AI SEO (GEO): How to Get Cited by ChatGPT, Gemini and Perplexity
Ask ChatGPT for the best 3D printing shop in Singapore and it does not show ten blue links. It writes one answer and names the two or three businesses it trusts. That is the shift: buyers who used to google now ask ChatGPT, Gemini and Perplexity, and those engines quote and cite their sources. Getting your business into the answer is called generative engine optimisation, or GEO. This guide covers the four-step method we run on every site we build, what it honestly can and cannot do, and a six-question self-check to score your own site.
What changes when buyers ask ChatGPT instead of Google?
A classic Google result is a ranked list. You fight for position, win the click, and your website does the selling. An AI answer works differently. The engine fetches a handful of pages, composes one reply, and cites where each claim came from. Google now does the same thing at the top of its own results with AI Overviews. Perplexity shows numbered footnotes. ChatGPT links its sources. In every case there is one answer, and your business is either in it or it is not.
So two properties decide who gets named. Fetchability: can the engine's crawler actually read your site? And quotability: once it is reading, does your copy contain a clear, liftable answer with a name attached? Some people call this discipline answer engine optimisation. The label matters less than those two properties.
● Google search
- Shows a ranked list of pages
- You optimise pages to rank for keywords
- Traffic lands on your site and your site sells
- Measured in positions, clicks and impressions
The four-step method we run on every site we build
Advice on this topic gets mystical fast. What we actually do is four concrete steps, and none of them takes more than a day.
1. Open the door in robots.txt
AI engines send named crawlers: GPTBot and OAI-SearchBot (OpenAI), ClaudeBot (Anthropic), PerplexityBot, Google-Extended and friends. Your robots.txt decides whether they get in, and plenty of site templates and "block bad bots" plugins shut them out wholesale, which makes everything else on this page pointless. We explicitly allow each of them on every public page and keep them out of admin areas only.
2. Ship llms.txt and llms-full.txt
These are plain-text files at your domain root that hand AI engines a structured summary: what you do, who you serve, what you charge, and links to the pages that prove it. Think of them as a menu written for machines. The rule that matters most is keep them current. Stale pricing in these files means every AI engine misquotes your business to every buyer who asks. We stamp ours with a last-updated date and refresh them in the same session as any pricing change. There is a full walkthrough in our llms.txt guide.
3. Write pages an engine can quote
Put the answer in the first 100 words of each key page: what you do, for whom, where, from what price. Attribute statements so they survive being lifted ("Aphyx builds and operates websites for Singapore SMEs" quotes cleanly; "we are passionate about digital" quotes as nothing). Then add FAQ schema, because answer engines lift question-and-answer pairs almost word for word.
4. Measure it, then spot-check it
GA4 now groups referral clicks from ChatGPT, Perplexity, Gemini and Copilot into an "AI Assistant" channel. Watching that channel go from zero to a steady trickle is the first hard proof the layer is working. One caveat: it only counts click-throughs, and most buyers read the answer without visiting, so treat it as the visible tip rather than the full footprint. The second check is manual. Once a month, ask each engine the questions your buyers ask, and note who gets named.
Does GEO replace normal SEO?
No, and be suspicious of anyone selling it that way. Answer engines lean heavily on the same signals Google uses: crawlable pages, real content, links, reviews, rankings. GEO is a layer on top of SEO, not a replacement for it. If your site is slow, thin, or invisible on Google, fix that first; our guide to choosing an SEO agency in Singapore covers what solid foundations look like.
Does it actually work?
Additive Inn, an Aphyx client that sells 3D printing services, is the cleanest example we can publish. Its site runs this exact stack: crawlers allowed, context files kept current, quotable copy, FAQ schema. When we spot-check ChatGPT with the questions its buyers ask, Additive Inn comes back at #2 in the recommendations for its niche. On our own site the evidence is smaller but consistent: engine descriptions of what we do and what we charge track the wording in our context files. Both are our observations from spot-checks, not a guarantee; we have also written up how businesses get found on ChatGPT in more detail.
AI engines do not rank you. They quote you. Give them something accurate to quote.
Before you change anything, score your own site. Six honest yes/no answers and you get your AI-visibility score, plus the one fix to do first.
AI Visibility Self-Check
Open your site in another tab and answer honestly. "Not sure" counts as no; the engines will not give you the benefit of the doubt either.
Want the answers checked for you? Our free audit simulates a live crawl from ChatGPT, Claude, Perplexity and Gemini against your site and scores what they actually see.
Run the free AI audit →Self-reported score. The free audit measures the same six areas from the engines' side.
Frequently asked questions
What is GEO in one line?
GEO (generative engine optimisation) is making your website easy for AI engines like ChatGPT, Gemini and Perplexity to fetch, quote and cite, so your business shows up inside their answers. Some people say answer engine optimisation instead; it is the same practice.
Does llms.txt actually work?
Honestly: no engine has promised to use it, so treat it as cheap insurance rather than a guarantee. The files take an hour to write, AI crawlers do fetch them, and on our own sites we have watched engine descriptions of our services and pricing track the wording in those files. Low cost, real upside.
How do I measure AI-search traffic?
Use the AI Assistant channel in GA4, which groups referral clicks from ChatGPT, Perplexity, Gemini and Copilot. Remember it only counts click-throughs; most people read the answer without visiting, so the real footprint is bigger than the number. Pair it with monthly spot-checks where you ask the engines your buyers' questions.
Should I stop doing normal SEO?
No. AI engines draw on the same underlying signals Google does, so weak SEO foundations mean weak AI visibility too. Do both: keep earning rankings, links and reviews, and add the GEO layer (crawler access, context files, quotable copy) on top. Sites that rank well are also the ones engines cite most.
Can I block AI crawlers instead?
Yes. Disallow GPTBot, ClaudeBot, PerplexityBot and friends in robots.txt and reputable crawlers will stay out. That makes sense when your content is the product, for example paid research you do not want summarised for free. For a business that wants leads, blocking mostly means the engines cite a competitor instead.
Written by the Aphyx team · Published 31 July 2026 · Last updated 31 July 2026
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