AEO vs GEO vs SEO: What's the Difference?

SEO is about ranking your pages in search results, while AEO (answer engine optimization) and GEO (generative engine optimization) are both about getting your brand and content into the answers AI tools write. In practice AEO and GEO are two names for the same job, and most of that job is shared with SEO.

The labels matter less than vendors suggest. Answer engines that search the web retrieve from search indexes, so the foundations are the same: crawlable pages, authority, relevance and clear writing. What changes is where you look for results, which pages count towards them, and how you measure progress.

This guide explains where each term came from, maps the overlap, and ends with a decision guide for where to spend effort. For a fuller definition of AEO on its own, see what is answer engine optimization.

Where each term comes from

SEO

Search engine optimization has been around nearly as long as commercial web search. Its goal is well understood: help search engines crawl, index and rank your pages so people click through from a list of results. The methods have changed many times, but the outcome it measures (positions and clicks) hasn't.

AEO

"Answer engine" predates ChatGPT. SEOs used the phrase for featured snippets, knowledge panels and voice assistants that read out a single answer instead of a list. Generative AI gave the term a bigger target: written answers from ChatGPT, Perplexity, Claude, Copilot and Google's AI features. AEO is an industry term with no single owner or formal definition, which is partly why it gets used loosely.

GEO

GEO has a clear origin. The paper GEO: Generative Engine Optimization, by Pranjal Aggarwal and colleagues, was first posted to arXiv in November 2023 and accepted to KDD 2024. It defines generative engines as systems that retrieve sources and use large language models to write a response grounded in them, proposes GEO as a way for content creators to improve their visibility in those responses, and introduces a benchmark of queries called GEO-bench.

The paper tested nine ways of rewriting source content, on a generative engine the authors built and on Perplexity. Adding citations to sources, quotations and statistics were its strongest methods. Keyword stuffing, a classic old-school SEO tactic, offered little or no improvement, and results varied by subject area. Treat this as evidence about writing style from a research benchmark, not a recipe: commercial engines have changed a lot since it was run.

The other labels

You'll also see LLMO (large language model optimization), "AI SEO" and "AI search optimization". They describe the same goal. When an agency pitches one of these as distinct from the others, ask what they would do differently; the answer is usually nothing.

How much the three overlap

Most of the work is the same whichever label you use. All three depend on:

• Pages that search crawlers can reach and search engines index
• Authority, which still comes largely from links and coverage on trusted sites
• Topical relevance to the questions people actually ask
• Clear, specific content that states facts plainly
• A consistent description of who you are and what you do

The genuine differences are narrower:

• The output. SEO targets a list of links. AEO and GEO target a written answer that may cite several sources and may not need a click.
• Whose pages count. SEO mostly measures your own URLs. AEO and GEO also count third-party pages that mention you, because an answer can name you while citing a publication.
• Which crawlers matter. SEO is mostly Googlebot and Bingbot. AI answers add OpenAI, Anthropic and Perplexity's own search crawlers.
• How you measure. SEO uses rank tracking and Search Console. AEO and GEO add prompt tracking, AI referral traffic and crawler logs.

Google's own position is blunt. Its guide to optimizing for generative AI search names both AEO and GEO and says that, from Google Search's perspective, optimizing for its generative AI features is still SEO. That's Google describing Google's products. Other engines run their own crawlers and indexes, and that's where the differences above come from.

Why most of the work is shared

The overlap isn't a coincidence; it follows from how answer engines work. Google documents that AI Overviews and AI Mode draw on its search index, and Microsoft grounds Copilot's web answers in Bing. OpenAI, Perplexity and Anthropic run their own search crawlers. In every case, an engine retrieves candidate pages from an index before writing anything, so a page that's weak in search is usually weak in answers too. How AI answer engines choose sources covers what each engine documents.

That's also why a single well-chosen asset can serve all three labels at once. Take a placement article on a respected industry publication:

• For SEO, its link to your site is a signal that helps your own pages rank.
• For AEO, the article is a page on a trusted domain that engines can retrieve for questions about your category.
• For GEO, a passage that cites a source, quotes an expert or states a specific figure is the kind of content the GEO paper found most visible.

None of these effects is guaranteed, but they stack. How backlinks help your brand get cited follows that chain step by step.

Where the work actually differs

Four areas need attention beyond a standard SEO plan.

Crawler access beyond Google and Bing

AI companies run separate crawlers for search and for model training. A robots.txt written years ago, or a firewall rule added last month, can block an AI search crawler while Googlebot sails through. How to configure robots.txt for AI crawlers explains which bots to allow for which purpose.

Presence on third-party sources

For "best", "versus" and "is it legit" questions, engines tend to cite independent publications and reviews. Being described accurately on those sources counts for more in AEO than in classic SEO, where the link is the main prize. What makes a publication citable shows how to pick them.

Writing for passages, not pages

Answers quote a sentence or two, not a whole page. Content written so that each key fact stands on its own, with the brand and category named, is easier to extract.

Measuring answers instead of rankings

Google now offers a Generative AI performance report in Search Console showing impressions in AI Overviews and AI Mode. For other engines you need a fixed prompt set run on a schedule, plus AI referral traffic and crawler logs. How to measure AI citations sets out a workable method.

A simple decision guide

Rather than choosing between SEO, AEO and GEO, find your current bottleneck and work on that. Start at the top and stop at the first statement that's true for you.

1. Your key pages aren't indexed or don't rank for anything relevant. Start with SEO basics: technical health, pages that answer real questions, and links to your important pages. AI work built on an invisible site has little to retrieve.
2. AI crawlers are blocked on your site. Fix robots.txt and firewall rules first. It's the cheapest change you can make, with the most direct effect.
3. You rank well, but AI answers name competitors. Look at the pages those answers cite. If they're third-party roundups and publications, the work is mostly off-site: get described accurately on those sources.
4. AI answers mention you, but vaguely or wrongly. Make your description consistent: the same plain statement of what you do, for whom, on your site, your profiles and third-party coverage.
5. You appear in one engine but not others. Check engine-specific access and the index each engine relies on: Google for AI Overviews, Bing for Copilot, and their own crawlers for ChatGPT, Perplexity and Claude.
6. All of the above is in place. Widen coverage across more relevant publications in your niche, and keep measuring.

There's no published formula for splitting budget between these stages, and anyone quoting one is guessing. A team stuck at step one gets little from placements; a team at step three gets little from another technical audit. If you're at step three or beyond, the plan recommender builds a budget-fitted placement plan from your industry, goal and target market.