The three dominant AI search platforms, Perplexity, ChatGPT Search, and Google Gemini, are not the same product. They use different retrieval architectures, different crawling infrastructure, and different signals to decide what to cite. Treating them as a single optimization target is a mistake that costs you visibility on the platforms most relevant to your audience.
This article breaks down how each platform works, what it favors, and the specific actions that improve your citation rate on each one: followed by the shared principles that apply across all three.
Key Takeaways
- Perplexity is the most retrieval-driven of the three platforms: it searches the web for each question, so a page it can crawl can be cited soon after it is published.
- ChatGPT Search finds pages through OAI-SearchBot and third-party search providers such as Bing, so allow OAI-SearchBot in robots.txt and make sure Bing has indexed your key pages. GPTBot is OpenAI's training crawler and does not control search visibility.
- Gemini and Google's AI Overviews and AI Mode are built on Google Search. Google says optimizing for them is still SEO: a page needs to be indexed and eligible to show a snippet, with no special schema or AI files required.
- Across all three platforms, the practices that help are the same: answer-first content structure, named expert authorship, cited primary data, and depth in a defined subject area.
- The most efficient approach is to optimize for the shared signals first, then apply platform-specific adjustments based on where your audience is most active.
How Perplexity Works and What It Favors
Perplexity is an AI-native search engine that performs real-time web searches in response to user queries, synthesizes the results, and presents an answer with source citations. Unlike ChatGPT or Gemini, which primarily draw on pre-trained model knowledge supplemented by retrieval, Perplexity's core behavior is retrieval-first: it is actively crawling the web to answer every query.
Perplexity uses its own crawler, PerplexityBot, which you can see in your server logs. According to Perplexity's crawler documentation, PerplexityBot is designed to surface and link websites in Perplexity's search results and is not used to train AI models. A second agent, Perplexity-User, visits pages when a user asks a question, and Perplexity says it generally ignores robots.txt because a person requested the fetch.
What Helps on Perplexity
- Freshness: Perplexity searches the web at the moment a question is asked, so for time-sensitive topics an up-to-date page with a visible last-updated date gives it a current answer to cite.
- Direct answer structure: Perplexity answers in short passages with links to its sources. A section that opens with a clear, direct answer gives it something easy to quote.
- Source diversity: Perplexity usually cites several sources per answer. Being one of three cited sources is still valuable, even if you are not the primary citation.
- Cited statistics: figures with a named, linked source are easier for any reader, human or AI, to trust and repeat than unsupported opinion.
How to Optimize Specifically for Perplexity
- Keep key pages current: update facts, figures and dates when things change, rather than publishing to a schedule for its own sake
- Use headings that say plainly which question each section answers, so readers and crawlers can find the answer quickly
- Ensure PerplexityBot is not blocked in robots.txt
- Keep pages fast and readable without heavy scripts, since Perplexity may fetch a page at the moment someone asks a question
How ChatGPT Search Works and What It Favors
ChatGPT Search is OpenAI's web search feature, built into the default ChatGPT interface. It launched for paid subscribers in October 2024, opened to all logged-in users that December, and since February 2025 has been available on chatgpt.com without an account. It combines the pre-trained knowledge in OpenAI's language models with real-time retrieval from OpenAI's own crawler and third-party search providers, which OpenAI says include Bing.
Two practical points follow. First, OAI-SearchBot must be allowed in your robots.txt: according to OpenAI's crawler documentation, it is the crawler used to surface websites in ChatGPT's search features, and sites that opt out of it won't appear in ChatGPT search answers. Second, Bing coverage is worth checking. Many SEO teams have focused entirely on Google indexing and neglected Bing, which leaves one fewer route for ChatGPT to find their pages.
What Helps on ChatGPT Search
- Crawler access: OAI-SearchBot must be allowed. Blocking GPTBot only opts your content out of model training; it does not remove you from ChatGPT search
- Bing coverage: a page Bing has not indexed is one less route into ChatGPT's answers, so check your key pages in Bing Webmaster Tools
- Visible expertise: named authors, cited data and first-hand detail give a page a reason to be quoted over a generic one
- Content structure: answer-first sections and clearly labeled headings improve extractability in the same way they do for other AI platforms
How to Optimize Specifically for ChatGPT Search
- Submit your sitemap to Bing Webmaster Tools and verify your site: a quick, worthwhile step if you have not done it
- Check Bing indexing coverage for your key pages using Bing Webmaster Tools' URL Inspection equivalent
- Ensure OAI-SearchBot is not blocked in your robots.txt: it is the crawler OpenAI uses to surface sites in ChatGPT search. GPTBot is separate and only governs whether your content may be used to train OpenAI's models
- Review your Bing Webmaster Tools data monthly alongside Google Search Console: treat Bing as a first-class channel, not an afterthought
How Google Gemini Works and What It Favors
Google Gemini is Google's AI assistant, powered by the Gemini language models. When it needs current information it can ground its answers in Google Search, and Google's AI features inside Search itself, AI Overviews and AI Mode, draw on the same index that powers traditional Google results.
This makes Gemini the most familiar territory for SEO teams. According to Google's guidance on AI features, optimizing for AI Overviews and AI Mode is still SEO: the same best practices apply, and there are no additional requirements or special optimizations.
What Helps on Gemini and Google's AI Features
- Indexing and snippet eligibility: Google says a page must be indexed and eligible to show in Search with a snippet to appear as a supporting link in AI Overviews or AI Mode
- Helpful, reliable content: the same people-first content Google's ranking systems are built to reward in traditional results
- No special markup: Google says there is no special schema.org structured data to add and no AI text files to create. Structured data still helps with rich results, but it is not an AI shortcut
- Freshness where it matters: Google's ranking systems include freshness systems for queries that call for current information
How to Optimize Specifically for Gemini
- Prioritize your standard Google SEO fundamentals: Google says the same best practices apply to its AI features
- Make sure key pages are indexed and can show a snippet: check them with Search Console's URL Inspection tool, and avoid nosnippet on pages you want cited
- Ensure your content has clear publication and last-updated dates that Google can read
- Cover your subject in depth with well-linked pillar and supporting pages, which helps readers and helps Google find and understand your content
- Track results in Search Console: Google includes traffic from AI Overviews and AI Mode in the Performance report, under the Web search type
The Shared Signals That Apply Across All Three Platforms
Despite their differences, a few practices help on Perplexity, ChatGPT Search, and Gemini alike. None of them is a secret ranking signal; they make a page easier to find, trust and quote:
- Answer-first content structure: direct answers in the first sentence or two of every section
- Named, credentialed authorship: identifiable authors with verifiable expertise in the topic area
- Cited primary data: statistics and claims attributed to named sources with years
- Topical depth: comprehensive coverage of a defined subject area, not superficial breadth
- Technical accessibility: fast load times, no crawler blocks, clean HTML structure
- FAQ sections: question-and-answer format content that maps directly to user queries
Optimize for these shared signals first. Platform-specific adjustments are meaningful margin improvements, but the shared signals are the foundation.
A Platform-by-Platform Checklist
Use this as a quick reference for prioritizing your optimization effort across platforms:
Perplexity: Allow PerplexityBot in robots.txt → publish content regularly → use question-format headings → cite statistics with sources → fast page load times.
ChatGPT Search: Allow OAI-SearchBot in robots.txt → submit sitemap to Bing Webmaster Tools → check Bing index coverage → build Bing authority through consistent quality publishing.
Gemini: Prioritize standard Google SEO → make sure key pages are indexed and snippet-eligible → build content clusters with strong internal linking → maintain and update existing content regularly.
All three: Answer-first structure → named authorship with credentials → cited data → topical depth → FAQ sections → technical health.
Frequently Asked Questions
Which AI search platform should I prioritize first?
Start with whichever platform your audience uses most. For B2B and professional audiences, ChatGPT Search and Perplexity are typically most relevant. For consumer queries, Google Gemini reaches the largest audience by far given Google's market share. If you are unsure, begin with the shared signals that apply across all three: that investment applies everywhere.
Can I block specific AI platforms from crawling my site?
Yes. Each platform has a named user agent you can block via robots.txt: PerplexityBot for Perplexity search, and OAI-SearchBot for ChatGPT search (GPTBot is OpenAI's separate training crawler). For Google, Google-Extended is a robots.txt control token rather than a separate crawler: it governs whether your content can be used to train Gemini models and to ground answers in the Gemini app, and Google says it does not affect inclusion or ranking in Google Search. To limit what Google's AI features in Search show from a page, Google points to its normal Search controls, such as nosnippet. Blocking a search crawler means that platform cannot surface your pages: it is a deliberate trade-off, not a default.
Does being cited on one AI platform help on others?
Not directly: the platforms use separate retrieval systems and do not share citation data with each other. However, the factors that make you citation-worthy on one platform (depth on your subject, clear structure, credentialed authorship) apply equally to others. Building these foundations benefits all platforms simultaneously.
Is Bing SEO really important now because of ChatGPT?
It matters more than it did. OpenAI says ChatGPT search draws on third-party search providers, Bing among them, so a page Bing has not indexed has one less route into ChatGPT's answers. Brands that have neglected Bing should verify their site in Bing Webmaster Tools and check index coverage for their key pages. Allowing OAI-SearchBot matters just as much.
How often do AI platforms update their citation sources?
Perplexity searches the web when a question is asked, so a newly published page can be found quickly once it is crawlable. ChatGPT Search depends on OAI-SearchBot and its search providers having seen the page, and Gemini and Google's AI features depend on Google having crawled and indexed it. None of the three publishes a timetable, so watch your own data: Search Console for Google (AI Overviews and AI Mode traffic is included in the Performance report), Bing Webmaster Tools for Bing, and referral traffic in your analytics for ChatGPT and Perplexity.
How do you check whether AI crawlers can access your pages?
Start with robots.txt: look for rules naming OAI-SearchBot, GPTBot, PerplexityBot or Claude-SearchBot, and for a blanket disallow that catches them. For Google's AI features, check Googlebot access the usual way, with the URL Inspection tool in Search Console. Next, check your CDN or firewall settings, which can block bots before robots.txt is ever read. Finally, look in your server logs for visits from those user agents and confirm they are genuine by matching the IP addresses against the ranges each company publishes, such as OpenAI's OAI-SearchBot list and Perplexity's PerplexityBot list, because anyone can fake a user agent.
The Bottom Line
Optimizing for AI search is not a single effort, it is three overlapping efforts with a shared foundation. The shared signals (answer-first structure, topical depth, named authorship, cited data) should come first. Platform-specific actions, particularly allowing OAI-SearchBot and checking Bing coverage for ChatGPT Search, and allowing PerplexityBot for Perplexity, close the remaining gap.
If you want a structured audit of your current AI search visibility across these platforms and a prioritized action plan, speak with our team. AI search optimization is a core part of how we approach AI SEO for our clients.
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Written by
Anjan LuthraManaging Partner, Indexed
Anjan Luthra is Managing Partner at Indexed. He has spent over a decade inside high-growth companies building organic search into their primary acquisition channel, and writes about SEO strategy, AI search, and revenue attribution.
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