SEO, AEO and GEO are three labels for closely related work. SEO (search engine optimization) aims to rank pages in search results. AEO (answer engine optimization) aims to have your content quoted in direct answers. GEO (generative engine optimization) aims to be cited or mentioned in answers written by AI models. They share one foundation: a site that is crawlable, clear and trusted.
It is worth saying up front that AEO and GEO are informal industry terms. There is no standards body behind them, and different writers draw the lines in different places. This post compares them as they are commonly used, and explains why the difference matters less than the shared work.
The three labels in one table
| SEO | AEO | GEO | |
|---|---|---|---|
| Target | Search result pages | Direct answers | Generated AI answers |
| Unit of success | A ranked page | A quoted passage | A cited or mentioned source |
| Main surface | Search engines | Assistants and answer boxes | Chat assistants and AI search |
| Shared basics | Crawlable, clear, trusted | Crawlable, clear, trusted | Crawlable, clear, trusted |
The table shows the main difference: what counts as a win. In SEO, success is a ranked page that a person clicks. In AEO and GEO, success is often a passage or a mention inside an answer, which the reader may never click through.
SEO: rank the page
Search engine optimization is the oldest of the three and the best documented. Search engines publish guidance on crawling, indexing and quality, such as Google Search Central. The work covers technical health (crawlability, speed, mobile), on-page content, structured data and links from other sites.
The unit of success is a page ranking for a query. The reader sees a list, chooses a result and lands on your site.
AEO: be the answer
Answer engine optimization started with featured snippets and voice assistants, where one answer is read out or shown above the results. It now includes AI assistants that answer in full sentences and cite sources.
The unit of success is a passage. That changes how you write: answer the question in the first sentence, give each idea its own short section, define terms plainly. We cover the technique in writing content AI assistants quote and the basics in what is answer engine optimization.
GEO: be cited by generative models
Generative engine optimization is the newest label. It focuses on answers written by large language models, in chat assistants and AI search features. People use it to mean being cited as a source, being mentioned by name, or both.
In practice GEO and AEO describe nearly the same work. Where some writers separate them, GEO tends to put more weight on brand mentions across the web and on content the model may have learned from during training, while AEO focuses on retrieval at question time. Both depend on the same inputs.
Where they overlap
Most answer engines retrieve from a web index before they write. If your page is not crawlable, not indexed or not trusted, it is not in the pool the answer is drawn from. That is why the shared foundation carries most of the weight.
- Crawl access: search crawlers and AI crawlers both need permission and a page they can read. See robots.txt for AI crawlers.
- Helpful content: specific, accurate, written for people.
- Structure: headings, lists and tables help ranking systems and retrieval chunking alike.
- Structured data: JSON-LD states entities and facts explicitly. See JSON-LD schema that matters.
- Authority: links, mentions and a clear identity behind the site.
Where they differ in practice
A few things do shift when the target is an answer rather than a ranking:
- Passage design: a strong page can still lose to a weaker page with one clearer paragraph. Write sections that stand alone.
- Machine-readable extras: files such as llms.txt and Markdown versions of pages exist for language models, not search engines. They are cheap to add.
- Usage signals: Content Signals let you say whether your content may be used for search, for AI answers or for training. That choice does not exist in classic SEO.
- Measurement: rankings and clicks are well tooled. Visibility inside AI answers is not. See measuring visibility in AI answers.
A practical split of the work
If you have to divide effort, a sensible order is:
- Technical access (all three): crawlable pages, text in the HTML, correct robots.txt rules for search and AI crawlers, a sitemap.
- Content that answers questions (all three, weighted toward AEO and GEO): answer-first sections, headings that match real questions, plain definitions.
- Entity clarity (all three): one consistent name, an Organization entity in JSON-LD, official profiles linked with
sameAs. - Machine-readable extras (AEO and GEO): llms.txt, Markdown on request, Content Signals.
- Measurement (each has its own): search tools for SEO, referrals, logs and a prompt panel for answers.
Steps one to three are where most sites have the biggest gaps, and they pay off whichever label you care about.
What to do with this
Treat the three labels as one programme with a few extra steps, not three budgets. Get the foundation right, then add the answer-focused writing and the machine-readable files.
Be cautious of anyone selling a guaranteed placement in AI answers. The systems choose their sources, the choice changes over time, and nobody outside the provider controls it. What you can promise is a site that gives those systems every reason to use you.
Choosing who helps you
If you hire help, ask what they will change on your site, not which label they sell. Good answers name specific work: fixing crawl rules, rewriting openings, adding structured data, publishing llms.txt. Be careful with promises of a fixed share of AI answers or rankings within a set time, because nobody outside the search and AI providers controls those outcomes.
Next step
The free agent-readiness scan checks the machine-readable side in one pass: robots.txt rules for AI crawlers, llms.txt, Markdown on request, structured data and more. For content and technical work across search and answers, see our SEO service.