt lets them in. Where each setting lives and how to let crawlers through.
- Do AI crawlers render JavaScript?Google's and Bing's crawlers render JavaScript. OpenAI, Anthropic and Perplexity don't say, and Vercel's 2024 study found theirs don't. Our data on cited pages.
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