GEO vs SEO vs AEO: what's actually different for agencies
Clear definitions of SEO, AEO and GEO, where they overlap, where they differ in tactics and measurement, and how to package them without confusing clients.
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SEO is optimising to rank in search engine results. AEO (answer engine optimisation) is optimising to be the answer — featured snippets, voice answers, and increasingly AI answers. GEO (generative engine optimisation) is optimising to be mentioned or cited inside answers written by AI systems like ChatGPT, Gemini and Perplexity.
In practice, AEO and GEO are used almost interchangeably in 2026, and both sit on top of SEO rather than replacing it. The useful differences for an agency are in what you measure and which sources you work on.
Where the terms come from
- SEO needs no introduction.
- AEO grew out of featured snippets and voice search: structure content so a search engine can lift a direct answer from it.
- GEO comes from a 2023 research paper by Aggarwal and colleagues (Princeton, Georgia Tech, the Allen Institute and IIT Delhi), published at KDD 2024. It tested content changes on a benchmark of queries and reported that some methods increased a source's visibility in generative answers by up to 40% — with results varying by domain.
There's no standards body, and agencies define the edges differently. Pick definitions you can explain in one sentence and use them consistently with clients.
The differences that matter
| SEO | AEO | GEO | |
|---|---|---|---|
| Goal | Rank a page in results | Be the extracted answer | Be mentioned or cited in a generated answer |
| Where it shows | Google/Bing result lists | Snippets, voice, AI answer boxes | ChatGPT, Gemini, Perplexity, AI Overviews, AI Mode |
| Unit of success | Position, clicks | Snippet won / answer shown | Mention rate, citation rate, share of voice |
| Stability | Fairly stable | Fairly stable | Varies answer to answer |
| Main levers | Pages, links, technical health | Answer-shaped content, structure | Pages that answer buyer questions, presence in cited sources, clear entity description, crawler access |
| Measured with | Rank trackers, Search Console | Rank trackers with SERP features | Repeated prompt tracking across engines |
Where they overlap
More than the hype suggests. Pages that are crawlable, well-structured, specific and trusted help in all three. AI systems that search the web read pages that search engines rank, so weak SEO tends to mean weak GEO. Many agencies sell GEO as an extension of SEO for exactly this reason.
Where GEO is genuinely different
- Sources outside the client's site matter more. Engines lean on review sites, comparison articles, directories and forums. Getting the client into the pages engines cite is often the biggest lever.
- Entity clarity matters. If the client is described inconsistently across the web, engines may not connect it to the category in the question.
- Measurement is statistical. There's no stable position. You ask the same questions repeatedly and report how often the client appears — see how to measure AI visibility.
- Each engine behaves differently. ChatGPT, Gemini and Perplexity search and cite differently; see ChatGPT vs Gemini vs Perplexity.
- Attribution is weaker. Many AI answers produce no click. You report visibility and AI referral traffic side by side.
How to explain it to a client
How to package it
- Keep one name. Pick GEO or AEO and use it everywhere — proposals, reports, invoices. Two names for one service is how clients get confused.
- Lead with measurement. A monthly AI visibility report on fixed buyer questions is the clearest proof the service exists. See the report template.
- Separate reporting from optimisation in the scope, so the client can see what's measurement and what's work.
Our playbook for selling GEO covers the pitch and the first 90 days.
Sources
- Aggarwal, P. et al. GEO: Generative Engine Optimization. KDD 2024.
Check a client’s AI visibility in about a minute
Enter a client’s website. Ranxii suggests buyer questions, asks a few of them on Perplexity and shows who gets mentioned — the client, a competitor, or nobody. No sign-up.
Keep reading
- How to sell GEO to your SEO clients: the offer, the pitch and the first 90 daysA practical playbook for adding generative engine optimization to an SEO agency: who to pitch first, how to open with evidence, what to include, objections and a 90-day plan.
- What AI visibility is, and how to measure it without fake precisionA practical definition of AI visibility and the six metrics worth reporting — mention rate, citation rate, share of voice, prompt coverage, engine split and sources — with what to avoid.
- ChatGPT vs Gemini vs Perplexity: why a client's AI visibility differs by engineThe same client can be recommended by Perplexity and ignored by ChatGPT. How each engine finds and cites sources, what that means for tracking, and what to check for each.