How Does ChatGPT Decide Which Sources to Cite?
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Quint-IA Vantage Team
ChatGPT searches the web when a question would benefit from current information. It rewrites the question into one or more targeted searches, sends them to search partners including Microsoft, and cites the pages it uses [1].
What it cites is spread across a very long tail of websites. Surfer tracked about 5.7 million ChatGPT citations in September 2026 and found that the 50 most-cited domains accounted for just 8.4% of them [3]. The other 91.6% went to sites outside that top 50.
That makes ChatGPT the answer engine where no single site dominates, and where a smaller company still has room. This piece explains when ChatGPT searches, which OpenAI crawlers reach your pages, how citations work, and what independent data shows. It draws on OpenAI's own documentation and studies from Ahrefs, Surfer, and Otterly.AI.
When does ChatGPT search the web?
ChatGPT searches automatically when it judges that a question would benefit from current information. OpenAI's help center says users can also start a search manually from the tools menu or by typing "/" in the message box [1].
Web search is available on every ChatGPT plan, including Free, and to people using ChatGPT without an account [1].
When ChatGPT searches, it does not send your exact words. OpenAI says it typically rewrites the question into one or more targeted queries and sends them to its search partners [1]. The help center names Microsoft among those partners, and Shopify for shopping results.
Query rewriting explains a pattern in Ahrefs' data. In a study of 15,000 queries from July 2025, Ahrefs found that 80% of the pages cited by ChatGPT, Gemini, and Copilot did not rank anywhere in Google for the original prompt [2]. Ahrefs attributes this to query fan-out: the engines search several variations of a prompt and merge the results.
Which OpenAI crawlers visit your site?
OpenAI runs separate crawlers (automated bots that read web pages) for search, for training, and for user requests. Each is controlled through robots.txt, the file that tells crawlers which pages they may visit, but they follow it differently [4].
OAI-SearchBot finds and surfaces websites in ChatGPT's search features. It follows robots.txt, and blocking it means your pages are not shown in ChatGPT search answers.
GPTBot collects content that may be used to train OpenAI's models. It follows robots.txt, and blocking it excludes your content from training.
ChatGPT-User visits pages for actions a user starts in ChatGPT. OpenAI says robots.txt rules may not apply to it, and it is not used to decide search appearance.
OAI-SearchBot is the one that controls your ChatGPT search visibility. OpenAI states that sites opted out of it will not be shown in ChatGPT search answers, though they can still appear as navigational links, and that changes to robots.txt take about 24 hours to apply [4].
OpenAI's help center adds a second requirement: your hosting provider or CDN must allow traffic from OpenAI's published search bot IP addresses [1]. Some firewalls block unfamiliar bots by default, so check this even if robots.txt is open.
Like Anthropic, OpenAI separates search from training. You can block GPTBot to keep your content out of training and still allow OAI-SearchBot so ChatGPT can cite you.
How does ChatGPT cite its sources?
ChatGPT shows citations inside the answer and lists them again under a Sources button. OpenAI's help center says users can select a citation to view the source, and open the Sources panel to see the cited pages and other relevant links [1].
That gives ChatGPT two places to show your page: as an inline citation next to a specific claim, or in the wider list of sources. Ahrefs measured them separately: 8.0% of in-text citations and 6.1% of reference-list citations also ranked in Google's top 10 for the same query [2].
OpenAI also warns that search results and citations can be incomplete, outdated, or incorrect [1]. When you check your visibility, look at what ChatGPT says your page claims, as well as whether it cites you.
Which sources does ChatGPT cite?
ChatGPT spreads its citations across a very long tail of websites. Surfer analyzed about 5.73 million citations from 1.23 million ChatGPT answers to 47,213 prompts in September 2026. The 50 most-cited domains accounted for just 8.4% of all citations [3].
Even the top domains hold small shares. Reddit was the most-cited domain at 0.74% of all citations, followed by Clutch, G2, Semrush, and Ahrefs [3].
reddit.com: 0.74%
clutch.co: 0.45%
g2.com: 0.37%
semrush.com: 0.37%
ahrefs.com: 0.30%
Two of the top three are review and directory sites. Within the top 50 domains, review and directory sites made up 23.6% of citations [3]. For B2B buyers asking ChatGPT to compare vendors, a complete profile on sites like Clutch and G2 gives ChatGPT another place to find you.
ChatGPT's citations also overlap little with search rankings. In Ahrefs' July 2025 study, about 8% of ChatGPT's citations ranked in Google's top 10 and about 8% in Bing's top 10 for the same query [2]. Perplexity's overlap with Google was 28.6% in the same study.
ChatGPT and Claude also cite different sites. Otterly.AI found that only 13% of the domains Claude cited were also cited by ChatGPT [5].
One limit to keep in mind: Surfer notes its dataset leans toward marketing, SaaS, and some Polish domains because of who uses its tool. The top-domain list would likely look different for other industries.
What should you do to get cited by ChatGPT?
Open the door for OAI-SearchBot, then cover each buyer question from several angles, on your site and on the review sites ChatGPT reads. Five steps follow from how ChatGPT searches and cites.
1. Allow OAI-SearchBot in robots.txt and in your firewall. OpenAI states that sites opted out of OAI-SearchBot are not shown in ChatGPT search answers, and that your host or CDN must allow its published IP addresses [4]. You can block GPTBot separately if you want to stay out of training.
2. Cover the variations of each buyer question. ChatGPT rewrites questions before searching, and in Ahrefs' study 80% of the pages cited by ChatGPT, Gemini, and Copilot did not rank in Google for the original prompt [2]. Build clusters of pages that answer the related questions and comparisons, so one of them matches the query ChatGPT writes.
3. Keep your profiles on review and directory sites complete. Clutch and G2 were the second and third most-cited domains in Surfer's September 2026 data [3]. Keep your services, pricing ranges, and client reviews current there.
4. Stay visible in Microsoft's search results. OpenAI names Microsoft among its search partners [1]. Verify your site in Bing Webmaster Tools and fix any indexing gaps it reports.
5. Track ChatGPT separately from Claude and Gemini. With citations spread across thousands of domains and little overlap between engines [5], you need to see which of your pages ChatGPT cites for your buyers' questions specifically.
What this means for your AI search plan
In ChatGPT, no single website dominates. It rewrites questions, searches through partners including Microsoft, and spreads citations so widely that the top 50 domains hold under a tenth of them. That leaves room for focused companies, provided OAI-SearchBot can reach their pages and their profiles on review sites are complete.
Frequently asked questions
Does ChatGPT search the web? Yes. ChatGPT searches automatically when a question would benefit from current information, and users can also start a search manually. Web search is available on all ChatGPT plans, including Free, and to users without an account. Answers that use search include inline citations and a Sources panel listing the pages used.
Does ChatGPT use Bing? OpenAI's help center says ChatGPT works with search partners and names Microsoft among them, along with Shopify for shopping results. ChatGPT rewrites a question into one or more targeted queries before sending them. In Ahrefs' July 2025 data, about 8% of ChatGPT's citations ranked in Bing's top 10 for the same query.
What is the difference between OAI-SearchBot, GPTBot, and ChatGPT-User? OAI-SearchBot surfaces websites in ChatGPT search, and sites that block it are not shown in search answers. GPTBot collects content that may be used for model training. ChatGPT-User visits pages for actions a user starts, and OpenAI says robots.txt rules may not apply to it.
Can I block ChatGPT from training on my site but still appear in its answers? Yes. Block GPTBot in robots.txt to opt out of training, and allow OAI-SearchBot so your pages can appear in ChatGPT search answers. OpenAI says robots.txt changes take about 24 hours to apply. Your host or CDN must also allow OpenAI's published search bot IP addresses.
Which websites does ChatGPT cite most? In Surfer's September 2026 data from about 5.7 million citations, Reddit was most cited at 0.74% of all citations, followed by Clutch, G2, Semrush, and Ahrefs. The 50 most-cited domains held only 8.4% of citations, so the large majority went to a long tail of other sites.
Do I need to rank in Google to be cited by ChatGPT? Ranking helps less than you might expect. In Ahrefs' July 2025 study, about 8% of ChatGPT's citations ranked in Google's top 10 for the same query, compared with 28.6% for Perplexity. ChatGPT rewrites questions into its own searches, so covering the variations of a question matters more than ranking for one phrase.
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References
OpenAI. "ChatGPT search." OpenAI Help Center. help.openai.com/en/articles/9237897
Linehan, L. and Guan, X. "AI Search Overlap." Ahrefs, published August 11, 2025 (data collected July 2025). ahrefs.com/blog/ai-search-overlap
Kaleta, P. "The 50 Most-Cited Domains in ChatGPT (September 2026)." Surfer, published October 5, 2026. surferseo.com/blog/most-cited-domains-chatgpt
OpenAI. "Overview of OpenAI Crawlers." OpenAI developer documentation. developers.openai.com/api/docs/bots
Tousseyn, R. "Claude AI Citations Study." Otterly.AI, published June 30, 2026. otterly.ai/blog/claude-ai-citation-study