Optimizing for Each AI Search Engine
Tomohiro Iida ·
ChatGPT Search, Perplexity, Google AI Overviews, Microsoft Copilot, and Gemini all draw on different search infrastructure and different crawlers, so preparing for one does not automatically prepare you for the others. This guide summarizes the common groundwork that helps with every engine — being indexed, giving clear direct answers, making facts machine-readable, and having original first-party information — before walking through what is specific to each engine: which crawler it uses, what the 'Google-Extended' token actually controls, and why Bing is often an overlooked blind spot for companies that optimize only for Google. It closes with a comparison table and a checklist. Throughout, the guide is explicit that no technique can guarantee that any AI engine will cite or list a given company; the aim is to raise the odds of being found, not to promise placement.
Key takeaways
- The single biggest difference between the five engines is which search infrastructure they rely on: Copilot uses Bing, AI Overviews and Gemini use Google, and ChatGPT Search and Perplexity use their own crawlers — so the right preparation differs by engine.
- The common groundwork is the same across all of them: being indexed by search engines, having accurate content, and presenting it in a machine-readable structure. This is where to start regardless of which engine matters most to you.
- No engine can guarantee inclusion through any particular technique. This guide is about improving discoverability, not promising placement.
The common groundwork (what helps with every engine)
- Being indexed: if a search engine has not indexed a page, most AI engines cannot cite it as a source. This means fixing noindex tags, robots.txt misconfigurations, and content that only loads via client-side JavaScript.
- Clear, direct answers: state the conclusion first, keep one point per paragraph, and answer question-style headings directly. AI systems are more likely to quote a paragraph that makes sense on its own.
- Machine-readable facts: structure company information, services, and FAQs as text, and support them with structured data (schema markup).
- First-party information: generic statements can be found anywhere. Procedures, numbers, and judgment criteria that only your company can provide give an engine a reason to cite you.
- Clear entities: a consistent company name, address, and phone number (NAP), plus third-party mentions, help establish a business as a real, identifiable entity.
How each engine differs
- ChatGPT Search
- Uses OpenAI's own index. Its search crawler is OAI-SearchBot, distinct from GPTBot, which is used for model training. To appear in ChatGPT's search results, don't block OAI-SearchBot in robots.txt — blocking GPTBot alone (to opt out of training) does not affect search visibility.
- Perplexity
- Also uses its own index and crawlers: PerplexityBot for indexing and Perplexity-User for user-triggered page fetches. Perplexity foregrounds source links in its answers, so pages with clear, well-sourced claims and specific figures tend to be stronger citation candidates — though what actually gets cited is entirely Perplexity's own decision.
- Google AI Overviews
- A feature of Google Search with no dedicated crawler of its own; it relies on ordinary Googlebot indexing. Whether it appears varies by query, region, and time, and it does not show up for many queries at all. Standard SEO — indexing, E-E-A-T, search intent, structured data — applies directly.
- Microsoft Copilot
- Built on the Bing index, so being properly indexed by Bing is essential. Companies that optimize only for Google (common in Japan) often neglect Bing entirely, making this a frequent blind spot. Registering with Bing Webmaster Tools, submitting a sitemap, and supporting IndexNow are the key preparations.
- Gemini
- Google's generative AI. Its answers may draw on the model's trained knowledge plus, depending on the feature and settings, grounding from the Google Search index. Whether content can be used for training or grounding is controlled by the 'Google-Extended' robots.txt token — not a separate crawler — and blocking it has no effect on Google Search rankings or AI Overviews.
Engine comparison at a glance
| Engine | Search infrastructure | Crawler / control | Main preparation |
|---|---|---|---|
| ChatGPT Search | Own (OpenAI) | OAI-SearchBot (search) / GPTBot (training) | Allow the search crawler; cite sources clearly |
| Perplexity | Own | PerplexityBot / Perplexity-User | Allow the crawlers; provide well-sourced, primary information |
| Google AI Overviews | Googlebot (no dedicated bot) | Standard SEO; don't suppress your own snippets | |
| Microsoft Copilot | Bing | Bingbot | Get indexed by Bing; use IndexNow |
| Gemini | Googlebot / Google-Extended (a control token, not a crawler) | Standard SEO; decide a training-use policy |
What not to do, and the limits
- No engine can guarantee inclusion. Be skeptical of any method or service that claims it can get a business listed in AI answers for certain.
- Exaggeration and fabrication backfire. Don't state figures or achievements you cannot verify — a single inaccuracy can seriously damage trust.
- Don't over-invest in optimizing for one specific engine. Specifications change quickly; building a site that is accurate and well-structured for every engine is the more resilient investment.