For twenty years, SEO meant one thing: ranking on Google. In 2026, the playing field has split. ChatGPT has 800 million monthly active users, Perplexity is establishing itself as a search alternative, Google AI Overviews capture a growing share of clicks, and Claude is being adopted in professional workflows. Optimising solely for blue links in Google is becoming a half-strategy. Welcome to AEO — Answer Engine Optimization.
What is AEO?
Answer Engine Optimization is the discipline of optimising your content for AI assistants and answer engines that produce direct synthesised replies, rather than lists of links. Where SEO targets “the user clicks on my page”, AEO targets “the AI cites my page in its answer”.
The difference matters: a Perplexity user who gets a complete answer rarely clicks through to source links. A ChatGPT user who asks “which is the best PrestaShop SEO module” will read the AI’s recommendation and act on it. If your site isn’t in the AI’s training corpus or accessible sources, you don’t exist for that user.
Why it matters now
Three factors converge in 2026 to make AEO unavoidable:
- Adoption: ChatGPT crossed 800 million weekly active users in late 2025. A non-trivial share of search behaviour has migrated.
- Google AI Overviews: Google now displays AI-generated summaries above its classic results on a growing range of queries. Even within Google, the answer-engine logic spreads.
- SearchGPT and Perplexity: pure answer engines emerge as alternatives to traditional search, especially for informational and commercial queries.
For an e-commerce site, the consequence is direct: if you want to be cited as “best module for X” or “trusted shop for Y”, you have to think AEO from now on.
How AEO differs from SEO
Classic SEO and AEO share fundamentals (quality content, technical site, semantic structure) but diverge on key points:
| Aspect | SEO | AEO |
|---|---|---|
| Goal | Rank #1 | Be cited in the answer |
| Engine | Google, Bing | ChatGPT, Perplexity, Claude, Google AIO |
| Format | Optimised page | Direct synthesisable answer |
| Structure | H1/H2, internal links | FAQPage, HowTo, llms.txt |
| Conversion | Click → site | Citation → notoriety, sometimes click |
The five engines to consider
1. ChatGPT (OpenAI)
The largest answer engine. Indexes the public web through the SearchGPT system. Optimisation: be referenced as a source on Wikipedia, Reddit, Stack Overflow, and quality industry sites. ChatGPT cites these sources by priority.
2. Perplexity
The pure answer engine. Always cites its sources with a click-out link, which makes it the most “SEO-friendly” of LLMs. Optimisation: clear and authoritative content, well-structured pages, FAQPage schema.
3. Claude (Anthropic)
Used in many professional workflows (research, writing, code). Less direct web search but high citation potential when accessed via API or plugins. Optimisation: clean technical documentation, well-named code on GitHub.
4. Google AI Overviews
The hybrid solution. Google synthesises the top results into a direct AI answer. Optimisation: classic SEO + Schema.org structured data on every page (FAQPage, HowTo, Product).
5. Gemini (Google)
The Google assistant integrated into Search and Workspace. Same logic as Google AI Overviews with more conversational handling.
Three concrete actions to start AEO today
Publish an llms.txt at your site root
The llms.txt file is the LLM equivalent of robots.txt: it tells AIs what to read by priority on your site. The file is placed at https://yoursite.com/llms.txt and follows a standardised Markdown format (specification at llmstxt.org).
Typical content: site presentation, list of priority pages with description, links to API or technical documentation. ChatGPT, Claude and Perplexity start to leverage these files for their indexing.
Strengthen FAQPage and HowTo schemas
The Schema.org structured data FAQPage and HowTo are direct citation gold. They give AIs explicit question/answer or step/action structures, which they reuse easily.
Concretely, on every product page, every category and every blog article: add 4 to 6 question/answer pairs in FAQPage format. Tools like Yoast SEO, Rank Math or our PrestaShop SEO modules add this automatically.
Write content that answers precise questions
An AEO-optimised article doesn’t read like an SEO article. It directly answers the question in the first paragraph (the AI extracts the introduction first), then expands. Title formats that work:
- “What is X?”
- “How to do X?”
- “Difference between X and Y”
- “Best X for Y”
- “Why X is essential”
Measuring AEO performance
This is the hard part: AEO is harder to measure than SEO. The classic tools (Search Console, Ahrefs, SEMrush) don’t yet expose citation rates in ChatGPT or Perplexity.
Available approaches in 2026:
- Manual queries — ask ChatGPT, Perplexity and Claude the strategic questions for your industry, see if your site is cited.
- Brand24 or Mention — these tools start tracking AI citations of your brand.
- Server logs — identify ChatGPT-User, PerplexityBot, ClaudeBot, GPTBot user agents to see what they crawl.
- Referrer traffic — Google Analytics 4 captures clicks from chat.openai.com, perplexity.ai, etc., as referrer sources.
Most common AEO mistakes
- Blocking AI bots in robots.txt — by reflex, many sites block GPTBot, ClaudeBot, PerplexityBot. The result: zero AEO chance. To be cited, you have to be readable.
- Walls of text without structure — AIs prefer clean H1/H2/H3, bulleted lists, comparison tables.
- Vague answers — AIs cite precise, sourced, dated answers. “Some studies say…” is far weaker than “according to the 2026 Baymard study, 70% of carts are abandoned.”
- Negative authority signals — AIs filter out low-quality sources. Spammy pages, fake reviews, splogs are excluded.
Going further
AEO is moving fast — what works in 2026 won’t necessarily work in 2027. Browse our AEO and Answer Engines category for monthly updates, and our E-commerce SEO category for the foundations on which AEO builds. For dedicated PrestaShop modules covering structured data, FAQPage and llms.txt, see our SEO & Search Optimisation category.