Bing, Copilot and IndexNow: the forgotten engine that feeds ChatGPT
TL;DR
- Bing's index is the retrieval layer for ChatGPT (with search) and Microsoft Copilot. Outside Bing, you're invisible to two of the biggest AI engines.
- Studies point to ~87% overlap between ChatGPT's citations and Bing's top results. Bing is no longer optional.
- IndexNow notifies engines within seconds when you publish or change a URL. It's supported by Bing, Yandex, Naver, Seznam and Yep - but not Google.
- Registering in Bing Webmaster Tools and enabling IndexNow is the cheapest, most ignored GEO lever.
Everyone optimizes for Google and forgets Bing. But in the AI era, Bing is no longer "the other engine": it's the gateway to ChatGPT and Copilot. If you're not well indexed in Bing, you can rank on Google and still be invisible to two of the world's biggest AI assistants. It's the cheapest GEO mistake to fix.
Why Bing is the forgotten engine that matters
Because it's the retrieval layer for much of generative AI. ChatGPT with search and Microsoft Copilot pull sources from Bing's index; the same index feeds DuckDuckGo and Ecosia. A page that isn't in Bing is invisible to those engines - no matter how well it ranks on Google. Studies point to about 87% overlap between what ChatGPT cites and Bing's top results.
| AI engine | Leans on Bing? |
|---|---|
| ChatGPT (with search) | Yes (+ its own OAI-SearchBot) |
| Microsoft Copilot | Yes, entirely |
| Perplexity | Yes (Bing + own crawls) |
| Gemini / AI Overviews | No - Google's index |
IndexNow: near-instant indexing
IndexNow is an open protocol that notifies engines within seconds when you publish, update or delete a URL - instead of waiting for the next crawl. It's supported by Bing, Yandex, Naver, Seznam and Yep; Google tested it but doesn't support it (2026). Because Bing feeds Copilot and ChatGPT, getting into Bing faster means getting into the layer AI pulls answers from faster - around 22% of clicked Bing URLs come from IndexNow submissions.
How to make this work
Fast and low-effort:
- Create a Bing Webmaster Tools account and submit your sitemap (you can import the setup straight from Google Search Console).
- Enable IndexNow (many CMSs and CDNs, like Cloudflare, have one-click integration).
- Confirm you don't block BingBot or OAI-SearchBot in robots.txt.
- Check Bing indexing of your key pages - don't assume 'being on Google is enough'.
- Measure: use the <a href="/en/articles/search-console-ai-report/">GSC AI report</a> for the Google side and a prompt baseline for the Bing side (ChatGPT, Copilot, Perplexity).
It's part of the A - All-engine reach - of my CITAR method, and of what I do in GEO.
An honest read
Bing isn't everything: ChatGPT is building its own index (OAI-SearchBot) and relying less on Bing alone, and Gemini and AI Overviews live on Google's side. The ~87% overlap comes from a specific study and varies. Still, the takeaway holds: ignoring Bing leaves out a huge slice of generative AI, at the cost of half an hour of setup.
Key data
| Engines Bing feeds | ChatGPT search, Copilot, DuckDuckGo, Ecosia |
|---|---|
| ChatGPT ↔ Bing top overlap | ~87% |
| Bing clicks via IndexNow | 22% |
| IndexNow supported by | Bing, Yandex, Naver, Seznam, Yep |
| Does Google support IndexNow? | No |
ChatGPT also uses its own OAI-SearchBot and is building its own index; Bing is an important base, not the only one.
Sources: RankMax - Bing SEO 2026 · Pressonify - IndexNow 2026 · AlgoBlueprints - What search engine does ChatGPT use
Common mistakes and how to do it right
Ignoring Bing is the cheapest GEO mistake to fix. What separates those AI cites:
| Avoid | Do |
|---|---|
| ✗ Optimizing only for Google | ✓ Registering and submitting the site in Bing Webmaster Tools |
| ✗ Waiting days for indexing | ✓ Setting up IndexNow for near-instant indexing |
| ✗ Assuming Google is enough for ChatGPT | ✓ Confirming Bing indexing (base of Copilot and ChatGPT search) |
| ✗ Blocking BingBot/OAI-SearchBot by accident | ✓ Allowing indexing and real-time citation bots |
Tools I use and recommend
- Google Search ConsoleOrganic performance, coverage and field Core Web Vitals.
- ChatGPTAI assistant for research, analysis and quick audits.
- PerplexityAnswer engine with sources, useful for research and GEO.
- GeminiGoogle's AI assistant, grounded in Search.
- Screaming Frog SEO SpiderDesktop crawler for deep technical and on-page audits.
Sources
- RankMax - Bing SEO in 2026 (Copilot & ChatGPT)
- Pressonify - Does Google Support IndexNow in 2026?
- AlgoBlueprints - What Search Engine Does ChatGPT Use?
Frequently asked questions
Why does Bing matter for ChatGPT?
Because ChatGPT with search and Copilot pull sources from Bing's index. If you're not indexed in Bing, you're left out of those answers, even if you rank on Google. Get cited in ChatGPT →
What is IndexNow and is it worth it?
It's a protocol that notifies engines (Bing, Yandex, Naver, Seznam, Yep) within seconds when you change a URL. Worth it, especially for new content you want AI to reference fast. Google doesn't support it. Technical SEO checklist →
Does Google use IndexNow?
No. It tested it but hasn't adopted it (2026). For Google, you still rely on the normal crawl and Search Console. GEO guide →