If you type your brand name into ChatGPT and it has nothing useful to say about you, you have an LLM SEO problem.
LLM SEO is the practice of optimising your digital presence so that large language models, the AI systems powering ChatGPT, Perplexity, Gemini, Claude, and Google AI Overviews, can find your content, understand your brand, and cite you as a source when answering relevant queries. It sits at the intersection of traditional SEO, entity optimisation, and a new set of technical requirements that didn't exist two years ago.
The term is new. The underlying mechanics aren't entirely new. But the way LLMs retrieve, evaluate, and present information is different enough from traditional search engines that relying on your existing SEO alone will leave gaps. This guide breaks down exactly how LLMs work as search systems, what they look for, and how to optimise specifically for them.
How LLMs retrieve information (training data vs real-time retrieval), how they evaluate which sources to cite, the role of entity recognition, content structure for LLM citation, technical requirements (Bing, schema, crawlers), the difference between LLM SEO and traditional SEO, and a practical optimisation framework. Written for SEO professionals and marketers who want the technical depth, not just the overview.
What is LLM SEO?
LLM SEO (sometimes called LLMO or LLM optimisation) is the practice of optimising your content and digital presence to be discoverable, understandable, and citable by large language models. Where traditional SEO focuses on ranking in Google's link-based results, LLM SEO focuses on being cited in AI-generated answers.
The "large language model" part refers to the AI systems behind the platforms people are increasingly using for search: GPT-4 and successors powering ChatGPT, Gemini powering Google's AI products, Claude powering Anthropic's search capabilities, and the models behind Perplexity's answer engine. These models process and generate text by understanding language at a deep statistical level, and they're becoming the primary interface through which millions of people find information.
The critical difference: traditional search engines crawl the web, build an index, and return links to pages. LLMs either retrieve information from their training data (the massive corpus of text they were trained on), browse the web in real time using a search index (typically Bing), or do both. The output isn't a list of links. It's a synthesised answer that may or may not cite your content as a source. Your goal in LLM SEO is to make sure it does.
For a broader overview of how this fits into the wider search marketing landscape, see our AEO vs SEO comparison.
How do LLMs retrieve and rank content?
This is the technical foundation that everything else builds on. LLMs use two main mechanisms to find and cite information, and understanding the difference between them is essential for effective optimisation.
Training data retrieval. Every LLM is trained on a massive dataset of text: web pages, books, articles, documentation, forums, and more. This training data has a cutoff date, after which the model doesn't "know" anything new. When you ask ChatGPT a general knowledge question, it's drawing from this training data. If your brand, your content, or your expertise was well-represented in the training corpus, the LLM has a baseline familiarity with you.
Real-time web retrieval (RAG). RAG stands for Retrieval-Augmented Generation. When an LLM needs current information, it searches the web (typically using Bing's index), retrieves relevant pages, and uses that content to generate its answer. This is how ChatGPT's web browsing mode works. Perplexity does this for every query. Google AI Overviews use Google's own index. The LLM doesn't just retrieve a link; it reads the content, extracts relevant information, and synthesises it into a response.
| Training Data | Real-Time Retrieval (RAG) | |
|---|---|---|
| How it works | Model draws from pre-trained knowledge | Model searches the web live and reads pages |
| Freshness | Frozen at training cutoff date | Current as of the moment of search |
| Your influence | Limited: depends on training corpus | High: optimise content for retrieval |
| Key platforms | ChatGPT (default mode), Claude | ChatGPT (browsing), Perplexity, AI Overviews, Gemini |
| Optimisation lever | Brand authority, entity presence, Wikipedia | Content structure, Bing indexing, structured data, freshness |
The practical implication: you need to optimise for both. Training data optimisation is about building a strong enough digital footprint that LLMs have absorbed information about your brand during training. Real-time retrieval optimisation is about structuring your content so that when an LLM searches the web for current information, your pages are retrieved and cited.
Most of the actionable LLM SEO work falls on the real-time retrieval side, because that's where you have direct control over what the LLM finds and how it processes your content.
How do LLMs decide which sources to cite?
When an LLM retrieves content from the web, it doesn't cite everything it reads. It evaluates sources based on several factors and selects the ones it deems most relevant, authoritative, and useful for the specific query.
Multi-source consensus. LLMs weight information more heavily when multiple independent sources agree on the same claim. If five credible sources say your business is the leading AEO agency in Australia, the LLM is more likely to include that claim than if only your own website says it. This is why building a citation portfolio across directories, editorial mentions, and third-party reviews matters so much. A Yext study of 6.8 million AI citations found that 86% of AI citations come from brand-managed sources: 44% first-party websites and 42% business listings and directories.
Content clarity and structure. LLMs prefer content that gives direct, clear answers that are easy to extract. Research from Kevin Indig found that 44.2% of AI citations come from the first 30% of a page's content. If your answer is buried halfway down a sprawling article, the LLM will cite someone who put the answer upfront.
Entity recognition. LLMs understand the world through entities: people, organisations, places, products, concepts. When an LLM can confidently match your brand to a known entity (because you have structured data, Wikipedia presence, consistent directory listings, and editorial mentions), it has higher confidence in citing you. More on this in the next section.
Freshness. For real-time retrieval, content freshness is a significant signal. BrightEdge found that 40-60% of ChatGPT citations change monthly. ConvertMate found that 76.4% of ChatGPT citations come from content updated within the past 30 days. Perplexity, which crawls fresh for every query, weights freshness even more aggressively.
Referring domain authority. Research from Higglo, analysing 129,000 domains, found that sites with over 32,000 referring domains receive 3.5x more AI citations. You don't need that many, but the principle is clear: the more credible external sources reference your brand, the more LLMs trust you.
Why does entity recognition matter for LLM SEO?
Entity recognition is the process by which an LLM identifies and understands what a piece of content is about and who created it. It's one of the most important (and most underappreciated) aspects of LLM SEO.
Traditional SEO operates on keywords: you optimise a page for a keyword, and Google matches that keyword to search queries. LLMs operate on entities: they understand that "Omni Eclipse" is an organisation, that it's an AEO agency, that it's based in Australia, and that Ashur Homa is associated with it. This entity understanding is what allows an LLM to recommend your brand in response to a prompt like "best AEO agencies in Australia" without you having optimised for that exact keyword phrase.
Building strong entity recognition requires consistency across your digital footprint:
Structured data (schema markup). Organisation schema on your homepage, Person schema for key team members, Article schema on your blog content. This is the machine-readable signal that tells LLMs exactly what entities are associated with your content.
Consistent NAP across directories. Name, Address, Phone number should be identical across every directory listing, review platform, and business profile. Inconsistencies confuse entity resolution.
Wikipedia and Wikidata presence. If your brand or key team members have a Wikipedia entry, that's a strong entity signal. Wikipedia is heavily weighted in LLM training data. Even if you don't qualify for Wikipedia, a Wikidata entry can help.
Editorial mentions that use your brand name consistently. When industry publications, news articles, and guest contributions consistently refer to your brand with the same name and context, LLMs build a stronger entity graph for your brand.
Content that establishes topical authority. Publishing deeply on a specific topic cluster (not just one article, but multiple pieces covering different angles of the same subject) signals to LLMs that your brand is an authority in that space. This is why content strategy matters for LLM SEO, not just individual page optimisation.
A growing number of websites are adopting llms.txt, a file (similar to robots.txt) that provides LLMs with a structured summary of what your website offers, who you are, and what topics you cover. While adoption is still early and not all LLMs read it yet, it's a low-effort signal that can help LLMs understand your site's scope and authority. If you're already doing LLM SEO, adding an llms.txt file to your root domain is worth the five minutes it takes.
How is LLM SEO different from traditional SEO?
The overlap is significant (roughly 80%), but the 20% that's different is what separates businesses that show up in AI search from those that don't.
| Factor | Traditional SEO | LLM SEO |
|---|---|---|
| Optimise for | Google search index | Multiple LLMs (ChatGPT, Perplexity, Gemini, Claude, AI Overviews) |
| Keyword approach | Exact match and semantic keywords | Entity-based: topical authority, brand association, contextual relevance |
| Content structure | Keyword-rich, topic clusters, internal linking | Direct-answer first paragraphs, question-format H2s, factual density |
| Technical foundation | Google crawlability, Core Web Vitals | Bing indexing, PerplexityBot access, structured data, llms.txt |
| Authority signals | Backlinks, domain authority, page authority | Multi-source consensus, citation portfolio, entity presence |
| Measurement | Rankings, traffic, CTR via Google Search Console | Visibility score, citation rate, AI referral traffic |
| Update cadence | Quarterly refresh for most content | Monthly or fortnightly (40-60% citation churn) |
| Competition level | Extremely competitive (25+ years of SEO) | Low competition currently, growing fast |
The biggest mindset shift for SEO professionals moving into LLM SEO: you're not competing for positions. You're competing for citations. There's no #1 ranking in ChatGPT. There's "cited as a trusted source" or "not mentioned at all." This changes how you prioritise, how you measure success, and how you think about competitive advantage.
What is a practical LLM SEO framework?
Here's the framework we use at Omni Eclipse, broken into four pillars.
Pillar 1: Content for Citation
Every key page on your site should answer questions that people ask LLMs. Use question-format H2 headings. Put the direct answer in the first paragraph. Support with specific data, named sources, and verifiable claims. Include FAQ sections with schema markup. Keep individual sections focused and concise.
Research from Peec AI, analysing 232,000 citations, found that list-based and comparative content makes up roughly 25% of all AI citations. If your topic lends itself to comparisons, tables, or ranked lists, use that format.
Pillar 2: Entity Authority
Build your brand as a recognisable entity across the web. Implement Organisation schema. Get listed in 10-15 relevant industry directories with consistent NAP information. Pursue editorial mentions in industry publications. Build topic clusters that establish deep authority on your core subjects. If applicable, create or improve your Wikipedia/Wikidata presence.
Pillar 3: Technical Access
Make sure LLMs can find and read your content. Submit your sitemap to Bing Webmaster Tools (critical for ChatGPT and Perplexity). Check that PerplexityBot and other AI crawlers aren't blocked in robots.txt. Implement structured data across your site. Ensure pages load fast and render content without heavy JavaScript dependencies. Consider adding an llms.txt file.
Pillar 4: Freshness and Maintenance
Set up a content refresh schedule. Update your highest-priority pages monthly. Add new data, reference recent studies, update "last modified" dates. Monitor your visibility across ChatGPT, Perplexity, Google AI Overviews, and Gemini. Track citation stability and be ready to refresh content when citations change.
For platform-specific optimisation, see our guides on how to rank in ChatGPT, how to rank in Perplexity, and how to optimise for Google AI Overviews.
“44% of consumers now prefer AI search for buying decisions. Traditional search is second at 31%. The businesses visible in LLM-powered search are capturing demand that traditional SEO alone can't reach.
Is your content visible to LLMs?
Book a free AI Visibility Audit. We'll test your brand across ChatGPT, Perplexity, Google AI Overviews, and Gemini, and show you exactly where LLMs can and can't find you.
Book Your AI Visibility AuditFrequently Asked Questions
What does LLM SEO stand for?
LLM SEO stands for Large Language Model Search Engine Optimisation. It's the practice of optimising your content and digital presence to be cited in AI-generated answers from large language models like ChatGPT (GPT-4), Gemini, Claude, and the models behind Perplexity and Google AI Overviews. It's also sometimes called LLMO (Large Language Model Optimisation). The concept overlaps heavily with AEO (Answer Engine Optimisation), which is the broader discipline of optimising for all AI answer engines.
Is LLM SEO the same as AEO?
Mostly, yes. LLM SEO focuses specifically on the large language model layer: how LLMs retrieve, process, and cite content. AEO is the broader term that covers optimisation for all answer engines, including LLM-powered ones (ChatGPT, Perplexity, Claude) and hybrid systems (Google AI Overviews, which combine LLM generation with Google's traditional search index). In practice, most of the optimisation techniques are identical. For a full comparison of the discipline, see our guide on what AEO is.
Do I need to optimise separately for each LLM?
The foundations are the same across all LLMs: clear content structure, strong entity signals, structured data, and authority across multiple sources. The platform-specific differences are mostly technical. ChatGPT relies on Bing's index for web browsing. Perplexity uses its own crawler plus Bing. Google AI Overviews use Google's index. Optimise the fundamentals once, then add the platform-specific technical requirements as incremental steps.
How do I know if my content is in an LLM's training data?
There's no public tool that lets you check this directly. The practical test is to ask ChatGPT, Claude, or Gemini about your brand or topic without web browsing enabled. If the model can discuss your brand with some accuracy, your content was likely in its training data. If it can't, you're relying entirely on real-time retrieval, which makes the optimisation strategies in this guide even more critical.
How long does LLM SEO take to show results?
For real-time retrieval optimisation (content restructuring, Bing indexing, structured data), you can see results within 2-4 weeks as LLMs retrieve your updated content. For training data influence, it depends on when the LLM is next updated, which for major models happens every few months. The fastest wins come from real-time retrieval optimisation: making sure your content is structured, indexed in Bing, accessible to AI crawlers, and regularly updated.

Ashur Homa
Built and scaled a digital brand to $100M+ in sales with zero ad spend. Has helped businesses generate millions through AI go-to-market strategy. Leads growth at Omni Eclipse.
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