What is generative engine optimisation and why does it matter?

What is generative engine optimisation?

Generative engine optimisation, or GEO, is the practice of making your website visible in AI-generated search results. Where traditional SEO focuses on ranking in Google’s list of blue links, GEO focuses on appearing as a cited source when AI tools like ChatGPT, Perplexity, Gemini, or Copilot generate an answer to a user’s question.

The distinction matters because the two channels work differently. Google ranks pages. AI systems cite sources. Getting cited requires a different set of signals and a different approach to how you structure and present your content.

Why GEO matters now

AI search is not a future consideration. It is happening now. A growing proportion of searches never reach a traditional search results page at all - the user asks an AI tool, gets an answer with cited sources, and either clicks through to one of those sources or does not need to search further.

For businesses, this creates a new visibility problem. You can rank well in Google and be completely absent from AI-generated answers. The signals that determine AI citation are different from the signals that determine Google rankings, and most websites have not been optimised for them.

The businesses that appear in AI-generated answers are not necessarily the biggest or the best known. They are the ones whose websites send the right signals - structured data, clear entity information, question-led content, and a consistent brand presence across the web.

How AI search systems work

Understanding GEO requires a basic understanding of how AI search systems generate their answers.

Most AI search tools use a combination of two things: a large language model trained on web data, and a retrieval system that searches the live web to find current sources. Perplexity is almost entirely retrieval-based - it searches the web in real time and cites the sources it finds. ChatGPT with browsing enabled uses Bing’s index as its primary retrieval source. Gemini draws on Google’s index. Claude uses a combination of training data and web search.

This means there are two ways to influence AI visibility: appearing in the training data, and appearing in the live retrieval results. The live retrieval layer is where most businesses can have the most immediate impact, and it responds to many of the same signals as traditional SEO - authority, relevance, and technical quality - combined with AI-specific signals like schema markup and content structure.

The five signals that determine AI citation

1. Schema markup

Schema markup is structured data that tells search engines and AI systems exactly what your business does, who you are, and how to categorise your content. AI systems use schema as a primary signal when deciding whether to cite a source.

The most important schema types for GEO are Organisation, WebSite, Service, FAQPage, and Article. Most websites either have no schema at all or have it implemented incorrectly. Getting this right is one of the highest-impact GEO improvements you can make.

2. Entity consistency

AI systems think in entities - coherent, consistent representations of real-world things like businesses, people, and places. For your business to be confidently cited by an AI system, it needs to exist as a consistent entity across the web.

This means your business name, description, address, and contact details should be identical everywhere they appear - your website, Google Business Profile, LinkedIn, industry directories, and any other platform where your business is mentioned. Inconsistencies create uncertainty for AI systems and reduce the likelihood of citation.

3. Question-led content structure

AI systems extract from content that answers questions directly and clearly. A page that opens with a direct answer to a specific question, uses clear heading hierarchy, and includes a well-structured FAQ section is significantly more likely to be cited than a page that buries its key information in long, unstructured paragraphs.

This does not mean writing differently for AI systems. It means writing clearly for humans - which is also what AI systems reward.

4. llms.txt

llms.txt is a plain text file placed at the root of your domain that tells AI crawlers what your site is about and which content is most useful to index. Several major AI systems already check for this file. It is the AI equivalent of robots.txt and it is a simple but effective signal that your site is aware of and optimised for AI search.

5. Third-party citations and authority

AI systems draw on what the wider web says about your business, not just what your own website says. Being mentioned in industry publications, directories, and authoritative third-party sources increases both the likelihood of appearing in training data and the authority signals that influence live retrieval results.

GEO versus traditional SEO: what is different

Traditional SEO and GEO share common foundations - technical quality, content relevance, and authority signals all matter in both. But there are important differences.

Traditional SEO optimises for ranking algorithms that evaluate hundreds of signals to produce an ordered list of results. GEO optimises for AI systems that decide whether to cite a source at all when generating a specific answer.

The content requirements are different. For traditional SEO, content length, keyword density, and backlink profiles are significant factors. For GEO, directness, structure, and schema implementation matter more. A short, well-structured page that answers a specific question clearly can outperform a long, comprehensive article for AI citation purposes.

The measurement is different too. You cannot check your AI citation ranking in Search Console. Testing requires manually querying AI systems with relevant questions and documenting whether your site is cited.

What UK businesses need to do

GEO is not a replacement for traditional SEO. It is an additional layer that ensures your visibility extends to the AI search tools your customers are already using.

The practical steps for most UK businesses are:

1. Implement comprehensive schema markup across your site. Start with Organisation and WebSite schema on every page, then add Service, FAQPage, and Article schema where relevant.
2. Audit your entity consistency. Check that your business name, description, and details are identical across every platform where you appear.
3. Add an llms.txt file to your domain root. Keep it updated with accurate information about your business and your key pages.
4. Restructure your key pages to answer questions directly. Add FAQ sections to your service pages and make sure each section opens with a clear, direct answer to the question it addresses.
5. Build third-party citations. Get listed in relevant directories, seek coverage in industry publications, and make sure your Google Business Profile is complete and accurate.
6. Test your current visibility. Ask ChatGPT, Perplexity, and Gemini questions that your target customers would ask and see whether your business appears. Document where you do and do not show up - that is your baseline.

How long does GEO take to work?

Schema and llms.txt changes can be picked up by AI crawlers within days. Appearing consistently in AI-generated answers typically takes four to eight weeks as systems re-crawl and update their responses.

The businesses that will benefit most from GEO are the ones that start now. The channel is less crowded than traditional SEO, the signals are relatively straightforward to implement, and the gap between businesses that have optimised for AI search and those that have not is currently very wide.

Frequently asked questions about GEO

What does GEO stand for?

GEO stands for generative engine optimisation. It refers to the practice of optimising websites to appear as cited sources in AI-generated search results.

Is GEO the same as AEO?

AEO stands for answer engine optimisation and is used by some practitioners to describe similar concepts. The terms are broadly interchangeable, though GEO is increasingly the more widely used term as it specifically references the generative AI systems driving the change.

Do I need GEO if I already rank well in Google?

Yes. Google rankings and AI citation are separate. A site can rank first in Google for a query and be completely absent from AI-generated answers about the same topic. The signals are different enough that one does not guarantee the other.

Which AI systems should I optimise for?

The main systems to focus on are ChatGPT, Perplexity, Gemini, Copilot, and Claude. Perplexity is the most citation-heavy and often the quickest to reflect new content. ChatGPT with browsing uses Bing’s index. Gemini draws on Google’s index.

Can I do GEO myself?

Some elements - like adding an llms.txt file or restructuring content - are straightforward to implement. Schema markup requires technical knowledge to implement correctly and comprehensively. A GEO audit from a specialist will give you a clear picture of where you stand and what needs doing.