ChatGPT Search

ChatGPT Search is the web search capability built into ChatGPT, which lets it fetch current information from the web and answer with links to the sources it used. OpenAI launched it on 31 October 2024 (after a SearchGPT prototype) and opened it to all users in supported regions, including logged-out users, on 5 February 2025. For SEOs it is one of the main AI search surfaces, alongside Perplexity, Google’s AI Overviews and AI Mode.

How it works

ChatGPT decides when a question needs fresh information, or the user turns search on. It rewrites the prompt into one or more search queries (the query fan-out pattern MLforSEO describes), retrieves pages, and writes an answer with inline citations and a Sources panel. OpenAI also has content partnerships with publishers, but a partnership is not required to appear.

Access is controlled by OpenAI’s crawlers. OpenAI’s documentation states that OAI-SearchBot is used to surface websites in ChatGPT’s search features and that sites opted out of it “will not be shown in ChatGPT search answers” (they may still appear as navigational links). GPTBot, the training crawler, is a separate decision, and ChatGPT-User handles user-initiated visits, where robots.txt rules may not apply.

How it’s used in SEO and marketing

• Crawler access. Check that robots.txt, firewalls and CDN rules allow OAI-SearchBot. Blocking GPTBot does not remove you from search answers; blocking OAI-SearchBot does.
• Prompt and citation tracking. Run a fixed set of customer questions monthly and record whether and how you are cited.
• Measuring referrals. ChatGPT appends utm_source=chatgpt.com to many outbound links, and GA4 now has a default AI Assistant channel, but visits without a referrer still show as direct.
• Content structure. In MLforSEO’s agent framework, ChatGPT Search is a research agent: it reads your text, so specific, extractable passages and clear entity signals still do real work.

Example

A marketer asks ChatGPT for the best tools to cluster keywords. ChatGPT runs several searches (“keyword clustering tools”, “BERTopic for SEO”, “KeyBERT keyword clustering”), reads the top results and answers with a short list, each tool linked to a source. A tutorial with a clear definition, a worked example and specific claims is more likely to be the linked source than a generic listicle.

Limitations and things to watch

• Answers vary between runs, users and models, and personalisation (memory, chat history) can change what is retrieved.
• OpenAI does not publish how sources are ranked or which search providers it uses for every query, so treat third-party claims about its index with care.
• Features change often. Shopping and checkout inside ChatGPT, for example, changed direction in March 2026 (see the Agentic Commerce Protocol). State facts with a date.

Learn it on MLforSEO

• Blog and Site Architecture for SEO and Conversions in the AI Search Era explains how ChatGPT search finds and cites pages.
• How Entities Power Query Fan-Out in AI Search covers the query expansion behind it.
• Your audience is no longer only human places ChatGPT Search among the three agent types.
• The AI Search Optimisation & Agentic SEO course teaches optimisation and measurement across AI search platforms.