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LLM SEO: How to Make Your Site Visible to AI Language Models

By Dimitris Drakatos, Founder, Wellknown

LLM SEO is the practice of making your website findable, readable and citable by large language models: the systems behind ChatGPT, Gemini, Perplexity and Claude. It starts somewhere most guides skip: not with what you write, but with what the models can physically read from your site, because the best content on the web is worth nothing to a model that was served an empty page.

The term sits in a crowded family. LLM SEO, GEO (generative engine optimisation) and AEO (answer engine optimisation) describe the same shift from three angles: the model, the engine, the answer. The names will keep fighting; the work underneath them is one discipline, and this page covers it end to end.

What is LLM SEO?

LLM SEO is optimising a website so that large language models can access it, understand it, and use it when generating answers. In practice that means three layers of work: access (letting the right crawlers and agents in), readability (serving them real content rather than a JavaScript shell), and citability (structuring pages so an answer engine can lift, quote and attribute them). Traditional SEO optimises for a ranking algorithm that returns a list; LLM SEO optimises for a language model that writes an answer, and you are either material for that answer or you are not.

How LLMs actually encounter your content

This is the part that changes how you prioritise everything else. An LLM meets your website through three separate doors, on three separate timelines, and most brands only think about the first.

Training data. Crawlers such as GPTBot and CCBot collect public web content that may become part of a future model's knowledge. This door moves on model-release cycles: what gets collected now shapes what a model "knows" months later. Blocking these crawlers keeps you out of that memory; allowing them is a decision about how deeply you want models to know you.

The search index. Agents such as OAI-SearchBot maintain the indexes behind AI search features. This door decides whether you are findable when the assistant searches the live web, and it refreshes on crawler timescales, days to weeks.

The live fetch. Agents such as ChatGPT-User retrieve a specific page in the middle of a conversation, because a real person just asked something your page can answer. This door is instant, it fires at the exact moment of buyer intent, and it is the one most often broken, because these agents do not reliably run JavaScript and frequently get served a shell. OpenAI alone runs one crawler for each of these three jobs, and blocking or breaking one does not affect the others.

The practical consequence: an LLM SEO problem is rarely one problem. A site can be in the training data, missing from the index and unreadable at fetch time all at once, and each failure has a different fix.

How to improve LLM SEO

In priority order. The order matters because each layer depends on the one before it.

1. Let the crawlers in, and check something has not decided for you

Audit robots.txt for rules naming GPTBot, ClaudeBot, CCBot, PerplexityBot or Google-Extended, then check your CDN, because providers such as Cloudflare now block AI crawlers by default for new domains and behind one-click security settings. Access is binary and upstream of everything else on this list.

2. Serve real HTML, not a JavaScript shell

If your content only exists after scripts run, most AI agents are reading a frame around nothing. Server-render anything you want models to read and cite. This single fix is, in our audits, the highest-impact change a JavaScript-heavy site can make.

3. Structure for extraction

Models lift fragments. Lead sections with the direct answer, use question-shaped headings, and write key facts as standalone sentences with the entity named, so a lifted line is still true and clear on its own.

4. Increase evidence density

The peer-reviewed GEO research, the KDD 2024 study from Princeton, IIT Delhi, Georgia Tech and the Allen Institute, found the biggest citation gains came from quotations, statistics and citations to authoritative sources. Specific and sourced beats vague and confident, every time.

5. Add an llms.txt file

A curated map of your best pages, written for LLM readers. Minutes to create, increasingly read, and covered properly in our llms.txt guide.

6. Keep entity facts consistent

Models reconcile what they read about you across your site, your profiles and the wider web. Prices, credentials, locations and claims should match everywhere, because inconsistency reads as unreliability to a system deciding whether to cite you.

7. Earn mentions beyond your site

What the wider web says about you weighs heavily in what models repeat. Reviews, expert commentary and reputable coverage compound slowly, so this lever starts early even though it pays late.

LLM SEO tools, services and audits

The tool question splits along the two layers of AI visibility. Tracking tools measure the appearance layer: how often you show up in AI answers, against which competitors, cited from which pages. They are useful scoreboards and they cannot see the mechanism underneath. Audits measure that mechanism: what each agent is actually served, what survives rendering, and what to fix in what order.

That second category is what we do. The AI search audit covers the assistants end to end, and the GEO audit extends it across Google's AI surfaces; both cost £3,500, need only your URL, and return a scored verdict with a ranked fix list within about a week. And if you are evaluating an LLM SEO consultant or service, whoever it is, one filter does most of the work: ask to see evidence at request level, what the agents were served, rather than screenshots of answers. Anyone doing this work properly can show you.

Frequently asked questions

What is LLM in SEO?

LLM stands for large language model, the AI systems behind ChatGPT, Gemini, Claude and Perplexity. In SEO, the term marks the shift from optimising for ranking algorithms to optimising for models that read your content and write answers from it.

Which LLM is best for SEO?

As tools for doing SEO work, they trade places with every release, so pick by task and taste. As targets for visibility, do not choose: the access and readability work in this guide serves all of them at once, which is precisely why it beats chasing any single assistant.

Is SEO dead or evolving in 2026?

Evolving. Search still drives significant traffic, and the foundations of technical SEO are also the foundations of LLM SEO. What has genuinely changed is that ranking and being cited have come apart, so a strategy built only on positions now misses the fastest-growing answer surface.

What is the difference between LLM SEO and GEO SEO?

Mostly the label. LLM SEO names the practice after the models, GEO (generative engine optimisation) names it after the engines; the full comparison with classic SEO covers what actually differs. The work, access, readability, extractability and evidence, is the same discipline underneath both terms.