ChatGPT Search vs Bing Copilot: how each picks its sources
ChatGPT Search and Bing Copilot both synthesize answers with citations, but their retrieval stacks differ. Here is how each chooses sources — and how to win both.
To a user, ChatGPT Search and Bing Copilot feel like the same product: ask a question, get a synthesized answer with a few citations. To an optimizer, they are two different retrieval systems wearing similar interfaces, and the differences change what you should prioritize.
Different retrieval stacks
Copilot is downstream of Bing. Its answers draw on Bing's index, so classic Bing SEO — verification, sitemaps, IndexNow, on-page quality — is the lever. ChatGPT Search uses OpenAI's own crawler (OAI-SearchBot) along with partner data, so being crawlable by that agent and being broadly cited across the open web matter more than your Bing standing.
What both reward
- Clean, server-rendered HTML with the answer near the top.
- Complete structured data — Article, FAQ, Organization, Product where relevant.
- Dated, recently updated content — freshness is a trust proxy.
- A crisp entity definition on your home page so the model knows what you are.
- Corroboration — being described consistently across many third-party sources.
Where they diverge
For Copilot, invest in Bing: verify the site, submit the sitemap, enable IndexNow, and cultivate links from Microsoft-adjacent properties like LinkedIn and GitHub. For ChatGPT Search, make sure OAI-SearchBot is allowed in robots.txt, and focus on broad, high-authority citations because the model's judgment of you is shaped by the whole web, not one index.
Measure them separately
Do not average them. Run the same prompt set against each engine and track citation rate, mention rate and share of voice per engine over time. It is common to be strong in one and weak in the other — and the fix is engine-specific.
Frequently asked questions
- Is Copilot just ChatGPT with Bing?
- They share model lineage, but the retrieval and product layers differ. Copilot is tied to Bing's index; ChatGPT Search uses OpenAI's own retrieval. Optimize for both.
- Which should I prioritize?
- For enterprise and Microsoft-heavy audiences, Copilot is often the faster win due to lower competition. For broad consumer research, ChatGPT Search has more reach.
- Does blocking one bot affect the other?
- Yes. Blocking OAI-SearchBot removes you from ChatGPT Search; blocking Bingbot removes you from Copilot. Audit robots.txt for both.